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Author name code: magain
ADS astronomy entries on 2022-09-14
author:"Magain, Pierre"
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Title: COSMOGRAIL. XIX. Time delays in 18 strongly lensed quasars
from 15 years of optical monitoring
Authors: Millon, M.; Courbin, F.; Bonvin, V.; Paic, E.; Meylan, G.;
Tewes, M.; Sluse, D.; Magain, P.; Chan, J. H. H.; Galan, A.; Joseph,
R.; Lemon, C.; Tihhonova, O.; Anderson, R. I.; Marmier, M.; Chazelas,
B.; Lendl, M.; Triaud, A. H. M. J.; Wyttenbach, A.
2020A&A...640A.105M Altcode: 2020arXiv200205736M
We present the results of 15 years of monitoring lensed quasars, which
was conducted by the COSMOGRAIL programme at the Leonhard Euler 1.2
m Swiss Telescope. The decade-long light curves of 23 lensed systems
are presented for the first time. We complement our data set with
other monitoring data available in the literature to measure the time
delays in 18 systems, among which nine reach a relative precision
better than 15% for at least one time delay. To achieve this, we
developed an automated version of the curve-shifting toolbox PyCS
to ensure robust estimation of the time delay in the presence of
microlensing, while accounting for the errors due to the imperfect
representation of microlensing. We also re-analysed the previously
published time delays of RX J1131-1231 and HE 0435-1223, by adding
six and two new seasons of monitoring, respectively, and confirming
the previous time-delay measurements. When the time delay measurement
is possible, we corrected the light curves of the lensed images from
their time delay and present the difference curves to highlight the
microlensing signal contained in the data. To date, this is the largest
sample of decade-long lens monitoring data, which is useful to measure
H<SUB>0</SUB> and the size of quasar accretion discs with microlensing
as well as to study quasar variability. <P />All light curves presented
in this paper are only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr/">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/640/A105">http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/640/A105</A>
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Title: VizieR Online Data Catalog: R-band light curves of 23 lensed
QSOs (Millon+, 2020)
Authors: Millon, M.; Courbin, F.; Bonvin, V.; Paic, E.; Meylan, G.;
Tewes, M.; Sluse, D.; Magain, P.; Chan, J. H. H.; Galan, A.; Joseph,
R.; Lemon, C.; Tihhonova, O.; Anderson, R. I.; Marmier, M.; Chazelas,
B.; Lendl, M.; Triaud, A. H. M. J.; Wyttenbach, A.
2020yCat..36400105M Altcode:
R-band cosmograil light curves of lensed quasars taken at the Euler 1.2m
Swiss telescope with the EulerCAM and EulerC2 instrument. Additional
data taken at the SMARTS 1.3m telescope with the ANDICAM optical/
infrared camera are also included for SDSS J0924+0219 (MacLeod et
al., 2015ApJ...806..258M, Cat. J/ApJ/806/258). <P />For HE 0435-1223
and RX J1131-1231, data taken at the 1.5m telescope at the Maidanak
Observatory, the Mercator Belgian telescope and at the SMARTS 1.3
m telescope are included (Courbin et al. 2011A&A...536A..53C,
Cat, J/A+A/536/A53, Tewes et al. 2013A&A...553A.120T,
2013A&A...556A..22T, Cat. J/A+A/556/A22). For SDSS J1515+1511,
we had the data from Shalyapin & Goicoechea (2017ApJ...836...14S)
from the Liverpool Telescope. <P />(5 data files).
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Title: COSMOGRAIL. XVII. Time delays for the quadruply imaged quasar
PG 1115+080
Authors: Bonvin, V.; Chan, J. H. H.; Millon, M.; Rojas, K.; Courbin,
F.; Chen, G. C. -F.; Fassnacht, C. D.; Paic, E.; Tewes, M.; Chao,
D. C. -Y.; Chijani, M.; Gilman, D.; Gilmore, K.; Williams, P.;
Buckley-Geer, E.; Frieman, J.; Marshall, P. J.; Suyu, S. H.; Treu,
T.; Hempel, A.; Kim, S.; Lachaume, R.; Rabus, M.; Anguita, T.; Meylan,
G.; Motta, V.; Magain, P.
2018A&A...616A.183B Altcode: 2018arXiv180409183B
We present time-delay estimates for the quadruply imaged quasar PG
1115+080. Our results are based on almost daily observations for
seven months at the ESO MPIA 2.2 m telescope at La Silla Observatory,
reaching a signal-to-noise ratio of about 1000 per quasar image. In
addition, we re-analyze existing light curves from the literature
that we complete with an additional three seasons of monitoring with
the Mercator telescope at La Palma Observatory. When exploring the
possible source of bias we considered the so-called microlensing
time delay, a potential source of systematic error so far never
directly accounted for in previous time-delay publications. In
15 yr of data on PG 1115+080, we find no strong evidence of
microlensing time delay. Therefore not accounting for this effect,
our time-delay estimates on the individual data sets are in good
agreement with each other and with the literature. Combining the
data sets, we obtain the most precise time-delay estimates to date
on PG 1115+080, with Δt(AB) = 8.3<SUP>+1.5</SUP><SUB>-1.6</SUB>
days (18.7% precision), Δt(AC) = 9.9<SUP>+1.1</SUP><SUB>-1.1</SUB>
days (11.1%) and Δt(BC) = 18.8<SUP>+1.6</SUP><SUB>-1.6</SUB> days
(8.5%). Turning these time delays into cosmological constraints
is done in a companion paper that makes use of ground-based
Adaptive Optics (AO) with the Keck telescope. <P />Lightcurve
data points are only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr/">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/616/A183">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/616/A183</A>
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Title: A cosmology-independent calibration of Type Ia supernovae data
Authors: Hauret, C.; Magain, P.; Biernaux, J.
2018MNRAS.479.3996H Altcode: 2018arXiv180610900H; 2018MNRAS.tmp.1635H
Recently, the common methodology used to transform Type Ia
supernovae (SNe Ia) into genuine standard candles has been suffering
criticism. Indeed, it assumes a particular cosmological model [namely
the flat Λ cold dark matter (ΛCDM)] to calibrate the standardization
corrections parameters, i.e. the dependence of the supernova peak
absolute magnitude on its colour, post-maximum decline rate and host
galaxy mass. As a result, this assumption could make the data compliant
to the assumed cosmology and thus nullify all works previously conducted
on model comparison. In this work, we verify the viability of these
hypotheses by developing a cosmology-independent approach to standardize
SNe Ia data from the recent JLA compilation. Our resulting corrections
turn out to be very close to the ΛCDM-based corrections. Therefore,
even if a ΛCDM-based calibration is questionable from a theoretical
point of view, the potential compliance of SNe Ia data does not happen
in practice for the JLA compilation. Previous works of model comparison
based on these data do not have to be called into question. However,
as this cosmology-independent standardization method has the same
degree of complexity than the model-dependent one, it is worth using
it in future works, especially if smaller samples are considered,
such as the superluminous Type Ic supernovae.
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Title: VizieR Online Data Catalog: R-band light curves of PG 1115+080
(Bonvin+, 2018)
Authors: Bonvin, V.; Chan, J. H. H.; Millon, M.; Rojas, K.; Courbin,
F.; Chen, G. C. -F.; Fassnacht, C. D.; Paic, E.; Tewes, M.; Chao,
D. C. -Y.; Chijani, M.; Gilman, D.; Gilmore, K.; Williams, P.;
Buckley-Geer, E.; Frieman, J.; Marshall, P. J.; Suyu, S. H.; Treu,
T.; Hempel, A.; Kim, S.; Lachaume, R.; Rabus, M.; Anguita, T.; Meylan,
G.; Motta, V.; Magain, P.
2018yCat..36160183B Altcode:
We have been monitoring the quadruply lensed quasar PG1115+080 for 8
months in the R band (~600-720nm) using the MPIA/ESO 2.2m telescope. The
resulting R-band light curves of the quadruply lensed quasar PG1115+080,
is displayed in Fig. 2 of the paper. <P />(1 data file).
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Title: High-precision multiwavelength eclipse photometry of the
ultra-hot gas giant exoplanet WASP-103 b
Authors: Delrez, L.; Madhusudhan, N.; Lendl, M.; Gillon, M.; Anderson,
D. R.; Neveu-VanMalle, M.; Bouchy, F.; Burdanov, A.; Collier-Cameron,
A.; Demory, B. -O.; Hellier, C.; Jehin, E.; Magain, P.; Maxted,
P. F. L.; Queloz, D.; Smalley, B.; Triaud, A. H. M. J.
2018MNRAS.474.2334D Altcode: 2017arXiv171102566D
We present 16 occultation and three transit light curves for the
ultra-short period hot Jupiter WASP-103b, in addition to five new radial
velocity measurements. We combine these observations with archival
data and perform a global analysis of the resulting extensive data
set, accounting for the contamination from a nearby star. We detect
the thermal emission of the planet in both the z<SUP>΄</SUP> and
K<SUB>S</SUB> bands, the measured occultation depths being 699±110
ppm (6.4σ) and 3567_{-350}^{+400} ppm (10.2σ), respectively. We use
these two measurements, together with recently published HST/WFC3 data,
to derive joint constraints on the properties of WASP-103b's dayside
atmosphere. On one hand, we find that the z<SUP>΄</SUP> band and
WFC3 data are best fit by an isothermal atmosphere at 2900 K or an
atmosphere with a low H<SUB>2</SUB>O abundance. On the other hand,
we find an unexpected excess in the K<SUB>S</SUB> band measured flux
compared to these models, which requires confirmation with additional
observations before any interpretation can be given. From our global
data analysis, we also derive a broad-band optical transmission spectrum
that shows a minimum around 700 nm and increasing values towards both
shorter and longer wavelengths. This is in agreement with a previous
study based on a large fraction of the archival transit light curves
used in our analysis. The unusual profile of this transmission spectrum
is poorly matched by theoretical spectra and is not confirmed by more
recent observations at higher spectral resolution. Additional data,
in both emission and transmission, are required to better constrain
the atmospheric properties of WASP-103b.
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Title: Analysis of luminosity distributions of strong lensing
galaxies: subtraction of diffuse lensed signal
Authors: Biernaux, J.; Magain, P.; Hauret, C.
2017A&A...604A..46B Altcode: 2017arXiv170502282B
Context. Strong gravitational lensing gives access to the total mass
distribution of galaxies. It can unveil a great deal of information
about the lenses' dark matter content when combined with the study of
the lenses' light profile. However, gravitational lensing galaxies,
by definition, appear surrounded by lensed signal, both point-like and
diffuse, that is irrelevant to the lens flux. Therefore, the observer is
most often restricted to studying the innermost portions of the galaxy,
where classical fitting methods show some instabilities. <BR /> Aims: We
aim at subtracting that lensed signal and at characterising some lenses'
light profile by computing their shape parameters (half-light radius,
ellipticity, and position angle). Our objective is to evaluate the total
integrated flux in an aperture the size of the Einstein ring in order
to obtain a robust estimate of the quantity of ordinary (luminous)
matter in each system. <BR /> Methods: We are expanding the work we
started in a previous paper that consisted in subtracting point-like
lensed images and in independently measuring each shape parameter. We
improve it by designing a subtraction of the diffuse lensed signal,
based only on one simple hypothesis of symmetry. We apply it to the
cases where it proves to be necessary. This extra step improves our
study of the shape parameters and we refine it even more by upgrading
our half-light radius measurement method. We also calculate the impact
of our specific image processing on the error bars. <BR /> Results:
The diffuse lensed signal subtraction makes it possible to study a
larger portion of relevant galactic flux, as the radius of the fitting
region increases by on average 17%. We retrieve new half-light radii
values that are on average 11% smaller than in our previous work,
although the uncertainties overlap in most cases. This shows that not
taking the diffuse lensed signal into account may lead to a significant
overestimate of the half-light radius. We are also able to measure
the flux within the Einstein radius and to compute secure error bars
to all of our results.
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Title: Cosmological Time, Entropy and Infinity
Authors: Hauret, Clémentine; Magain, Pierre; Biernaux, Judith
2017Entrp..19..357H Altcode:
Time is a parameter playing a central role in our most fundamental
modelling of natural laws. Relativity theory shows that the comparison
of times measured by different clocks depends on their relative
motion and on the strength of the gravitational field in which they
are embedded. In standard cosmology, the time parameter is the one
measured by fundamental clocks (i.e., clocks at rest with respect
to the expanding space). This proper time is assumed to flow at a
constant rate throughout the whole history of the universe. We make
the alternative hypothesis that the rate at which the cosmological time
flows depends on the dynamical state of the universe. In thermodynamics,
the arrow of time is strongly related to the second law, which states
that the entropy of an isolated system will always increase with time
or, at best, stay constant. Hence, we assume that the time measured
by fundamental clocks is proportional to the entropy of the region
of the universe that is causally connected to them. Under that simple
assumption, we find it possible to build toy cosmological models that
present an acceleration of their expansion without any need for dark
energy while being spatially closed and finite, avoiding the need to
deal with infinite values.
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Title: A seven-planet resonant chain in TRAPPIST-1
Authors: Luger, Rodrigo; Sestovic, Marko; Kruse, Ethan; Grimm, Simon
L.; Demory, Brice-Olivier; Agol, Eric; Bolmont, Emeline; Fabrycky,
Daniel; Fernandes, Catarina S.; Van Grootel, Valérie; Burgasser,
Adam; Gillon, Michaël; Ingalls, James G.; Jehin, Emmanuël; Raymond,
Sean N.; Selsis, Franck; Triaud, Amaury H. M. J.; Barclay, Thomas;
Barentsen, Geert; Howell, Steve B.; Delrez, Laetitia; de Wit, Julien;
Foreman-Mackey, Daniel; Holdsworth, Daniel L.; Leconte, Jérémy;
Lederer, Susan; Turbet, Martin; Almleaky, Yaseen; Benkhaldoun, Zouhair;
Magain, Pierre; Morris, Brett M.; Heng, Kevin; Queloz, Didier
2017NatAs...1E.129L Altcode: 2017NatAs...1..129L; 2017arXiv170304166L
The TRAPPIST-1 system is the first transiting planet system found
orbiting an ultracool dwarf star<SUP> 1 </SUP>. At least seven planets
similar in radius to Earth were previously found to transit this host
star<SUP> 2 </SUP>. Subsequently, TRAPPIST-1 was observed as part of
the K2 mission and, with these new data, we report the measurement
of an 18.77 day orbital period for the outermost transiting planet,
TRAPPIST-1 h, which was previously unconstrained. This value matches
our theoretical expectations based on Laplace relations<SUP> 3 </SUP>
and places TRAPPIST-1 h as the seventh member of a complex chain, with
three-body resonances linking every member. We find that TRAPPIST-1 h
has a radius of 0.752 R <SUB>⊕</SUB> and an equilibrium temperature of
173 K. We have also measured the rotational period of the star to be
3.3 days and detected a number of flares consistent with a low-activity,
middle-aged, late M dwarf.
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Title: Seven temperate terrestrial planets around the nearby ultracool
dwarf star TRAPPIST-1
Authors: Gillon, Michaël; Triaud, Amaury H. M. J.; Demory,
Brice-Olivier; Jehin, Emmanuël; Agol, Eric; Deck, Katherine M.;
Lederer, Susan M.; de Wit, Julien; Burdanov, Artem; Ingalls, James
G.; Bolmont, Emeline; Leconte, Jeremy; Raymond, Sean N.; Selsis,
Franck; Turbet, Martin; Barkaoui, Khalid; Burgasser, Adam; Burleigh,
Matthew R.; Carey, Sean J.; Chaushev, Aleksander; Copperwheat, Chris
M.; Delrez, Laetitia; Fernandes, Catarina S.; Holdsworth, Daniel L.;
Kotze, Enrico J.; Van Grootel, Valérie; Almleaky, Yaseen; Benkhaldoun,
Zouhair; Magain, Pierre; Queloz, Didier
2017Natur.542..456G Altcode: 2017arXiv170301424G
One aim of modern astronomy is to detect temperate,
Earth-like exoplanets that are well suited for atmospheric
characterization. Recently, three Earth-sized planets were detected
that transit (that is, pass in front of) a star with a mass just eight
per cent that of the Sun, located 12 parsecs away. The transiting
configuration of these planets, combined with the Jupiter-like size of
their host star—named TRAPPIST-1—makes possible in-depth studies of
their atmospheric properties with present-day and future astronomical
facilities. Here we report the results of a photometric monitoring
campaign of that star from the ground and space. Our observations
reveal that at least seven planets with sizes and masses similar to
those of Earth revolve around TRAPPIST-1. The six inner planets form
a near-resonant chain, such that their orbital periods (1.51, 2.42,
4.04, 6.06, 9.1 and 12.35 days) are near-ratios of small integers. This
architecture suggests that the planets formed farther from the star
and migrated inwards. Moreover, the seven planets have equilibrium
temperatures low enough to make possible the presence of liquid water
on their surfaces.
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Title: Red worlds: Spitzer exploration of a compact system of
temperate terrestrial planets transiting a nearby Jupiter-sized star
Authors: Gillon, Michael; Burdanov, Artem; Delrez, Laetitia; Jehin,
Emmanuel; Magain, Pierre; Van Grootel, Valerie; Bolmont, Emeline;
Leconte, Jeremy; Raymond, Sean; Selsis, Franck; Demory, Brice-Olivier;
Queloz, Didier; Triaud, Amaury; de Wit, Julien; Burgasser, Adam;
Carey, Sean; Ingalls, Jim; Lederer, Sue; Agol, Eric; Deck, Katherine
2016sptz.prop13067G Altcode:
The recently detected TRAPPIST-1 planetary system represents a unique
opportunity to extend the nascent field of comparative exoplanetology
into the realm of temperate terrestrial worlds. It is composed of at
least three Earth-sized planets similar in sizes and irradiations to
Earth and Venus transiting an ultra-cool dwarf star only 39 light-years
away. Thanks to the Jupiter-size and infrared brightness of their host
star, the planets are amenable for detailed atmospheric characterization
with JWST, including for biosignatures detection. Our Spitzer
Exploration Science Program aims to prepare and optimize the detailed
study of this fascinating planetary system through the two following
complementary sub-programs: (1) a 480 hrs continuous monitoring of
the star to explore its full inner system up to its ice line in a
search for any other transiting object(s) (planet, moon, Trojan) with a
sensitivity high enough to detect any body as small as Ganymede, and (2)
the observation of ~130 transits of the planets (520 hrs). This second
part has two goals. First, to measure precisely the planets' masses
and eccentricities through the Transit Timing Variations method, to
constrain strongly their compositions and energy budgets. Secondly, to
measure with an extremely high precision the planets' effective radii at
4.5 microns to assess, when combined with future HST/WFC3 observations,
the presence of an atmosphere around them. The two complementary parts
of this program will make it a long-lasting legacy of Spitzer to the
fields of comparative exoplanetology and astrobiology, by providing
the necessary measurements on the inner system of TRAPPIST-1 (complete
census, masses, eccentricities, first insights on atmospheres) required
to initiate and optimize the detailed atmospheric characterization
of its different components with JWST and other future facilities. <P
/>Data from program 13175 can also be found in this program.
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Title: Variable time flow as an alternative to dark energy
Authors: Magain, Pierre; Hauret, Clémentine
2016arXiv160606169M Altcode:
Time is a parameter playing a central role in our most fundamental
modelling of natural laws. Relativity theory shows that the comparison
of times measured by different clocks depends on their relative
motions and on the strength of the gravitational field in which they
are embedded. In standard cosmology, the time parameter is the one
measured by fundamental clocks, i.e. clocks at rest with respect to the
expanding space. This proper time is assumed to flow at a constant rate
throughout the whole history of the Universe. We make the alternative
hypothesis that the rate at which cosmological time flows depends on the
global geometric curvature the Universe. Using a simple one-parameter
model for the relation between proper time and curvature, we build
a cosmological model that fits the Type Ia Supernovae data (the best
cosmological standard candles) without the need for dark energy nor
probably exotic dark matter.
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Title: Temperate Earth-sized planets transiting a nearby ultracool
dwarf star
Authors: Gillon, Michaël; Jehin, Emmanuël; Lederer, Susan M.; Delrez,
Laetitia; de Wit, Julien; Burdanov, Artem; Van Grootel, Valérie;
Burgasser, Adam J.; Triaud, Amaury H. M. J.; Opitom, Cyrielle; Demory,
Brice-Olivier; Sahu, Devendra K.; Bardalez Gagliuffi, Daniella;
Magain, Pierre; Queloz, Didier
2016Natur.533..221G Altcode: 2016arXiv160507211G
Star-like objects with effective temperatures of less than
2,700 kelvin are referred to as ‘ultracool dwarfs’. This
heterogeneous group includes stars of extremely low mass as well
as brown dwarfs (substellar objects not massive enough to sustain
hydrogen fusion), and represents about 15 per cent of the population
of astronomical objects near the Sun. Core-accretion theory predicts
that, given the small masses of these ultracool dwarfs, and the
small sizes of their protoplanetary disks, there should be a large
but hitherto undetected population of terrestrial planets orbiting
them—ranging from metal-rich Mercury-sized planets to more hospitable
volatile-rich Earth-sized planets. Here we report observations of
three short-period Earth-sized planets transiting an ultracool dwarf
star only 12 parsecs away. The inner two planets receive four times
and two times the irradiation of Earth, respectively, placing them
close to the inner edge of the habitable zone of the star. Our data
suggest that 11 orbits remain possible for the third planet, the most
likely resulting in irradiation significantly less than that received
by Earth. The infrared brightness of the host star, combined with its
Jupiter-like size, offers the possibility of thoroughly characterizing
the components of this nearby planetary system.
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Title: Long-term activity and outburst of comet C/2013 A1 (Siding
Spring) from narrow-band photometry and long-slit spectroscopy
Authors: Opitom, C.; Guilbert-Lepoutre, A.; Jehin, E.; Manfroid,
J.; Hutsemékers, D.; Gillon, M.; Magain, P.; Roberts-Borsani, G.;
Witasse, O.
2016A&A...589A...8O Altcode: 2015arXiv151007514O
We present a unique data set of more than one year's worth of regular
observations of comet C/2013 A1(Siding Spring) taken with TRAPPIST,
along with low-resolution spectra obtained with the ESO/VLT FORS 2
instrument. The comet made a close approach to Mars on October 19,
2014, and was then observed by many space-borne and ground-based
telescopes. We followed the evolution of the OH, NH, CN, C<SUB>3</SUB>,
and C<SUB>2</SUB> production rates as well as the Afρ parameter,
a proxy for the dust production. We detected an outburst two weeks
after perihelion, with gas and dust production rates increased by a
factor of five within a few days. By modelling the shape of the CN
and C<SUB>2</SUB> radial profiles, we determined that the outburst
happened on November 10 around 15:30 UT (±5 h) and measured a gas
expansion velocity of 1.1 ± 0.2 km s<SUP>-1</SUP>. We used a thermal
evolution model to reproduce the activity pattern and outburst. Our
results are consistent with the progressive formation of a dust
mantle explaining the shallow dependence of gas production rates,
which may be partially blown off during the outburst. We studied the
evolution of gas composition, using various ratios such as CN/OH,
C<SUB>2</SUB>/OH, or C<SUB>3</SUB>/OH, which showed little or no
variation with heliocentric distance, including at the time of the
outburst. This indicates a relative level of homogeneity of the nucleus
composition. <P />Based on observations obtained at the ESO/VLT in
the framework of program 93.C-0619.
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Title: Two Birds One Stone: Simultaneous Atmospheric Pre-Screening
of Two Temperate Earth-Sized Exoplanets During Their Double Transit
Authors: de Wit, Julien; Burdanov, Artem; Burgasser, Adam J.; Delrez,
Laetitia; Demory, Brice-Olivier; Gillon, Michael; Jehin, Emmanuel;
Lederer, Susan; Lewis, Nikole; Magain, Pierre; Queloz, Didier; Triaud,
Amaury; Van Grootel, Valerie
2016hst..prop14500D Altcode:
We have detected three temperate Earth-sized planets transiting an
ultra-cool dwarf star only 12 pc away, TRAPPIST-1. This discovery sparks
the era of detailed characterization and habitability assessment of
Earth-sized exoplanets. It also opens a new chapter for exoplanetology:
comparative planetology in the realm of temperate terrestrial
planets. <P />TRAPPIST-1's system is currently the subject of an
intense, worldwide follow-up effort that spans the electromagnetic
spectrum from the UV to radio. Being uniquely suited for NIR and
UV high-precision observations, HST has a key role to play in this
follow-up effort. <P />Updated ephemerids resulting from two Spitzer
DDTs show that TRAPPIST-1 b and c will transit simultaneously on May
4th, 2016 at 9h10 UT providing a unique and rare opportunity to study
for the first time, and simultaneously, the atmospheres of temperate
Earth-sized planets outside of the Solar System. We propose a 4-orbit
pre-screening program with WFC3 to definitely test the H/He-dominated
atmospheric scenario for these planets and determine the relative
inclination of both planets, bringing invaluable constraints on the
dynamical history of the system.
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Title: On the eclipsing binary nature of a nearby ultracool dwarf
Authors: Gillon, Michael; Jehin, Emmanuel; de Wit, Julien; Demory,
Brice-Olivier; Burgasser, Adam; Van Grootel, Valerie; Lederer, Susan;
Triaud, Amaury; Delrez, Laetitia; Burdanov, Artem; Queloz, Didier;
Magain, Pierre
2016sptz.prop12130G Altcode:
The eclipsing binary nature of a nearby ultracool dwarf has just been
revealed. The aim of this DDT is to investigate this nearby system
further through high-precision infrared time-series photometry.
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Title: On the eclipsing binary nature of a nearby ultracool dwarf
Authors: Gillon, Michael; de Wit, Julien; Jehin, Emmanuel; Burdanov,
Artem; Van Grootel, valerie. vangrootel@ulg. ac. be; Delrez, Laetitia;
Magain, Pierre; Burgasser, Adam; Demory, Brice-Olivier; Triaud,
Amaury; Queloz, Didier; Lederer, Sue
2016sptz.prop12126G Altcode:
The eclipsing binary nature of a nearby ultracool dwarf has just been
revealed. The aim of this DDT is to investigate this nearby system
further through high-precision infrared time-series photometry.
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Title: Analysis of luminosity distributions and the shape parameters
of strong gravitational lensing elliptical galaxies
Authors: Biernaux, J.; Magain, P.; Sluse, D.; Chantry, V.
2016A&A...585A..84B Altcode: 2015arXiv151009118B
Context. The luminosity profiles of galaxies acting as strong
gravitational lenses can be tricky to study. Indeed, strong
gravitational lensing images display several lensed components, both
point-like and diffuse, around the lensing galaxy. Those objects limit
the study of the galaxy luminosity to its inner parts. Therefore, the
usual fitting methods perform rather badly on such images. Previous
studies of strong lenses luminosity profiles using software such as
GALFIT or IMFITFITS and various PSF-determining methods have resulted
in somewhat discrepant results. <BR /> Aims: The present work aims at
investigating the causes of those discrepancies, as well as at designing
more robust techniques for studying the morphology of early-type
lensing galaxies with the ability to subtract a lensed signal from
their luminosity profiles. <BR /> Methods: We design a new method
to independently measure each shape parameter, namely, the position
angle, ellipticity, and half-light radius of the galaxy. Our half-light
radius measurement method is based on an innovative scheme for computing
isophotes that is well suited to measuring the morphological properties
of gravititational lensing galaxies. Its robustness regarding various
specific aspects of gravitational lensing image processing is analysed
and tested against GALFIT. It is then applied to a sample of systems
from the CASTLES database. <BR /> Results: Simulations show that, when
restricted to small, inner parts of the lensing galaxy, the technique
presented here is more trustworthy than GALFIT. It gives more robust
results than GALFIT, which shows instabilities regarding the fitting
region, the value of the Sérsic index, and the signal-to-noise
ratio. It is therefore better suited than GALFIT for gravitational
lensing galaxies. It is also able to study lensing galaxies that are
not much larger than the PSF. New values for the half-light radius
of the objects in our sample are presented and compared to previous
works. <P />Table 6 is only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/585/A84">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/585/A84</A>
---------------------------------------------------------
Title: TRAPPIST photometry and imaging monitoring of comet C/2013 R1
(Lovejoy): Implications for the origin of daughter species
Authors: Opitom, C.; Jehin, E.; Manfroid, J.; Hutsemékers, D.;
Gillon, M.; Magain, P.
2015A&A...584A.121O Altcode: 2015arXiv150701520O
We report the results of the narrow-band photometry and imaging
monitoring of comet C/2013 R1 (Lovejoy) with the robotic telescope
TRAPPIST (La Silla observatory). We gathered around 400 images
over 8 months pre- and post-perihelion between September 12, 2013
and July 6, 2014. We followed the evolution of the OH, NH, CN,
C<SUB>3</SUB>, and C<SUB>2</SUB> production rates computed with the
Haser model, as well as the evolution of the dust production. All
five gas species display an asymmetry about perihelion, since the
rate of brightening is steeper than the rate of fading. The study
of the coma morphology reveals gas and dust jets that indicate one
or several active zone(s) on the nucleus. The dust, C<SUB>2</SUB>,
and C<SUB>3</SUB> morphologies present some similarities, while
the CN morphology is different. OH and NH are enhanced in the tail
direction. The study of the evolution of the comet activity shows
that the OH, NH, and C<SUB>2</SUB> production rate evolution with the
heliocentric distance is correlated to the dust evolution. The CN and,
to a lesser extent, the C<SUB>3</SUB> do not display such a correlation
with the dust. This evidence and the comparison with parent species
production rates indicate that C<SUB>2</SUB> and C<SUB>3</SUB>,
on one hand, and OH and NH, on the other, could be - at least
partially - released from organic - rich grains and icy grains. On
the contrary, all evidences point to HCN being the main parent of CN
in this comet. <P />Appendix A is available in electronic form at <A
href="http://www.aanda.org/10.1051/0004-6361/201526427/olm">http://www.aanda.org</A>
---------------------------------------------------------
Title: Five years of comet narrow band photometry and imaging with
TRAPPIST
Authors: Opitom, Cyrielle; Jehin, Emmanuel; Manfroid, Jean;
Hutsemékers, Damien; Gillon, Michaël; Magain, Pierre
2015DPS....4750602O Altcode:
TRAPPIST is a 60-cm robotic telescope in La Silla Observatory [1]
mainly dedicated to the study of exoplanets and comets. The telescope
is equipped with a set of narrow band cometary filters designed by the
NASA for the Hale-Bopp observing campaign [2]. Since its installation in
2010, we gathered a high quality and homogeneous data set of more than
30 bright comets observed with narrow band filters. Some comets were
only observed for a few days but others have been observed weekly during
several months on both sides of perihelion. From the images, we derived
OH, NH, CN, C<SUB>2</SUB>, and C<SUB>3</SUB> production rates using a
Haser [3] model in addition to the Afρ parameter as a proxy for the
dust production. We computed production rates ratios and the dust color
for each comet to study their composition and followed the evolution
of these ratios and colors with the heliocentric distance.The TRAPPIST
data set, rich of more than 10000 images obtained and reduced in an
homogeneous way, allows us to address several fundamental questions
such as the pristine or evolutionary origin of composition differences
among comets. The evolution of comet activity with the heliocentric
distance, the differences between species, and from comet to comet, will
be discussed. Finally, the first results about the one year campaign on
comet C/2013 US10 (Catalina) and our recent work on the re-determination
of Haser scalelengths will be presented.[1] Jehin et al., The Messenger,
145, 2-6, 2011[2] Farnham et al., Icarus, 147, 180-204, 2000[3] Haser,
Bulletin de l’Académie Royal des Sciences de Belgique,63, 739, 1957
---------------------------------------------------------
Title: VizieR Online Data Catalog: Shape parameters of lensing
galaxies (Biernaux+, 2016)
Authors: Biernaux, J.; Magain, P.; Sluse, D.; Chantry, V.
2015yCat..35850084B Altcode:
In the paper we explain procedures designed to measure the position
angle, the ellipticity and the half-light radius of lensing galaxies,
that rely on an innovative scheme to compute isophotes. Table 6
details frame per frame the characteristics of the masks used in this
work. Those values are in fact the shape parameters of the galaxies,
before correcting from the effect of the PSF. The relative coordinates
of the galaxy center, with regards to a reference lensed image, and the
size of the region of interest are given as well. The reference lensed
image can be found in Fig. 2 in the paper and is the one labelled A
(or A1 in some cases). <P />(2 data files).
---------------------------------------------------------
Title: On the nature of cosmological time
Authors: Magain, Pierre; Hauret, Clémentine
2015arXiv150502052M Altcode:
Time is a parameter playing a central role in our most fundamental
modeling of natural laws. Relativity theory shows that the comparison
of times measured by different clocks depends on their relative
motions and on the strength of the gravitational field in which they
are embedded. In standard cosmology, the time parameter is the one
measured by fundamental clocks, i.e. clocks at rest with respect to the
expanding space. This proper time is assumed to flow at a constant rate
throughout the whole history of the Universe. We make the alternative
hypothesis that the rate at which cosmological time flows depends on the
dynamical state of the Universe. In thermodynamics, the arrow of time
is strongly related to the second law, which states that the entropy
of an isolated system will always increase with time or, at best,
stay constant. Hence, we assume that time measured by fundamental
clocks is proportional to the entropy of the region of the Universe
that is causally connected to them. Under that simple assumption, we
build a cosmological model that explains the Type Ia Supernovae data
(the best cosmological standard candles) without the need for exotic
dark matter nor dark energy.
---------------------------------------------------------
Title: TRAPPIST monitoring of comet C/2012 F6 (Lemmon)
Authors: Opitom, C.; Jehin, E.; Manfroid, J.; Hutsemékers, D.;
Gillon, M.; Magain, P.
2015A&A...574A..38O Altcode:
We report the results of the long-term narrowband photometry and
imaging monitoring of comet C/2012 F6 (Lemmon) with the robotic
TRAPPIST telescope (La Silla Observatory). Observations covered 52
nights pre- and post-perihelion between December 11, 2012, and June 11,
2013 (perihelion: 24 March, 2013). We followed the evolution of the OH,
NH, CN, C<SUB>3</SUB>, and C<SUB>2</SUB> production rates computed with
the Haser model as well as the evolution of the A(θ)fρ parameter
as a proxy for the dust production. All five gas species display
similar slopes for the heliocentric dependence. An asymmetry about
perihelion is observed, the rate of brightening being steeper than the
rate of fading. The chemical composition of the comet's coma changes
slightly along the orbit: the relative abundance of C<SUB>2</SUB>
to CN increases with the heliocentric distance (r) below -1.4 au
and decreases with r beyond 1.4 au while the C<SUB>3</SUB>-to-CN
ratio is constant during our observations. The behavior of the dust
is different from that of the gas, the slope of the heliocentric
dependence becoming steeper in early February, correlated to a change
in the visual lightcurve slope. However, the dust color does not
vary during the observations. The application of several enhancement
techniques on the images revealed structures in the CN, C<SUB>3</SUB>,
and C<SUB>2</SUB> images. These features imply the existence of one or
several active zone(s) on the comet nucleus. The shape of the structures
is similar in these three filters and changes from a roughly hourglass
shape in December and January to a corkscrew shape in February and
March. The structures in the continuum filters (sampling the dust)
are not correlated to those observed for the gas. During several full
nights in February, we observed changes in the CN and C<SUB>2</SUB>
structures that repeated periodically because of the nucleus rotation,
our derived rotational period being of 9.52 ± 0.05 h. <P />Full
Tables 2, 4, 6 are only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/574/A38">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/574/A38</A>
---------------------------------------------------------
Title: A global analysis of Spitzer and new HARPS data confirms the
loneliness and metal-richness of GJ 436 b
Authors: Lanotte, A. A.; Gillon, M.; Demory, B. -O.; Fortney, J. J.;
Astudillo, N.; Bonfils, X.; Magain, P.; Delfosse, X.; Forveille, T.;
Lovis, C.; Mayor, M.; Neves, V.; Pepe, F.; Queloz, D.; Santos, N.;
Udry, S.
2014A&A...572A..73L Altcode: 2014arXiv1409.4038L
Context. GJ 436b is one of the few transiting warm Neptunes for
which a detailed characterisation of the atmosphere is possible,
whereas its non-negligible orbital eccentricity calls for further
investigation. Independent analyses of several individual datasets
obtained with Spitzer have led to contradicting results attributed to
the different techniques used to treat the instrumental effects. <BR
/> Aims: We aim at investigating these previous controversial results
and developing our knowledge of the system based on the full Spitzer
photometry dataset combined with new Doppler measurements obtained
with the HARPS spectrograph. We also want to search for additional
planets. <BR /> Methods: We optimise aperture photometry techniques
and the photometric deconvolution algorithm DECPHOT to improve the
data reduction of the Spitzer photometry spanning wavelengths from
3-24 μm. Adding the high-precision HARPS radial velocity data, we
undertake a Bayesian global analysis of the system considering both
instrumental and stellar effects on the flux variation. <BR /> Results:
We present a refined radius estimate of R<SUB>P</SUB> = 4.10 ± 0.16
R<SUB>⊕</SUB> , mass M<SUB>P</SUB> = 25.4 ± 2.1 M<SUB>⊕</SUB>,
and eccentricity e = 0.162 ± 0.004 for <ASTROBJ>GJ 436b</ASTROBJ>. Our
measured transit depths remain constant in time and wavelength, in
disagreement with the results of previous studies. In addition, we find
that the post-occultation flare-like structure at 3.6 μm that led to
divergent results on the occultation depth measurement is spurious. We
obtain occultation depths at 3.6, 5.8, and 8.0 μm that are shallower
than in previous works, in particular at 3.6 μm. However, these
depths still appear consistent with a metal-rich atmosphere depleted in
methane and enhanced in CO/CO<SUB>2</SUB>, although perhaps less than
previously thought. We could not detect a significant orbital modulation
in the 8 μm phase curve. We find no evidence of a potential planetary
companion, stellar activity, or a stellar spin-orbit misalignment. <BR
/> Conclusions: Recent theoretical models invoking high-metallicity
atmospheres for warm Neptunes are a reasonable match to our results,
but we encourage new modelling efforts based on our revised data. Future
observations covering a wide wavelength range of GJ 436b and other
Neptune-class exoplanets will further illuminate their atmosphere
properties, whilst future accurate radial velocity measurements might
explain the eccentricity. <P />Based on observations made with the HARPS
spectrograph on the 3.6 m ESO telescope at the ESO La Silla Observatory,
Chile.Table 2 and Figs. 5-7 are available in electronic form at <A
href="http://www.aanda.org/10.1051/0004-6361/201424373/olm">http://www.aanda.org</A>
---------------------------------------------------------
Title: VizieR Online Data Catalog: TRAPPIST monitoring of comet
C/2012 F6 (Lemmon) (Opitom+, 2015)
Authors: Opitom, C.; Jehin, E.; Manfroid, J.; Hutsemekers, D.; Gillon,
M.; Magain, P.
2014yCat..35740038O Altcode: 2014yCat..35749038O
Observational circumstances, OH, NH, CN, C<SUB>3 and C</SUB>2 production
and A(θ)f<SUB>{rho}</SUB> values of comet C/2012 F6 (Lemmon) obtained
using the TRAPPIST telescope <P />(3 data files).
---------------------------------------------------------
Title: Search for a habitable terrestrial planet transiting the
nearby red dwarf GJ 1214
Authors: Gillon, M.; Demory, B. -O.; Madhusudhan, N.; Deming, D.;
Seager, S.; Zsom, A.; Knutson, H. A.; Lanotte, A. A.; Bonfils, X.;
Désert, J. -M.; Delrez, L.; Jehin, E.; Fraine, J. D.; Magain, P.;
Triaud, A. H. M. J.
2014A&A...563A..21G Altcode: 2013arXiv1307.6722G
High-precision eclipse spectrophotometry of transiting terrestrial
exoplanets represents a promising path for the first atmospheric
characterizations of habitable worlds and the search for life outside
our solar system. The detection of terrestrial planets transiting nearby
late-type M-dwarfs could make this approach applicable within the
next decade, with soon-to-come general facilities. In this context,
we previously identified GJ 1214 as a high-priority target for a
transit search, as the transit probability of a habitable planet
orbiting this nearby M4.5 dwarf would be significantly enhanced by
the transiting nature of GJ 1214 b, the super-Earth already known
to orbit the star. Based on this observation, we have set up an
ambitious high-precision photometric monitoring of GJ 1214 with the
Spitzer Space Telescope to probe the inner part of its habitable zone
in search of a transiting planet as small as Mars. We present here
the results of this transit search. Unfortunately, we did not detect
any other transiting planets. Assuming that GJ 1214 hosts a habitable
planet larger than Mars that has an orbital period smaller than 20.9
days, our global analysis of the whole Spitzer dataset leads to an a
posteriori no-transit probability of ~98%. Our analysis allows us to
significantly improve the characterization of GJ 1214 b, to measure its
occultation depth to be 70 ± 35 ppm at 4.5 μm, and to constrain it
to be smaller than 205 ppm (3σ upper limit) at 3.6 μm. In agreement
with the many transmission measurements published so far for GJ 1214 b,
these emission measurements are consistent with both a metal-rich and a
cloudy hydrogen-rich atmosphere. <P />The photometric time series used
in this work are only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/563/A21">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/563/A21</A>
---------------------------------------------------------
Title: VizieR Online Data Catalog: GJ 1214 Trappist and Spitzer
light curves (Gillon+, 2014)
Authors: Gillon, M.; Deming, D.; Madhusudhan, N.; Deming, D.; Seager,
S.; Zsom, A.; Knutson, H. A.; Lanotte, A. A.; Bonfils, X.; Desert,
J. -M.; Delrez, L.; Jehin, E.; Fraine, J. D.; Magain, P.; Triaud,
A. H. M. J.
2014yCat..35630021G Altcode: 2014yCat..35639021G
Files trappist.dat, spitzer1.dat, and spitzer2.dat contain the
photometric time-series presented in the paper and obtained by the
TRAPPIST and Spitzer telescopes. <P />(3 data files).
---------------------------------------------------------
Title: TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope)
Authors: Jehin, E.; Gillon, M.; Opitom, C.; Manfroid, J.; Hutsemékers,
D.; Magain, P.
2013EPSC....8..968J Altcode:
TRAPPIST is a 60-cm robotic telescope that has been installed in June
2010 at the ESO La Silla Observatory [1]. Operated from Liège (Belgium)
it is devoted to the detection and characterisation of exoplanets and
to the study of comets and other small bodies in the Solar System. We
describe here the hardware and the goals of the project and give an
overview of the comet production rates monitoring after three years
of operations.
---------------------------------------------------------
Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational
Lenses. XIV. Time delay of the doubly lensed quasar SDSS J1001+5027
Authors: Rathna Kumar, S.; Tewes, M.; Stalin, C. S.; Courbin, F.;
Asfandiyarov, I.; Meylan, G.; Eulaers, E.; Prabhu, T. P.; Magain,
P.; Van Winckel, H.; Ehgamberdiev, Sh.
2013A&A...557A..44R Altcode: 2013arXiv1306.5105R
This paper presents optical R-band light curves and the time delay of
the doubly imaged gravitationally lensed quasar SDSS J1001+5027 at a
redshift of 1.838. We have observed this target for more than six years,
between March 2005 and July 2011, using the 1.2-m Mercator Telescope,
the 1.5-m telescope of the Maidanak Observatory, and the 2-m Himalayan
Chandra Telescope. Our resulting light curves are composed of 443
independent epochs, and show strong intrinsic quasar variability, with
an amplitude of the order of 0.2 magnitudes. From this data, we measure
the time delay using five different methods, all relying on distinct
approaches. One of these techniques is a new development presented in
this paper. All our time-delay measurements are perfectly compatible. By
combining them, we conclude that image A is leading B by 119.3 ±
3.3 days (1σ, 2.8% uncertainty), including systematic errors. It has
been shown recently that such accurate time-delay measurements offer a
highly complementary probe of dark energy and spatial curvature, as they
independently constrain the Hubble constant. The next mandatory step
towards using SDSS J1001+5027 in this context will be the measurement
of the velocity dispersion of the lensing galaxy, in combination with
deep Hubble Space Telescope imaging. <P />Based on observations made
with the 2.0-m Himalayan Chandra Telescope (Hanle, India), the 1.5-m
AZT-22 telescope (Maidanak Observatory, Uzbekistan), and the 1.2-m
Mercator Telescope. Mercator is operated on the island of La Palma
by the Flemish Community, at the Spanish Observatorio del Roque de
los Muchachos of the Instituto de Astrofísica de Canarias.Light
curves are only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/557/A44">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/557/A44</A>
---------------------------------------------------------
Title: TRAPPIST monitoring of comet C/2012 F6 (Lemmon)
Authors: Opitom, C.; Jehin, E.; Manfroid, J.; Hutsemékers, D.;
Gillon, M.; Magain, P.
2013EPSC....8..764O Altcode:
Comet C/2012 F6 is a long-period comet that reached perihelion on March
23, 2012. The unexpected brightness of this comet since December 2012
allowed us to obtain narrowband photometry and to study its chemical
composition as well as its rotation.
---------------------------------------------------------
Title: Herschel imaging and spectroscopy of the nebula around the
luminous blue variable star WRAY 15-751
Authors: Vamvatira-Nakou, C.; Hutsemékers, D.; Royer, P.; Nazé,
Y.; Magain, P.; Exter, K.; Waelkens, C.; Groenewegen, M. A. T.
2013A&A...557A..20V Altcode: 2013arXiv1307.0759V
We have obtained far-infrared Herschel-PACS imaging and spectroscopic
observations of the nebular environment of the luminous blue variable
(LBV) WRAY 15-751. The far-infrared images clearly show that the main,
dusty nebula is a shell of radius 0.5 pc and width 0.35 pc extending
outside the Hα nebula. Furthermore, these images reveal a second,
bigger and fainter dust nebula that is observed for the first time. Both
nebulae lie in an empty cavity, very likely the remnant of the O-star
wind bubble formed when the star was on the main sequence. The kinematic
ages of the nebulae are calculated to be about 2 × 10<SUP>4</SUP> and
8 × 10<SUP>4</SUP> years, and we estimated that each nebula contains
~0.05 M<SUB>⊙</SUB> of dust. Modeling of the inner nebula indicates
a Fe-rich dust. The far-infrared spectrum of the main nebula revealed
forbidden emission lines coming from ionized and neutral gas. Our
study shows that the main nebula consists of a shell of ionized
gas surrounded by a thin photodissociation region illuminated by an
"average" early-B star. We derive the abundance ratios N/O = 1.0 ±
0.4 and C/O = 0.4 ± 0.2, which indicate a mild N/O enrichment. From
both the ionized and neutral gas components we estimate that the inner
shell contains 1.7 ± 0.6 M<SUB>⊙</SUB> of gas. Assuming a similar
dust-to-gas ratio for the outer nebula, the total mass ejected by WRAY
15-751 amounts to 4 ± 2 M<SUB>⊙</SUB>. The measured abundances,
masses and kinematic ages of the nebulae were used to constrain
the evolution of the star and the epoch at which the nebulae were
ejected. Our results point to an ejection of the nebulae during the
red super-giant (RSG) evolutionary phase of an ~40 M<SUB>⊙</SUB>
star. The multiple shells around the star suggest that the mass-loss
was not a continuous ejection but rather a series of episodes of
extreme mass-loss. Our measurements are compatible with the recent
evolutionary tracks computed for an ~40 M<SUB>⊙</SUB> star with
little rotation. They support the O-BSG-RSG-YSG-LBV filiation and the
idea that high-luminosity and low-luminosity LBVs follow different
evolutionary paths. <P />Herschel is an ESA space observatory with
science instruments provided by European-led Principal Investigator
consortia and with important participation from NASA.Based in part
on observations collected at the European Southern Observatory, La
Silla, Chile.
---------------------------------------------------------
Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational
Lenses. XIII. Time delays and 9-yr optical monitoring of the lensed
quasar RX J1131-1231
Authors: Tewes, M.; Courbin, F.; Meylan, G.; Kochanek, C. S.; Eulaers,
E.; Cantale, N.; Mosquera, A. M.; Magain, P.; Van Winckel, H.; Sluse,
D.; Cataldi, G.; Vörös, D.; Dye, S.
2013A&A...556A..22T Altcode: 2012arXiv1208.6009T
We present the results from nine years of optically monitoring the
gravitationally lensed z<SUB>QSO</SUB> = 0.658 quasar RX J1131-1231. The
R-band light curves of the four individual images of the quasar
were obtained using deconvolution photometry for a total of 707
epochs. Several sharp quasar variability features strongly constrain the
time delays between the quasar images. Using three different numerical
techniques, we measured these delays for all possible pairs of quasar
images while always processing the four light curves simultaneously. For
all three methods, the delays between the three close images A, B,
and C are compatible with being 0, while we measured the delay of
image D to be 91 days, with a fractional uncertainty of 1.5% (1σ),
including systematic errors. Our analysis of random and systematic
errors accounts in a realistic way for the observed quasar variability,
fluctuating microlensing magnification over a broad range of temporal
scales, noise properties, and seasonal gaps. Finally, we find that our
time-delay measurement methods yield compatible results when applied
to subsets of the data. <P />Based on observations made with the 1.2-m
Swiss Euler telescope (La Silla, Chile), the 1.3-m SMARTS telescope (Las
Campanas, Chile), and the 1.2-m Mercator Telescope. Mercator is operated
on the island of La Palma by the Flemish Community, at the Spanish
Observatorio del Roque de los Muchachos of the Instituto de Astrofísica
de Canarias.Light curves are available at the CDS via anonymous ftp to
<A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/556/A22">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/556/A22</A>
---------------------------------------------------------
Title: Fast-evolving weather for the coolest of our two new substellar
neighbours
Authors: Gillon, M.; Triaud, A. H. M. J.; Jehin, E.; Delrez, L.;
Opitom, C.; Magain, P.; Lendl, M.; Queloz, D.
2013A&A...555L...5G Altcode: 2013arXiv1304.0481G
We present the results of intense photometric monitoring in the
near-infrared (~0.9 μm) with the TRAPPIST robotic telescope of
the newly discovered binary brown dwarf WISE J104915.57-531906.1,
the third closest system to the Sun at a distance of only 2 pc. Our
twelve nights of time-series photometry reveal a quasi-periodic (P =
4.87 ± 0.01h) variability with a maximum peak-peak amplitude of ~11%
and strong night-to-night evolution. We attribute this variability
to the rotational modulation of fast-evolving weather patterns in
the atmosphere of the coolest component (~T1-type) of the binary. No
periodic signal is detected for the hottest component (~L8-type). For
both brown dwarfs, our data allow us to firmly discard any unique
transit during our observations for planets ≥2 R<SUB>⊕</SUB>. For
orbital periods smaller than ~9.5 h, transiting planets are excluded
down to an Earth-size.
---------------------------------------------------------
Title: SPECULOOS: Search for habitable Planets EClipsing ULtra-cOOl
Stars
Authors: Gillon, Michaël; Jehin, Emmanuël; Delrez, Laetitia; Magain,
Pierre; Opitom, Cyrielle; Sohy, Sandrine
2013prpl.conf2K066G Altcode:
The 1000 nearest ultra-cool stars (spectral type M6 and latter)
represent a unique opportunity for the search for life outside our
solar system. Due to their small luminosity, their habitable zone is
30-100 times closer than for the Sun, the corresponding orbital periods
ranging from one to a few days. Thanks to this proximity, the transits
of a habitable planet are much more probable and frequent than for
an Earth-Sun analog, while their tiny size (about 1 Jupiter radius)
leads to transits deep enough for a ground-based detection, even for
sub-Earth size planets. Furthermore, a habitable planet transiting
one of these nearby ultra-cool stars would be amenable for a thorough
atmospheric characterization, including the detection of possible
biosignatures, notably with the near-to-come JWST. Motivated by these
reasons, we have set up the concept of a ground-based survey optimized
for detecting planets of Earth-size and below transiting the nearest
Southern ultra-cool stars. We present here this concept and its status.
---------------------------------------------------------
Title: VizieR Online Data Catalog: The doubly lensed quasar SDSS
J1001+5027 (Rathna Kumar+, 2013)
Authors: Rathna, Kumar S.; Tewes, M.; Stalin, C. S.; Courbin, F.;
Asfandiyarov, I.; Meylan, G.; Eulaers, E.; Prabhu, T. P.; Magain,
P.; van Winckel, H.; Ehgamberdiev, Sh.
2013yCat..35570044R Altcode: 2013yCat..35579044R
These data are R-band light curves of the doubly lensed quasar SDSS
J1001+5027, as displayed in Fig. 4 of the paper. They cover 6.5 years,
from March 2005 to July 2011. <P />The light curves are obtained using
deconvolution photometry of images from 3 different telescopes, for
a total of 443 epochs. Several quasar variability features strongly
constrain the time delay between the quasar images. <P />(1 data file).
---------------------------------------------------------
Title: VizieR Online Data Catalog: R-band light curves of RX
J1131-1231 (Tewes+, 2013)
Authors: Tewes, M.; Courbin, F.; Meylan, G.; Kochanek, C. S.; Eulaers,
E.; Cantale, N.; Mosquera, A. M.; Magain, P.; van Winckel, H.; Sluse,
D.; Cataldi, G.; Voros, D.; Dye, S.
2013yCat..35560022T Altcode: 2013yCat..35569022T
We have been monitoring the quadruply lensed quasar RX J1131-1231 since
December 2003 with different telescopes in the R band (~600-720nm). The
resulting R-band light curves of the quadruply lensed quasar RX
J1131-1231, is displayed in Fig. 4 of the paper. <P />The light
curves are obtained using deconvolution photometry of images from 3
different telescopes (the ESO Euler 1.2m, the CTIO SMARTS 1.3m and
the Mercator 1.2m), for a total of 707 epochs. Several sharp quasar
variability features strongly constrain the time delays between the
quasar images. <P />(1 data file).
---------------------------------------------------------
Title: The Nebula around the Luminous Blue Variable WRAY 15-751 as
seen by Herschel
Authors: Vamvatira-Nakou, C.; Hutsemekers, D.; Royer, P.; Naze, Y.;
Magain, P.; Exter, K.; Waelkens, C.; Groenewegen, M.
2013msao.confE.188V Altcode:
To understand the evolution of massive stars it is crucial to study the
nebulae associated to Luminous Blue Variables which can reveal the star
mass-loss history. We obtained far-infrared Herschel PACS imaging and
spectroscopic observations of the nebula associated with the Luminous
Blue Variable star WRAY 15-751. These images revealed a second nebula,
bigger and cooler, lying in an empty cavity that probably delineates
the remnant of the O-star bubble formed when the star was on the Main
Sequence. The dust mass and temperature were derived from the modeling
of the far-infrared SED. The analysis of the emission line spectrum
revealed that the main nebula consists of a region of photoionised
gas surrounded by a thin photodissociation region. Both regions are
mixed with dust. The calculated C, N, O abundances, together with the
estimated mass-loss rate, show that the nebula was ejected from the
star during a Red Supergiant phase. This is compatible with the latest
evolutionary tracks for a ~40 Mo star with little rotation.
---------------------------------------------------------
Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational
Lenses. XII. Time delays of the doubly lensed quasars SDSS J1206+4332
and HS 2209+1914
Authors: Eulaers, E.; Tewes, M.; Magain, P.; Courbin, F.; Asfandiyarov,
I.; Ehgamberdiev, Sh.; Rathna Kumar, S.; Stalin, C. S.; Prabhu, T. P.;
Meylan, G.; Van Winckel, H.
2013A&A...553A.121E Altcode: 2013arXiv1304.4474E
<BR /> Aims: Within the framework of the COSMOGRAIL collaboration we
present 7- and 8.5-year-long light curves and time-delay estimates
for two gravitationally lensed quasars: SDSS J1206+4332 and HS
2209+1914. <BR /> Methods: We monitored these doubly lensed quasars in
the R-band using four telescopes: the Mercator, Maidanak, Himalayan
Chandra, and Euler telescopes, together spanning a period of 7 to
8.5 observing seasons from mid-2004 to mid-2011. The photometry of
the quasar images was obtained through simultaneous deconvolution of
these data. The time delays were determined from these resulting light
curves using four very different techniques: a dispersion method, a
spline fit, a regression difference technique, and a numerical model
fit. This minimizes the bias that might be introduced by the use of
a single method. <BR /> Results: The time delay for SDSS J1206+4332
is Δt<SUB>AB</SUB> = 111.3 ± 3 days with A leading B, confirming a
previously published result within the error bars. For HS 2209+1914
we present a new time delay of Δt<SUB>BA</SUB> = 20.0 ± 5 days with
B leading A. <BR /> Conclusions: The combination of data from up to
four telescopes have led to well-sampled and nearly 9-season-long
light curves, which were necessary to obtain these results,
especially for the compact doubly lensed quasar HS 2209+1914. <P
/>Based on observations made with the 1.2-m Swiss Euler telescope
(La Silla, Chile), the 1.5-m AZT-22 telescope (Maidanak Observatory,
Uzbekistan), the 2.0-m HCT telescope (Hanle, India), and the 1.2-m
Mercator Telescope. Mercator is operated on the island of La Palma by
the Flemish Community, at the Spanish Observatorio del Roque de los
Muchachos of the Instituto de Astrofísica de Canarias.Numerical values
of light curves are only available at the CDS via anonymous ftp to
<A href="http://cdsarc.u-strasbg.fr">cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/553/A121">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/553/A121</A>
and at <A href="http://www.cosmograil.org">http://www.cosmograil.org</A>
---------------------------------------------------------
Title: VizieR Online Data Catalog: 2 lensed quasars light curves
(Eulaers+, 2013)
Authors: Eulaers, E.; Tewes, M.; Magain, P.; Courbin, F.; Asfandiyarov,
I.; Ehgamberdiev, Sh.; Rathna, Kumar S.; Stalin, C. S.; Prabhu, T. P.;
Meylan, G.; van Winckel, H.
2013yCat..35530121E Altcode: 2013yCat..35539121E
Within the framework of the COSMOGRAIL collaboration we present 7-
and 8.5-year-long light curves and time-delay estimates for two
gravitationally lensed quasars: SDSS J1206+4332 and HS 2209+1914. <P
/>We monitored these doubly lensed quasars in the R-band using four
telescopes: the Mercator, Maidanak, Himalayan Chandra, and Euler
Telescopes, together spanning a period of 7 to 8.5 observing seasons
from mid-2004 to mid-2011. The photometry of the quasar images was
obtained through simultaneous deconvolution of these data. The time
delays were determined from these resulting light curves using four very
different techniques: a dispersion method, a spline fit, a regression
difference technique, and a numerical model fit. This minimizes the
bias that might be introduced by the use of a single method. <P />(2
data files).
---------------------------------------------------------
Title: TRAPPIST-UCDTS: A prototype search for habitable planets
transiting ultra-cool stars
Authors: Gillon, M.; Jehin, E.; Fumel, A.; Magain, P.; Queloz, D.
2013EPJWC..4703001G Altcode:
The ∼1000 nearest ultra-cool stars (spectral type M6 and latter)
represent a unique opportunity for the search for life outside solar
system. Due to their small luminosity, their habitable zone is 30-100
times closer than for the Sun, the corresponding orbital periods
ranging from one to a few days. Thanks to this proximity, the transits
of a habitable planet are much more probable and frequent than for an
Earth-Sun analog, while their tiny size (∼1 Jupiter radius) leads to
transits deep enough for a ground-based detection, even for sub-Earth
size planets. Furthermore, a habitable planet transiting one of these
nearby ultra-cool star would be amenable for a thorough atmospheric
characterization, including the detection of possible biosignatures,
notably with the near-to-come JWST. Motivated by these reasons, we have
set up the concept of a ground-based survey optimized for detecting
planets of Earth-size and below transiting the nearest Southern
ultra-cool stars. To assess thoroughly the actual potential of this
future survey, we are currently conducting a prototype mini-survey using
the TRAPPIST robotic 60cm telescope located at La Silla ESO Observatory
(Chile). We summarize here the preliminary results of this mini-survey
that fully validate our concept.
---------------------------------------------------------
Title: Gravitational lensing evidence against extended dark matter
halos
Authors: Magain, Pierre; Chantry, Virginie
2013arXiv1303.6896M Altcode:
It is generally thought that galaxies are embedded in dark matter
halos extending well beyond their luminous matter. The existence of
these galactic halos is mainly derived from the larger than expected
velocities of stars and gas in the outskirts of spiral galaxies. Much
less is known about dark matter around early-type (elliptical or
lenticular) galaxies. We use gravitational lensing to derive the masses
of early-type galaxies deflecting light of background quasars. This
provides a robust measurement of the total mass within the Einstein
ring, a circle whose diameter is comparable to the separation of the
different quasar images. We find that the mass-to-light ratio of the
lensing galaxies does not depend on radius, from inner galactic regions
out to several half-light radii. Moreover, its value does not exceed the
value predicted by stellar population models by more than a factor two,
which may be explained by baryonic dark matter alone, without any need
for exotic matter. Our results thus suggest that, if dark matter is
present in early-type galaxies, its amount does not exceed the amount
of luminous matter and its density follows that of luminous matter, in
sharp contrast to what is found from rotation curves of spiral galaxies.
---------------------------------------------------------
Title: COSMOGRAIL: Time delays in lensed quasars from Himalayan
Chandra Telescope
Authors: Rathna Kumar, S.; Stalin, C. S.; Tewes, M.; Courbin, F.;
Asfandiyarov, I.; Ibrahimov, M.; Eulaers, E.; Meylan, G.; Prabhu,
T. P.; Magain, P.
2013ASInC...9...87R Altcode:
Estimating H_0 to an accuracy of few percent is an important
challenge today as it will offer key insights into various questions
in cosmology. By measuring time delays between the photometric
variations in lensed quasar images and subsequent modelling of the
mass distribution in the lensing galaxy, it is possible to constrain
H_0 in a way well complementary to traditional techniques. Time delays
are difficult to measure due to the long time span needed to monitor
the sources and photometry is challenging due to the small angular
separation between the lensed quasar images. These issues are addressed
by the COSMOGRAIL (COSmological MOnitoring of GRAvItational Lenses)
collaboration, which uses several telescopes in both the hemispheres
to monitor a large sample of gravitationally lensed quasars. As part
of this collaboration, 6 sources are being monitored using the 2 m
Himalayan Chandra Telescope (HCT) in Hanle, India. We present here
the preliminary estimates of time delays in these sources.
---------------------------------------------------------
Title: COSMOGRAIL: Measuring Time Delays of Gravitationally Lensed
Quasars to Constrain Cosmology
Authors: Tewes, M.; Courbin, F.; Meylan, G.; Kochanek, C. S.; Eulaers,
E.; Cantale, N.; Mosquera, A. M.; Asfandiyarov, I.; Magain, P.; van
Winckel, H.; Sluse, D.; Keerthi, R. K. S.; Stalin, C. S.; Prabhu,
T. P.; Saha, P.; Dye, S.
2012Msngr.150...49T Altcode:
COSMOGRAIL is a long-term programme for the photometric monitoring
of gravitationally lensed quasars. It makes use of several
medium-size telescopes to derive long and well-sampled light curves
of lensed quasars, in order to measure the time delays between
the quasar images. These delays directly relate to the Hubble
constant H<SUB>0</SUB>, without any need for secondary distance
calibrations. COSMOGRAIL was initiated in 2004, and has now secured
almost a decade of data, resulting in cosmological constraints that
are very complementary to other cosmological probes.
---------------------------------------------------------
Title: An expanding universe without dark matter and dark energy
Authors: Magain, Pierre
2012arXiv1212.1110M Altcode:
Assuming that observers located inside the Universe measure a time flow
which is different from the time appearing in the Friedmann-Lemaitre
equation, and determining this time flow such that the Universe always
appears flat to these observers, we derive a simple cosmological model
which allows to explain the velocity dispersions of galaxies in galaxy
clusters without introducing dark matter. It also solves the horizon
problem without recourse to inflation. Moreover, it explains the present
acceleration of the expansion without any resort to dark energy and
provides a good fit to the observations of distant supernovae. Depending
on the present value of the matter-energy density, we calculate an
age of the Universe between 15.4 and 16.5 billion years, significantly
larger than the 13.7 billion years of the standard Lambda-CDM model. Our
model has a slower expansion rate in the early epochs, thus leaving
more time for the formation of structures such as stars and galaxies.
---------------------------------------------------------
Title: Minor Planet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2012MPC..81457..12J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Debris disks as seen by Herschel/DUNES
Authors: Löhne, T.; Eiroa, C.; Augereau, J. -C.; Ertel, S.; Marshall,
J. P.; Mora, A.; Absil, O.; Stapelfeldt, K.; Thébault, P.; Bayo, A.;
del Burgo, C.; Danchi, W.; Krivov, A. V.; Lebreton, J.; Letawe, G.;
Magain, P.; Maldonado, J.; Montesinos, B.; Pilbratt, G. L.; White,
G. J.; Wolf, S.
2012AN....333..441L Altcode:
The far-infrared excesses produced by debris disks are common features
of stellar systems. These disks are thought to contain solids ranging
from micron-sized dust to planetesimals. Naturally, their formation
and evolution are linked to those of potential planets. With this
motivation, the Herschel open time key programme DUNES (DUst around
NEarby Stars) aims at further characterising known debris disks and
discovering new ones in the regime explored by the Herschel space
observatory. On the one hand, in their survey of 133 nearby FGK stars,
DUNES discovered a class of extremely cold and faint debris disks,
different from well-known disks such as the one around Vega in that
their inferred typical grain sizes are rather large, indicating
low dynamical excitation and low collision rates. On the other
hand, for the more massive disk around the sun-like star HD 207129,
well-resolved PACS images confirmed the ring-liked structure seen in
HST images and provided valuable information for an in-depth study and
benchmark for models. Employing both models for power-law fitting and
collisional evolution we found the disk around HD 207129 to feature
low collision rates and large grains, as well. Transport by means
of Poynting-Robertson drag likely plays a role in replenishing the
dust seen closer to the star, inside of the ring. The inner edge is
therefore rather smooth and the contribution from the extended halo of
barely bound grains is small. Both slowly self-stirring and planetary
perturbations could potentially have formed and shaped this disk. <P
/>Herschel is an ESA space observatory with science instruments provided
by European-led Principal Investigator consortia and with important
participation from NASA.
---------------------------------------------------------
Title: The TRAPPIST survey of southern transiting planets. I. Thirty
eclipses of the ultra-short period planet WASP-43 b
Authors: Gillon, M.; Triaud, A. H. M. J.; Fortney, J. J.; Demory,
B. -O.; Jehin, E.; Lendl, M.; Magain, P.; Kabath, P.; Queloz, D.;
Alonso, R.; Anderson, D. R.; Collier Cameron, A.; Fumel, A.; Hebb, L.;
Hellier, C.; Lanotte, A.; Maxted, P. F. L.; Mowlavi, N.; Smalley, B.
2012A&A...542A...4G Altcode: 2012arXiv1201.2789G
We present twenty-three transit light curves and seven occultation
light curves for the ultra-short period planet WASP-43 b, in addition
to eight new measurements of the radial velocity of the star. Thanks to
this extensive data set, we improve significantly the parameters of the
system. Notably, the largely improved precision on the stellar density
(2.41 ± 0.08 ρ<SUB>⊙</SUB>) combined with constraining the age
to be younger than a Hubble time allows us to break the degeneracy
of the stellar solution mentioned in the discovery paper. The
resulting stellar mass and size are 0.717 ± 0.025 M<SUB>⊙</SUB>
and 0.667 ± 0.011 R<SUB>⊙</SUB>. Our deduced physical parameters
for the planet are 2.034 ± 0.052 M<SUB>Jup</SUB> and 1.036 ± 0.019
R<SUB>Jup</SUB>. Taking into account its level of irradiation, the high
density of the planet favors an old age and a massive core. Our deduced
orbital eccentricity, 0.0035<SUB>-0.0025</SUB><SUP>+0.0060</SUP>, is
consistent with a fully circularized orbit. We detect the emission of
the planet at 2.09 μm at better than 11-σ, the deduced occultation
depth being 1560 ± 140 ppm. Our detection of the occultation at 1.19
μm is marginal (790 ± 320 ppm) and more observations are needed
to confirm it. We place a 3-σ upper limit of 850 ppm on the depth
of the occultation at ~0.9 μm. Together, these results strongly
favor a poor redistribution of the heat to the night-side of the
planet, and marginally favor a model with no day-side temperature
inversion. <P />Based on data collected with the TRAPPIST and
Euler telescopes at ESO La Silla Observatory, Chile, and with the
VLT/HAWK-I instrument at ESO Paranal Observatory, Chile (program
086.C-0222).Tables 1 and 4 are available in electronic form at <A
href="http://www.aanda.org">http://www.aanda.org</A>Photometry
is only available at the CDS via anonymous ftp
to cdsarc.u-strasbg.fr (130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/542/A4">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/542/A4</A>
---------------------------------------------------------
Title: VizieR Online Data Catalog: WASP-43b thirty eclipses (Gillon+,
2012)
Authors: Gillon, M.; Triaud, A. H. M. J.; Fortney, J. J.; Demory,
B. -O.; Jehin, E.; Lendl, M.; Magain, P.; Kabath, P.; Queloz, D.;
Alonso, R.; Anderson, D. R.; Collier, Cameron A.; Fumel, A.; Hebb, L.;
Hellier, C.; Lanotte, A.; Maxted, P. F. L.; Mowlavi, N.; Smalley, B.
2012yCat..35420004G Altcode: 2012yCat..35429004G
We present photometric time-series obtained by the TRAPPIST, Euler
and VLT telescopes. <P />(4 data files).
---------------------------------------------------------
Title: Minor Planet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2012MPC..79337...9J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Minor Planet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2012MPC..79015...3J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Comet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2012MPC..78279..27J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Minor Planet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2012MPC..78580...7J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational
Lenses. X. Modeling based on high-precision astrometry of a sample
of 25 lensed quasars: consequences for ellipticity, shear, and
astrometric anomalies
Authors: Sluse, D.; Chantry, V.; Magain, P.; Courbin, F.; Meylan, G.
2012A&A...538A..99S Altcode: 2011arXiv1112.0005S
Gravitationally lensed quasars can be used as powerful cosmological and
astrophysical probes. We can (i) infer the Hubble constant H<SUB>0</SUB>
based on the so-called time-delay technique, (ii) unveil substructures
along the line-of-sight toward distant galaxies, and (iii) compare the
shape and the slope of baryons and dark matter distributions in the
inner regions of galaxies. To reach these goals, we need high-accuracy
astrometry of the quasar images relative to the lensing galaxy and
morphology measurements of the lens. In this work, we first present
new astrometry for 11 lenses with measured time delays, namely,
JVAS B0218+357, SBS 0909+532, RX J0911.4+0551, FBQS J0951+2635, HE
1104-1805, PG 1115+080, JVAS B1422+231, SBS 1520+530, CLASS B1600+434,
CLASS B1608+656, and HE 2149-2745. These measurements proceed from
the use of the Magain-Courbin-Sohy (MCS) deconvolution algorithm
applied in an iterative way (ISMCS) to near-IR HST images. We obtain a
typical astrometric accuracy of about 1-2.5 mas and an accurate shape
measurement of the lens galaxy. Second, we combined these measurements
with those of 14 other lensing systems, mostly from the COSMOGRAIL set
of targets, to present new mass models of these lenses. The modeling
of these 25 gravitational lenses led to the following results: 1)
in four double-image quasars (HE0047-1746, J1226-006, SBS 1520+530,
and HE 2149-2745), we show that the influence of the lens environment
on the time delay can easily be quantified and modeled, hence putting
these lenses with high priority for time-delay determination; 2)
for quadruple-image quasars, the difficulty often encountered in
reproducing the image positions to milli-arcsec accuracy (astrometric
anomaly problem) is overcome by explicitly including the nearest visible
galaxy/satellite in the lens model. However, one anomalous system
(RXS J1131-1231) does not show any luminous perturber in its vicinity,
and three others (WFI 2026-4536, WFI 2033-4723, and B2045+265) have
problematic modeling. These four systems are the best candidates for
a pertubation by a dark matter substructure along the line-of-sight;
3) we revisit the correlation between the position angle (PA) and
ellipticity of the light and of the mass distribution in lensing
galaxies. As in previous studies, we find a significant correlation
between the PA of the light and of the mass distributions. However, in
contrast with these same studies, we find that the ellipticity of the
light and of the mass also correlate well, suggesting that the overall
spatial distribution of matter is not very different from the baryon
distribution in the inner ~5 kpc of lensing galaxies. This offers a
new test for high-resolution hydrodynamical simulations. <P />Based
on observations made with the NASA/ESA HST Hubble Space Telescope by
the CfA-Arizona Space Telescope Lens Survey (CASTLeS) collaboration,
obtained from the data archive at the Space Science Institute, which
is operated by AURA, the Association of Universities for Research in
Astronomy, Inc., under NASA contract NAS-5-26555.
---------------------------------------------------------
Title: Comet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2012MPC..77877..22J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Minor Planet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2012MPC..78177...3J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observations and Orbits of Comets
Authors: Kostov, A.; Vassileva, L.; Vales, J.; Gajdos, S.; Vilagi, J.;
Foglia, S.; Galli, G.; Buzzi, L.; Naves, R.; Campas, M.; Ligustri,
R.; Abe, H.; Seki, T.; Bill, H.; Arnold, L.; Kelemen, J.; Micheli,
M.; Elliott, G. T.; Tholen, D. J.; Baransky, A.; Hergenrother, C. W.;
Gibbs, A. R.; Ahern, J. D.; Beshore, E. C.; Boattini, A.; Garradd,
G. J.; Tricarico, P.; Grauer, A. D.; Hill, R. E.; Kowalski, R. A.;
Larson, S. M.; McNaught, R. H.; Blythe, M.; Spitz, G.; Brungard,
R.; Paige, J.; Festler, P.; McVey, T.; Valdivia, A.; Gall, C.;
Melita, M. D.; Durig, D. T.; Liu, H.; Ikari, Y.; Castellano, J.;
Dupouy, P.; Jaeger, M.; Prosperi, E.; Vollmann, W.; Andreev, M.;
Emelyanenko, V.; Sergeev, A.; Parakhin, N.; Kozlov, V.; Karpov, N.;
Nevski, V.; Nicolas, J.; Lopesino, J.; Borghini, W.; Bosch, J. M.;
Olivera, R. M.; Martignoni, M.; Bryssinck, E.; Diepvens, A.; Gerke,
V.; Plaksa, S.; Novichonok, A.; Chestnov, D.; Xu, Z.; Gao, X.; Grau
Horta, F.; Gaitan, J.; Brusa, M.; Sempio, L.; Ohshima, Y.; Sugiyama,
Y.; Hills, K.; Yusa, T.; Koshikawa, M.; Takahashi, T.; Primak, N.;
Schultz, A.; Watters, S.; Thiel, J.; Goggia, T.; Dymock, R.; Sato, H.;
Guido, E.; Sostero, G.; Howes, N.; Kiyota, S.; Haugh, T.; Sherrod,
P. C.; Bell, C.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers,
D.; Magain, P.; Masek, M.; Cerny, J.; Ebr, J.; Prouza, M.; Kubanek,
P.; Jelinek, M.; Martin, J. L.; Gonzalez, J.; Carreno, A.; Piqueras,
J.; Pena Ciriza, F.; Garcia, F.; Henriquez, J. A.; Birtwhistle, P.;
Climent, T.; Williams, G. V.
2012MPEC....D...09K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Modelling the huge, Herschel-resolved debris ring around
HD 207129
Authors: Löhne, T.; Augereau, J. -C.; Ertel, S.; Marshall, J. P.;
Eiroa, C.; Mora, A.; Absil, O.; Stapelfeldt, K.; Thébault, P.; Bayo,
A.; Del Burgo, C.; Danchi, W.; Krivov, A. V.; Lebreton, J.; Letawe,
G.; Magain, P.; Maldonado, J.; Montesinos, B.; Pilbratt, G. L.; White,
G. J.; Wolf, S.
2012A&A...537A.110L Altcode:
Debris disks, which are inferred from the observed infrared excess to
be ensembles of dust, rocks, and probably planetesimals, are common
features of stellar systems. As the mechanisms of their formation
and evolution are linked to those of planetary bodies, they provide
valuable information. The few well-resolved debris disks are even
more valuable because they can serve as modelling benchmarks and
help resolve degeneracies in modelling aspects such as typical grain
sizes and distances. Here, we present an analysis of the HD 207129
debris disk, based on its well-covered spectral energy distribution
and Herschel/PACS images obtained in the framework of the DUNES
(DUst around NEarby Stars) programme. We use an empirical power-law
approach to the distribution of dust and we then model the production
and removal of dust by means of collisions, direct radiation pressure,
and drag forces. The resulting best-fit model contains a total of
nearly 10<SUP>-2</SUP> Earth masses in dust, with typical grain sizes
in the planetesimal belt ranging from 4 to 7 μm. We constrain the
dynamical excitation to be low, which results in very long collisional
lifetimes and a drag that notably fills the inner gap, especially at
70 μm. The radial distribution stretches from well within 100 AU in
an unusual, outward-rising slope towards a rather sharp outer edge
at about 170-190 AU. The inner edge is therefore smoother than that
reported for Fomalhaut, but the contribution from the extended halo
of barely bound grains is similarly small. Both slowly self-stirring
and planetary perturbations could potentially have formed and shaped
this disk. <P />Herschel is an ESA space observatory with science
instruments provided by European-led Principal Investigator consortia
and with important participation from NASA.
---------------------------------------------------------
Title: Observations and Orbits of Comets
Authors: Bacci, P.; Tesi, L.; Fagioli, G.; Jaeger, M.; Prosperi, E.;
Vollmann, W.; Foglia, S.; Galli, G.; Naves, R.; Campas, M.; Ligustri,
R.; Seki, T.; Shimomoto, S.; Sato, H.; Boattini, A.; Ahern, J. D.;
Beshore, E. C.; Garradd, G. J.; Gibbs, A. R.; Tricarico, P.; Grauer,
A. D.; Hill, R. E.; Kowalski, R. A.; Larson, S. M.; McNaught, R. H.;
Bezpalko, M.; Torres, D.; Kracke, R.; Spitz, G.; Kistler, J.; Stuart,
J.; Scruggs, S.; Ikari, Y.; Vidal, J. R.; Nicolas, J.; Lopesino, J.;
Martignoni, M.; Bryssinck, E.; Soulier, J. F.; Diepvens, A.; Grau
Horta, F.; Tremosa, L.; Brusa, M.; Sempio, L.; Ohshima, Y.; Hills,
K.; Takahashi, T.; Camilleri, P.; Primak, N.; Schultz, A.; Watters,
S.; Thiel, J.; Goggia, T.; Guido, E.; Howes, N.; Sostero, G.; Dymock,
R.; Ryan, E. L.; Shappee, B.; Thompson, D.; Woodward, C. E.; Elenin,
L.; Sherrod, P. C.; Ambrosioni Prosen, C.; Jehin, E.; Manfroid, J.;
Gillon, M.; Hutsemekers, D.; Magain, P.; Buczynski, D.; Limon, F.;
Gonzalez, J.; Garcia, F.; Henriquez, J. A.; Climent, T.; Williams,
G. V.
2012MPEC....A...52B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observations and Orbits of Comets
Authors: Kostov, A.; Vassileva, L.; Bacci, P.; Vergari, S.; Tesi,
L.; Fagioli, G.; Zakrajsek, J.; Casali, M.; Coffano, A.; Marinello,
W.; Micheli, M.; Pizzetti, G.; Antonini, P.; Haver, R.; Gorelli, R.;
Jaeger, M.; Prosperi, E.; Vollmann, W.; Buzzi, L.; Naves, R.; Campas,
M.; Hasubick, W.; Ligustri, R.; Nishiyama, K.; Hashimoto, N.; Kadota,
K.; Seki, T.; Shimomoto, S.; Sato, H.; Bill, H.; Arnold, L.; Baransky,
A.; Barinova, K.; Vorontseva, A.; Pettarin, E.; Grauer, A. D.; Hill,
R. E.; Ahern, J. D.; Beshore, E. C.; Boattini, A.; Garradd, G. J.;
Gibbs, A. R.; Tricarico, P.; Kowalski, R. A.; Larson, S. M.; McNaught,
R. H.; Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.; Festler, P.;
McVey, T.; Valdivia, A.; Gall, C.; Durig, D. T.; Ikari, Y.; Castellano,
J.; Dymock, R.; Vidal, J. R.; Karami, M.; Fathivavsari, H.; Vaduvescu,
O.; Bryssinck, E.; Linder, J.; Nicolas, J.; Martignoni, M.; Haeusler,
B.; Noel, T.; Diepvens, A.; Zilch, T.; Gerke, V.; Novichonok, A.;
Steffl, A.; Tremosa, L.; Caimmi, M.; Balanutsa, P.; Lipunov, V.;
Zimnukhov, D.; Gorbovskoy, E.; Shurpakov, S.; Hills, K.; Koishikawa,
M.; Takahashi, T.; Herald, D.; Camilleri, P.; Drummond, J.; Guido,
E.; Sostero, G.; Howes, N.; Sherrod, P. C.; Bell, C.; Ortiz, J. L.;
Morales, N.; de, I.; Ambrosioni Prosen, C.; Jehin, E.; Manfroid,
J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Buczynski, D.; Limon,
F.; Gonzalez, J.; Rinner, C.; Kugel, F.; Benkhaldoun, Z.; Muler, G.;
Ruiz, J. M.; Williams, G. V.
2012MPEC....B...23K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observations and Orbits of Comets
Authors: Vilagi, J.; Kornos, L.; Casali, M.; Coffano, A.; Marinello,
W.; Micheli, M.; Pizzetti, G.; Jaeger, M.; Prosperi, E.; Vollmann, W.;
Foglia, S.; Galli, G.; Buzzi, L.; Naves, R.; Campas, M.; Hasubick,
W.; Ligustri, R.; Kadota, K.; Seki, T.; Shimomoto, S.; Sato, H.;
Baransky, A.; Barinova, K.; Vorobjov, T.; Kowalski, R. A.; Gibbs,
A. R.; Ahern, J. D.; Beshore, E. C.; Boattini, A.; Garradd, G. J.;
Tricarico, P.; Grauer, A. D.; Hill, R. E.; Larson, S. M.; McNaught,
R. H.; Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.; Festler, P.;
McVey, T.; Valdivia, A.; Gall, C.; Durig, D. T.; Duddlesten, A. J.;
Cardamone, C. J.; Simpkins, H. R.; Lopez, J. O.; Clements, R. R.;
Gardner, M. M.; Jenkins, R. E.; Bailey, E. T.; Miedaner, K. E.; Stitts,
M. R.; Ikari, Y.; Castellano, J.; Vidal, J. R.; Dupouy, P.; James, N.;
Cozzi, E.; Kugel, F.; Franco, L.; Bryssinck, E.; Garrigos Sanchez,
A.; Nicolas, J.; Lopesino, J.; Borghini, W.; Bosch, J. M.; Olivera,
R. M.; Martignoni, M.; Haeusler, B.; Diepvens, A.; Hui, M. -T.; Gao,
X.; Tremosa, L.; Ohshima, Y.; Hills, K.; Koishikawa, M.; Takahashi,
T.; Herald, D.; Primak, N.; Schultz, A.; Watters, S.; Thiel, J.;
Goggia, T.; Guido, E.; Sostero, G.; Howes, N.; Elenin, L.; Sherrod,
P. C.; Ambrosioni Prosen, C.; Jehin, E.; Manfroid, J.; Gillon, M.;
Hutsemekers, D.; Magain, P.; Masek, M.; Cerny, J.; Ebr, J.; Prouza,
M.; Kubanek, P.; Jelinek, M.; Buczynski, D.; Carrillo, J.; Limon,
F.; Gonzalez, J.; Pena Ciriza, F.; Baez, J.; Garcia, F.; Muler, G.;
Ruiz, J. M.; Williams, G. V.
2012MPEC....B...78V Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Time delays for eleven gravitationally lensed quasars revisited
Authors: Eulaers, E.; Magain, P.
2011A&A...536A..44E Altcode: 2011arXiv1112.2609E
<BR /> Aims: We test the robustness of published time delays for
11 lensed quasars by using two techniques to measure time shifts in
their light curves. <BR /> Methods: We chose to use two fundamentally
different techniques to determine time delays in gravitationally lensed
quasars: a method based on fitting a numerical model and another one
derived from the minimum dispersion method introduced by Pelt and
collaborators. To analyse our sample in a homogeneous way and avoid
bias caused by the choice of the method used, we apply both methods to
11 different lensed systems for which delays have been published: JVAS
B0218+357, SBS 0909+523, RX J0911+0551, FBQS J0951+2635, HE 1104-1805,
PG 1115+080, JVAS B1422+231, SBS 1520+530, CLASS B1600+434, CLASS
B1608+656, and HE 2149-2745 <BR /> Results: Time delays for three
double lenses, JVAS B0218+357, HE 1104-1805, and CLASS B1600+434,
as well as the quadruply lensed quasar CLASS B1608+656 are confirmed
within the error bars. We correct the delay for SBS 1520+530. For PG
1115+080 and RX J0911+0551, the existence of a second solution on top
of the published delay is revealed. The time delays in four systems,
SBS 0909+523, FBQS J0951+2635, JVAS B1422+231, and HE 2149-2745 prove
to be less reliable than previously claimed. <BR /> Conclusions: If
we wish to derive an estimate of H<SUB>0</SUB> based on time delays
in gravitationally lensed quasars, we need to obtain more robust light
curves for most of these systems in order to achieve a higher accuracy
and robustness on the time delays.
---------------------------------------------------------
Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational
Lenses. IX. Time delays, lens dynamics and baryonic fraction in
HE 0435-1223
Authors: Courbin, F.; Chantry, V.; Revaz, Y.; Sluse, D.; Faure, C.;
Tewes, M.; Eulaers, E.; Koleva, M.; Asfandiyarov, I.; Dye, S.; Magain,
P.; van Winckel, H.; Coles, J.; Saha, P.; Ibrahimov, M.; Meylan, G.
2011A&A...536A..53C Altcode: 2010arXiv1009.1473C
We present accurate time delays for the quadruply imaged quasar HE
0435-1223. The delays were measured from 575 independent photometric
points obtained in the R-band between January 2004 and March 2010. With
seven years of data, we clearly show that quasar image A is affected
by strong microlensing variations and that the time delays are best
expressed relative to quasar image B. We measured Δt<SUB>BC</SUB> = 7.8
± 0.8 days, Δt<SUB>BD</SUB> = -6.5 ± 0.7 days and Δt<SUB>CD</SUB>
= -14.3 ± 0.8 days. We spacially deconvolved HST NICMOS2 F160W images
to derive accurate astrometry of the quasar images and to infer the
light profile of the lensing galaxy. We combined these images with
a stellar population fitting of a deep VLT spectrum of the lensing
galaxy to estimate the baryonic fraction, f<SUB>b</SUB>, in the Einstein
radius. We measured f<SUB>b</SUB> = 0.65<SUB>-0.10</SUB><SUP>+0.13</SUP>
if the lensing galaxy has a Salpeter IMF and f<SUB>b</SUB> =
0.45<SUB>-0.07</SUB><SUP>+0.04</SUP> if it has a Kroupa IMF. The
spectrum also allowed us to estimate the velocity dispersion of the
lensing galaxy, σ<SUB>ap</SUB> = 222 ± 34 km s<SUP>-1</SUP>. We used
f<SUB>b</SUB> and σ<SUB>ap</SUB> to constrain an analytical model
of the lensing galaxy composed of an Hernquist plus generalized NFW
profile. We solved the Jeans equations numerically for the model and
explored the parameter space under the additional requirement that the
model must predict the correct astrometry for the quasar images. Given
the current error bars on f<SUB>b</SUB> and σ<SUB>ap</SUB>, we
did not constrain H<SUB>0</SUB> yet with high accuracy, i.e., we
found a broad range of models with χ<SUP>2</SUP> < 1. However,
narrowing this range is possible, provided a better velocity dispersion
measurement becomes available. In addition, increasing the depth
of the current HST imaging data of HE 0435-1223 will allow us to
combine ourconstraints with lens reconstruction techniques that make
use of the full Einstein ring that is visible in this object. <P
/>Based on observations made with the 1.2 m Euler Swiss Telescope,
the 1.5 m telescope of Maidanak Observatory in Uzbekistan, and with
the 1.2 m Mercator Telescope, operated on the island of La Palma by
the Flemish Community, at the Spanish Observatorio del Roque de los
Muchachos of the Instituto de Astrofísica de Canarias. The NASA/ESA
Hubble Space Telescope data was obtained from the data archive at
the Space Telescope Science Institute, which is operated by AURA,
the Association of Universities for Research in Astronomy, Inc., under
NASA contract NAS-5-26555.Light curves are only available at the CDS
via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/536/A53">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/536/A53</A>
---------------------------------------------------------
Title: New Insights into the Quasar Type 1/Type 2 Dichotomy from
Correlations between Quasar Host Orientation and Polarization
Authors: Borguet, B.; Hutsemékers, D.; Letawe, G.; Letawe, Y.;
Magain, P.
2011ASPC..449..459B Altcode: 2008arXiv0809.4539B
We investigate correlations between the direction of the optical linear
polarization and the orientation of the host galaxy/extended emission
for type 1 and type 2 radio-loud and radio-quiet quasars. We have used
high resolution Hubble Space Telescope data and a deconvolution process
to obtain a good determination of the host galaxy/extended emission (EE)
position angle. With these new measurements and a compilation of data
from the literature, we find a significant correlation, different for
type 1 and type 2 objects, between the linear polarization position
angle and the orientation of the EE, suggesting scattering by an
extended UV/blue region in both types of objects. Our observations
support the extension of the Unification Model to the higher luminosity
AGNs like the quasars, assuming a two component scattering model.
---------------------------------------------------------
Title: Minor Planet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2011MPC..77008...8J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Comet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2011MPC..76684...9J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observations and Orbits of Comets
Authors: Sybiryakova, Y.; Kozyryev, Y.; Kulichenko, N.; Vovk, V.;
Shulga, O.; Cernis, K.; Zdanavicius, J.; Haver, R.; Buzzi, L.;
Naves, R.; Campas, M.; Hasubick, W.; Donati, S.; Meyer, M.; Scotti,
J. V.; Kadota, K.; Asami, A.; Abe, H.; Seki, T.; Shimomoto, S.; Sato,
H.; Wakuda, S.; Bill, H.; Arnold, L.; Micheli, M.; Elliott, G. T.;
Tholen, D. J.; Kashuba, S.; Kashuba, V.; Gorbanev, Y.; Podlesnyak,
S.; Stogneeva, I.; Baransky, A.; Barinova, K.; Markov, Y.; Vorontseva,
A.; Bressi, T. H.; Hergenrother, C. W.; Kowalski, R. A.; Hill, R. E.;
Boattini, A.; Ahern, J. D.; Beshore, E. C.; Garradd, G. J.; Gibbs,
A. R.; Tricarico, P.; Grauer, A. D.; Larson, S. M.; McNaught, R. H.;
Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.; Festler, P.; McVey,
T.; Valdivia, A.; Gall, C.; Moritz, N.; Elliott, R.; Durig, D. T.;
Roberts, C. A.; Smith, C. M.; Dziminski, H. T.; Ikari, Y.; Vidal,
J. R.; Dupouy, P.; Jaeger, M.; Prosperi, E.; Prosperi, S.; Vollmann,
W.; Shurpakov, S.; Bacci, P.; Antonacci, D.; Nevski, V.; Linder, J.;
Nicolas, J.; Lopesino, J.; Overhaus, C.; Haeusler, B.; Novichonok, A.;
Agletdinov, V.; Mezentsev, A.; Ignahin, V.; Bryssinck, E.; Veselkov,
S.; Bros, X.; Soulier, J. F.; Diepvens, A.; Zilch, T.; Gerke, V.;
Plaksa, S.; Chestnov, D.; Lindner, P.; Tudorica, A.; Badescu, T.;
Rosicarelli, M.; Capella, E.; Gaitan, J.; Zhao, H. B.; Yao, J. S.;
Zhaori, G. T.; Lu, H.; Wang, M.; Hong, R. Q.; Hu, L. F.; Xia, Y.;
Ohshima, Y.; Hills, K.; Takahashi, T.; Camilleri, P.; Primak, N.;
Schultz, A.; Watters, S.; Thiel, J.; Goggia, T.; Dymock, R.; Elenin,
L.; Sherrod, P. C.; Bell, C.; Ortiz, J. L.; Morales, N.; de, I.;
Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.;
Fraga, A.; Limon, F.; Gonzalez, J.; Baez, J.; Garcia, F.; Canales,
O.; Fletcher, J.; Williams, G. V.
2011MPEC....V...31S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Long term photometric monitoring of comet 103P/Hartley2 with
the new robotic TRAPPIST telescope
Authors: Jehin, E.; Manfroid, J.; Hutsemékers, D.; Gillon, M.;
Magain, P.
2011epsc.conf.1489J Altcode: 2011DPS....43.1489J; 2011epsc.conf.1479J
We report on a long term monitoring of comet 103P/Hartley2 with
six cometary narrow band filters using the TRAPPIST 0.60m telescope
installed recently at the ESO La Silla observatory in Chile. This
new robotic telescope is dedicated to exoplanet and solar system
research. The comet was observed with the cometary filters during 4
months, from Oct. 29 to Feb. 22. Since then the monitoring continues
but only through the BVRI filters and about two times per week. Those
observations allowed us to make a detailed light curve of the comet
after its perihelion passage and derive production rates of the 4
main species (OH, CN, C2, C3) as well as the dust production rate
(Afρ) over that period. The high sampling of our monitoring allowed
us to find a periodicity in the gaseous light curves and to deduce a
rotation period of 18.4h early November, slowing down to about 19h by
the end of December.
---------------------------------------------------------
Title: VizieR Online Data Catalog: R-band light curves of HE 0435-1223
(Courbin+, 2011)
Authors: Courbin, F.; Chantry, V.; Revaz, Y.; Sluse, D.; Faure, C.;
Tewes, M.; Eulaers, E.; Koleva, M.; Asfandiyarov, I.; Dye, S.; Magain,
P.; van Winckel, H.; Coles, J.; Saha, P.; Ibrahimov, M.; Meylan, G.
2011yCat..35360053C Altcode: 2011yCat..35369053C
Photometry of HE 0435-1223, as in Fig. 3 of the paper. The first column
gives the Julian date and corresponds to HJD days. Columns 2-9 give
the photometric measurements of the quasar components A, B, C and
D respectively, with the corresponding error bars. The last column
provides the name of the telescope used for each measurement. <P />(1
data file).
---------------------------------------------------------
Title: Observations and Orbits of Comets
Authors: Sanner, J.; Angelow, S.; Chaumont, F.; Heimann, L.; Lawida,
M.; Pollitt, A.; Proels, J.; Ronken, K.; Saenger, S.; Honkova, M.;
Tichy, M.; Ticha, J.; Kocer, M.; Bacci, P.; Tesi, L.; Fagioli, G.;
Tombelli, M.; Foglia, S.; Interrante, G.; Bartolini, S.; Casali,
M.; Coffano, A.; Marinello, W.; Micheli, M.; Pizzetti, G.; Jaeger,
M.; Prosperi, E.; Vollmann, W.; Buzzi, L.; Naves, R.; Campas, M.;
Donati, S.; Scotti, J. V.; Kadota, K.; Abe, H.; Seki, T.; Shimomoto,
S.; Sato, H.; Wakuda, S.; Jung, M.; Bill, H.; Kashuba, S.; Kashuba,
V.; Gorbanev, Y.; Podlesnyak, S.; Stogneeva, I.; Bressi, T. H.;
Gibbs, A. R.; Kowalski, R. A.; Hill, R. E.; Ahern, J. D.; Beshore,
E. C.; Boattini, A.; Garradd, G. J.; Tricarico, P.; Grauer, A. D.;
Larson, S. M.; McNaught, R. H.; Blythe, M.; Spitz, G.; Brungard, R.;
Paige, J.; Festler, P.; McVey, T.; Valdivia, A.; Gall, C.; Moritz,
N.; Elliott, R.; Castellano, J.; Vidal, J. R.; Dupouy, P.; Manzini,
F.; Behrend, R.; Bernasconi, L.; Shurpakov, S.; Thinius, B.; Nevski,
V.; Linder, J.; Nicolas, J.; Pivato, D.; Lopesino, J.; Overhaus, C.;
Bosch, J. M.; Olivera, R. M.; Martignoni, M.; Haeusler, B.; Noel,
T.; Bryssinck, E.; Sachot, G.; Soulier, J. F.; Diepvens, A.; Gerke,
V.; Novichonok, A.; Plyachshenko, Y.; Grau Horta, F.; Magrin, E.;
Gonano, V.; Andrea, M.; Zhao, H. B.; Yao, J. S.; Zhaori, G. T.; Lu,
H.; Wang, M.; Hong, R. Q.; Hu, L. F.; Xia, Y.; Sugiyama, Y.; Hills,
K.; Takahashi, T.; Herald, D.; Guido, E.; Howes, N.; Sostero, G.;
Lister, T.; Camilleri, P.; Drummond, J.; Primak, N.; Schultz, A.;
Watters, S.; Thiel, J.; Goggia, T.; Elenin, L.; Molotov, I.; Haugh,
T.; Bell, C.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.; Losse, F.; Limon, F.; Gonzalez, J.; Garcia, F.; Canales,
O.; Fletcher, J.; Ruiz, J.; Curto Amigo, J.; Williams, G. V.
2011MPEC....U...42S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Minor Planet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2011MPC..76020...7J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: WASP-50 b: a hot Jupiter transiting a moderately active
solar-type star
Authors: Gillon, M.; Doyle, A. P.; Lendl, M.; Maxted, P. F. L.;
Triaud, A. H. M. J.; Anderson, D. R.; Barros, S. C. C.; Bento, J.;
Collier-Cameron, A.; Enoch, B.; Faedi, F.; Hellier, C.; Jehin, E.;
Magain, P.; Montalbán, J.; Pepe, F.; Pollacco, D.; Queloz, D.;
Smalley, B.; Segransan, D.; Smith, A. M. S.; Southworth, J.; Udry,
S.; West, R. G.; Wheatley, P. J.
2011A&A...533A..88G Altcode: 2011arXiv1108.2641G
We report the discovery by the WASP transit survey of a giant planet
in a close orbit (0.0295 ± 0.0009 AU) around a moderately bright
(V = 11.6, K = 10) G9 dwarf (0.89 ± 0.08 M<SUB>⊙</SUB>, 0.84 ±
0.03 R<SUB>⊙</SUB>) in the Southern constellation Eridanus. Thanks
to high-precision follow-up photometry and spectroscopy obtained by
the telescopes TRAPPIST and Euler, the mass and size of this planet,
WASP-50 b, are well constrained to 1.47 ± 0.09 M<SUB>Jup</SUB>
and 1.15 ± 0.05 R<SUB>Jup</SUB>, respectively. The transit
ephemeris is 2 455 558.6120 (±0.0002) + N × 1.955096 (±0.000005)
HJD<SUB>UTC</SUB>. The size of the planet is consistent with basic
models of irradiated giant planets. The chromospheric activity (log
R'<SUB>HK = -4.67</SUB>) and rotational period (P<SUB>rot</SUB>
= 16.3 ± 0.5 days) of the host star suggest an age of 0.8 ± 0.4
Gy that is discrepant with a stellar-evolution estimate based on
the measured stellar parameters (ρ<SUB>∗</SUB> = 1.48 ± 0.10
ρ<SUB>⊙</SUB>, T<SUB>eff</SUB> = 5400 ± 100 K, [Fe/H] = -0.12
± 0.08) which favors an age of 7 ± 3.5 Gy. This discrepancy could
be explained by the tidal and magnetic influence of the planet on
the star, in good agreement with the observations that stars hosting
hot Jupiters tend to show faster rotation and magnetic activity. We
measure a stellar inclination of 84<SUB>-31<SUP>+6</SUP></SUB> deg,
disfavoring a high stellar obliquity. Thanks to its large irradiation
and the relatively small size of its host star, WASP-50 b is a
good target for occultation spectrophotometry, making it able to
constrain the relationship between hot Jupiters' atmospheric thermal
profiles and the chromospheric activity of their host stars. <P />The
photometric time-series used in this work are only available at the
CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/533/A88">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/533/A88</A>
---------------------------------------------------------
Title: TRAPPIST: TRAnsiting Planets and PlanetesImals Small Telescope
Authors: Jehin, E.; Gillon, M.; Queloz, D.; Magain, P.; Manfroid,
J.; Chantry, V.; Lendl, M.; Hutsemékers, D.; Udry, S.
2011Msngr.145....2J Altcode:
TRAPPIST is a 60-cm robotic telescope that was installed in April 2010
at the ESO La Silla Observatory. The project is led by the Astrophysics
and Image Processing group (AIP) at the Department of Astrophysics,
Geophysics and Oceanography (AGO) of the University of Liège, in
close collaboration with the Geneva Observatory, and has been funded by
the Belgian Fund for Scientific Research (F.R.S.-FNRS) and the Swiss
National Science Foundation (SNF). It is devoted to the detection and
characterisation of exoplanets and to the study of comets and other
small bodies in the Solar System. We describe here the goals of the
project and the hardware and present some results obtained during the
first six months of operation.
---------------------------------------------------------
Title: Observations and Orbits of Comets
Authors: Tesi, L.; Bacci, P.; Fagioli, G.; Tombelli, M.; Foglia, S.;
Galli, F.; Bartolini, S.; Cernis, K.; Zdanavicius, J.; Jaeger, M.;
Prosperi, E.; Vollmann, W.; Galli, G.; Buzzi, L.; Naves, R.; Campas,
M.; Kadota, K.; Abe, H.; Baransky, A.; Aleksakhina, E.; Ikari, Y.;
Vidal, J. R.; Kocher, P.; Rinner, C.; Kugel, F.; Reszelski, M.; Nevski,
V.; Linder, J.; Nicolas, J.; Pivato, D.; Haeusler, B.; Bryssinck,
E.; Plaksa, S.; Sachot, G.; Soulier, J. F.; Diepvens, A.; Lindner,
P.; Dangl, G.; Hills, K.; Herald, D.; McNaught, R. H.; Ahern, J. D.;
Beshore, E. C.; Boattini, A.; Garradd, G. J.; Gibbs, A. R.; Grauer,
A. D.; Hill, R. E.; Kowalski, R. A.; Larson, S. M.; Camilleri, P.;
McCormick, J.; Drummond, J.; Primak, N.; Schultz, A.; Watters, S.;
Thiel, J.; Goggia, T.; Boaz, R. Z.; Howes, N.; Blyth, H.; Sostero,
G.; Guido, E.; Sato, H.; Elenin, L.; Holmes, R.; Vorobjov, T.; Haugh,
T.; Bell, C.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.; Sparrenberger, M.; Ruiz, J. M.; Baez, J.; Lozano, I.;
Cardenete, S.; Chinchilla, J.; Garri, M.; Limon, F.; Gonzalez, J.;
Garcia, F.; Muler, G.; Vazquez Lopez, G.; Henriquez, J. A.; Canales,
O.; Benavides, R.; Temprano, J.; Fletcher, J.; Williams, G. V.
2011MPEC....P...23T Altcode:
No abstract at ADS
---------------------------------------------------------
Title: VizieR Online Data Catalog: WASP-50b photometry and radial
velocities (Gillon+, 2011)
Authors: Gillon, M.; Doyle, A. P.; Lendl, M.; Maxted, P. F. L.;
Triaud, A. H. M. J.; Anderson, D. R.; Barros, S. C. C.; Bento,
J.; Collier-Cameron, A.; Enoch, B.; Faedi, F.; Hellier, C.; Jehin,
E.; Magain, P.; Montalban, J.; Pepe, F.; Pollacco, D.; Queloz, D.;
Smalley, B.; Segransan, D.; Smith, A. M. S.; Southworth, J.; Udry,
S.; West, R. G.; Wheatley, P. J.
2011yCat..35330088G Altcode: 2011yCat..35339088G
Files wasp.dat, trappist.dat and euler.dat contain the photometric
time-series presented in the paper and obtained by the WASP transit
survey, and by the TRAPPIST and Euler telescopes. <P />(4 data files).
---------------------------------------------------------
Title: Minor Planet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2011MPC..75700...7J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Comet 45P/HONDA-MRKOS-PAJDUSAKOVA
Authors: McNaught, R. H.; Jehin, E.; Manfroid, J.; Gillon, M.;
Hutsemekers, D.; Magain, P.; Williams, G. V.
2011MPEC....P...11M Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Comet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2011MPC..75563...4J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Minor Planet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2011MPC..75510..12J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observations and Orbits of Comets
Authors: Tesi, L.; Bacci, P.; Fagioli, G.; Bacci, R.; Casali, M.;
Coffano, A.; Marinello, W.; Micheli, M.; Pizzetti, G.; Cernis, K.;
Zdanavicius, J.; Maskoliunas, M.; Haver, R.; Foglia, S.; Galli, G.;
Buzzi, L.; Naves, R.; Campas, M.; Hasubick, W.; Donati, S.; McAndrew,
S. G.; Sanchez C., A.; Donato, L.; Gonano, V.; Travagini, M.; Bill, H.;
Baransky, A.; Buriev, A.; Ponomarenko, V.; Scotti, J. V.; Kowalski,
R. A.; Ahern, J. D.; Beshore, E. C.; Boattini, A.; Garradd, G. J.;
Gibbs, A. R.; Tricarico, P.; Grauer, A. D.; Hill, R. E.; Larson,
S. M.; McNaught, R. H.; Blythe, M.; Spitz, G.; Brungard, R.; Paige,
J.; Festler, P.; McVey, T.; Valdivia, A.; Brewington, H.; Dembicky,
J.; Harvanek, M.; Ketzeback, B.; Long, D.; Pan, K.; Malanushenko, O.;
McMillan, R.; Snedden, S.; Watters, S.; Sarneczky, K.; Durig, D. T.;
Uriostegui, J. R.; Danusantoso, J. F.; Kharel, S.; Duenas, D. E.;
Rice, A. C.; Vasquez, J. A.; Murphree, C. L.; Koury, E. S.; Castellano,
J.; Ferrando, R.; Vidal, J. R.; Baldris, F.; Kocher, P.; Jaeger, M.;
Prosperi, E.; Vollmann, W.; Rinner, C.; Kugel, F.; Nicolas, J.; Bel,
J.; Borghini, W.; Bryssinck, E.; Sachot, G.; Soulier, J. F.; Diepvens,
A.; Dangl, G.; Hills, K.; Takahashi, T.; Novichonok, A.; Baroni, S.;
Concari, P.; Tombelli, M.; Chestnov, D.; Sato, H.; Herald, D.; Lister,
T.; Guido, E.; Howes, N.; Sostero, G.; McCormick, J.; Primak, N.;
Schultz, A.; Thiel, J.; Goggia, T.; Glinos, T.; Plaksa, S.; Elenin,
L.; Hall-Angel Peaks Observatory, J.; Hall, J.; Holmes, R.; Vorobjov,
T.; Linder, T.; Mills, M.; Hug, G.; Sherrod, P. C.; Bell, C.; Jehin,
E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Limon,
F.; Gonzalez, J.; Pena Ciriza, F.; Del Maes, A.; Hernandez, J. F.;
Garcia, F.; Fletcher, J.; Climent, T.; Williams, G. V.
2011MPEC....N...13T Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Comet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2011MPC..75359..19J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observations and Orbits of Comets
Authors: Naves, R.; Campas, M.; Seki, T.; Shimomoto, S.; Sato, H.;
Donato, L.; Gonano, V.; Travagini, M.; Baransky, A.; Buriev, A.;
Ponomarenko, V.; Beshore, E.; Ahern, J. D.; Boattini, A.; Garradd,
G. J.; Gibbs, A. R.; Tricarico, P.; Grauer, A. D.; Hill, R. E.;
Kowalski, R. A.; Larson, S. M.; McNaught, R. H.; Blythe, M.; Spitz,
G.; Brungard, R.; Paige, J.; Festler, P.; McVey, T.; Valdivia, A.;
Schwartz, M.; Holvorcem, P. R.; Jaeger, M.; Prosperi, E.; Vollmann,
W.; Rinner, C.; Kugel, F.; Camarasa, J.; Bryssinck, E.; Sachot,
G.; Diepvens, A.; Hills, K.; Takahashi, T.; Baroni, S.; Buzzi, L.;
Concari, P.; Foglia, S.; Galli, G.; Tombelli, M.; Camilleri, P.;
Primak, N.; Schultz, A.; Watters, S.; Thiel, J.; Goggia, T.; Glinos,
T.; Guido, E.; Sostero, G.; Bell, C.; Jehin, E.; Manfroid, J.; Gillon,
M.; Hutsemekers, D.; Magain, P.; Williams, G. V.
2011MPEC....M...11N Altcode:
No abstract at ADS
---------------------------------------------------------
Title: EPOXI: Comet 103P/Hartley 2 Observations from a Worldwide
Campaign
Authors: Meech, K. J.; A'Hearn, M. F.; Adams, J. A.; Bacci, P.; Bai,
J.; Barrera, L.; Battelino, M.; Bauer, J. M.; Becklin, E.; Bhatt,
B.; Biver, N.; Bockelée-Morvan, D.; Bodewits, D.; Böhnhardt, H.;
Boissier, J.; Bonev, B. P.; Borghini, W.; Brucato, J. R.; Bryssinck,
E.; Buie, M. W.; Canovas, H.; Castellano, D.; Charnley, S. B.;
Chen, W. P.; Chiang, P.; Choi, Y. -J.; Christian, D. J.; Chuang,
Y. -L.; Cochran, A. L.; Colom, P.; Combi, M. R.; Coulson, I. M.;
Crovisier, J.; Dello Russo, N.; Dennerl, K.; DeWahl, K.; DiSanti,
M. A.; Facchini, M.; Farnham, T. L.; Fernández, Y.; Florén,
H. G.; Frisk, U.; Fujiyoshi, T.; Furusho, R.; Fuse, T.; Galli, G.;
García-Hernández, D. A.; Gersch, A.; Getu, Z.; Gibb, E. L.; Gillon,
M.; Guido, E.; Guillermo, R. A.; Hadamcik, E.; Hainaut, O.; Hammel,
H. B.; Harker, D. E.; Harmon, J. K.; Harris, W. M.; Hartogh, P.;
Hashimoto, M.; Häusler, B.; Herter, T.; Hjalmarson, A.; Holland,
S. T.; Honda, M.; Hosseini, S.; Howell, E. S.; Howes, N.; Hsieh,
H. H.; Hsiao, H. -Y.; Hutsemékers, D.; Immler, S. M.; Jackson, W. M.;
Jeffers, S. V.; Jehin, E.; Jones, T. J.; de Juan Ovelar, M.; Kaluna,
H. M.; Karlsson, T.; Kawakita, H.; Keane, J. V.; Keller, L. D.;
Kelley, M. S.; Kinoshita, D.; Kiselev, N. N.; Kleyna, J.; Knight,
M. M.; Kobayashi, H.; Kobulnicky, H. A.; Kolokolova, L.; Kreiny, M.;
Kuan, Y. -J.; Küppers, M.; Lacruz, J. M.; Landsman, W. B.; Lara,
L. M.; Lecacheux, A.; Levasseur-Regourd, A. C.; Li, B.; Licandro,
J.; Ligustri, R.; Lin, Z. -Y.; Lippi, M.; Lis, D. C.; Lisse, C. M.;
Lovell, A. J.; Lowry, S. C.; Lu, H.; Lundin, S.; Magee-Sauer, K.;
Magain, P.; Manfroid, J.; Mazzotta Epifani, E.; McKay, A.; Melita,
M. D.; Mikuz, H.; Milam, S. N.; Milani, G.; Min, M.; Moreno, R.;
Mueller, B. E. A.; Mumma, M. J.; Nicolini, M.; Nolan, M. C.; Nordh,
H. L.; Nowajewski, P. B.; Odin Team; Ootsubo, T.; Paganini, L.;
Perrella, C.; Pittichová, J.; Prosperi, E.; Radeva, Y. L.; Reach,
W. T.; Remijan, A. J.; Rengel, M.; Riesen, T. E.; Rodenhuis, M.;
Rodríguez, D. P.; Russell, R. W.; Sahu, D. K.; Samarasinha, N. H.;
Sánchez Caso, A.; Sandqvist, A.; Sarid, G.; Sato, M.; Schleicher,
D. G.; Schwieterman, E. W.; Sen, A. K.; Shenoy, D.; Shi, J. -C.;
Shinnaka, Y.; Skvarc, J.; Snodgrass, C.; Sitko, M. L.; Sonnett, S.;
Sosseini, S.; Sostero, G.; Sugita, S.; Swinyard, B. M.; Szutowicz,
S.; Takato, N.; Tanga, P.; Taylor, P. A.; Tozzi, G. -P.; Trabatti,
R.; Trigo-Rodríguez, J. M.; Tubiana, C.; de Val-Borro, M.; Vacca,
W.; Vandenbussche, B.; Vaubaillion, J.; Velichko, F. P.; Velichko,
S. F.; Vervack, R. J., Jr.; Vidal-Nunez, M. J.; Villanueva, G. L.;
Vinante, C.; Vincent, J. -B.; Wang, M.; Wasserman, L. H.; Watanabe,
J.; Weaver, H. A.; Weissman, P. R.; Wolk, S.; Wooden, D. H.; Woodward,
C. E.; Yamaguchi, M.; Yamashita, T.; Yanamandra-Fischer, P. A.; Yang,
B.; Yao, J. -S.; Yeomans, D. K.; Zenn, T.; Zhao, H.; Ziffer, J. E.
2011ApJ...734L...1M Altcode: 2011arXiv1106.0367K
Earth- and space-based observations provide synergistic information
for space mission encounters by providing data over longer timescales,
at different wavelengths and using techniques that are impossible with
an in situ flyby. We report here such observations in support of the
EPOXI spacecraft flyby of comet 103P/Hartley 2. The nucleus is small and
dark, and exhibited a very rapidly changing rotation period. Prior to
the onset of activity, the period was ~16.4 hr. Starting in 2010 August
the period changed from 16.6 hr to near 19 hr in December. With respect
to dust composition, most volatiles and carbon and nitrogen isotope
ratios, the comet is similar to other Jupiter-family comets. What
is unusual is the dominance of CO<SUB>2</SUB>-driven activity near
perihelion, which likely persists out to aphelion. Near perihelion the
comet nucleus was surrounded by a large halo of water-ice grains that
contributed significantly to the total water production.
---------------------------------------------------------
Title: Minor Planet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2011MPC..75288...5J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observations and Orbits of Comets
Authors: Eglitis, I.; Cernis, K.; Tesi, L.; Bacci, P.; Fagioli,
G.; Caronia, A.; Buzzi, L.; Urakawa, S.; Hashimoto, N.; Asami, A.;
Nishiyama, K.; Okumura, S.; Sakamoto, T.; Kadota, K.; Abe, H.; Seki,
T.; Shimomoto, S.; Sato, H.; Endate, K.; Sarneczky, K.; Donato,
L.; Gonano, V.; Travagini, M.; Bill, H.; Kashuba, S.; Kashuba, V.;
Gorbanev, Y.; Podlesnyak, S.; Stogneeva, I.; Baransky, A.; Buriev,
A.; Ponomarenko, V.; Zhdanov, A.; Butygina, O.; Weissman, P. R.;
Brozovic, M.; Owen, W. M., Jr.; Bressi, T. H.; Hergenrother, C. W.;
Grauer, A. D.; Gibbs, A. R.; Kowalski, R. A.; Beshore, E.; Ahern,
J. D.; Boattini, A.; Garradd, G. J.; Tricarico, P.; Hill, R. E.;
Larson, S. M.; McNaught, R. H.; Blythe, M.; Spitz, G.; Brungard,
R.; Paige, J.; Festler, P.; McVey, T.; Valdivia, A.; Mackintosh,
R.; Konishi, M.; Salvo, R.; Bruzzone, S.; Roland, S.; Tancredi,
G.; Martinez, M.; Abe, S.; Guo, J. K.; Chen, W. P.; Schwartz, M.;
Holvorcem, P. R.; Castellano, J.; Vidal, J. R.; Dupouy, P.; Baldris,
F.; Jaeger, M.; Prosperi, E.; Prosperi, S.; Vollmann, W.; Rinner, C.;
Kugel, F.; Bryssinck, E.; Soulier, J. F.; Diepvens, A.; Zilch, T.;
Hills, K.; Takahashi, T.; Baroni, S.; Concari, P.; Foglia, S.; Galli,
G.; Tombelli, M.; Camilleri, P.; Linder, J.; Herald, D.; Miles, R.;
Primak, N.; Schultz, A.; Watters, S.; Thiel, J.; Goggia, T.; Micheli,
M.; Dymock, R.; Masek, M.; Chestnov, D.; Novichonok, A.; Plaksa, S.;
Elenin, L.; Holmes, R.; Vorobjov, T.; Sherrod, P. C.; Bell, C.; Colazo,
C.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.;
Gonzalez, J.; Hernandez, J. F.; Garcia, F.; Lacruz, J.; Williams, G. V.
2011MPEC....L...51E Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Comet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2011MPC..75109..50J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Comet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2011MPC..74775..38J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observations and Orbits of Comets
Authors: Tesi, L.; Bacci, P.; Fagioli, G.; Vivarelli, M.; Greco, L.;
Casali, M.; Coffano, A.; Marinello, W.; Micheli, M.; Pizzetti, G.;
Apitzsch, R.; Naves, R.; Campas, M.; Hasubick, W.; Seki, T.; Shimomoto,
S.; Sato, H.; Christie, G. W.; Natusch, T.; Donato, L.; Gonano, V.;
Travagini, M.; Bill, H.; Baransky, A.; Bambery, R.; Helin, E.; Pravdo,
S.; Hicks, M.; Lawrence, K.; Kervin, P.; Matson, R.; Grauer, A. D.;
Gibbs, A. R.; Ahern, J. D.; Beshore, E. C.; Boattini, A.; Garradd,
G. J.; Tricarico, P.; Hill, R. E.; Kowalski, R. A.; Larson, S. M.;
McNaught, R. H.; Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.;
Festler, P.; McVey, T.; Valdivia, A.; Castellano, J.; Ferrando,
R.; Vidal, J. R.; Dupouy, P.; Baldris, F.; Muller, J. J.; Cozzi,
E.; Jaeger, M.; Prosperi, E.; Vollmann, W.; Rinner, C.; Kugel, F.;
Franco, L.; Camarasa, J.; Nicolas, J.; Bosch, J. M.; Soulier, J. F.;
Diepvens, A.; Ohshima, Y.; Takahashi, T.; Camilleri, P.; Sostero,
G.; Guido, E.; Bryssinck, E.; Chestnov, D.; Novichonok, A.; Plaksa,
S.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain,
P.; Buczynski, D.; Fraga, A.; Losse, F.; Pena Ciriza, F.; Del Maes,
A.; Muler, G.; Ruiz, J. M.; Williams, G. V.
2011MPEC....J...52T Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Minor Planet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain,
P.; Levesque, M.; Christiaens, V.
2011MPC..75004..11J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observations and Orbits of Comets
Authors: Tesi, L.; Bacci, P.; Garozzo, M.; Mikuz, B.; Mikuz, H.;
Knoefel, A.; Lehmann, G.; Vilagi, J.; Kornos, L.; Haver, R.; Jaeger,
M.; Prosperi, E.; Vollmann, W.; Buzzi, L.; Naves, R.; Campas, M.;
Hasubick, W.; Donati, S.; Ligustri, R.; Brunato, P.; Kadota, K.; Abe,
H.; Seki, T.; Shimomoto, S.; Sato, H.; Endate, K.; Sanchez, A.; Kuli,
Z.; Sarneczky, K.; Christie, G. W.; Natusch, T.; Bill, H.; Quadri, U.;
Strabla, L.; Girelli, R.; Kashuba, S.; Gorbanev, Y.; Podlesnyak, S.;
Stogneeva, I.; Baransky, A.; Zhdanov, A.; Vorontseva, A.; Markov, Y.;
Bressi, T. H.; Scotti, J. V.; Grauer, A. D.; Boattini, A.; Tricarico,
P.; Kowalski, R. A.; Hill, R. E.; Ahern, J. D.; Beshore, E. C.;
Garradd, G. J.; Gibbs, A. R.; Tric, P.; Larson, S. M.; McNaught,
R. H.; Tricario, P.; Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.;
Festler, P.; McVey, T.; Valdivia, A.; Durig, D. T.; Caine, C. S.;
Green, J. P.; Best, H. L.; Hamilton, I. G.; Liu, H.; Skidmore, L. M.;
Stinson, J. W.; Cowan, W. M.; Ikari, Y.; Castellano, J.; Dymock, R.;
Vidal, J. R.; Dupouy, P.; Storey, D.; Mueller, J. J.; Cozzi, E.;
Rinner, C.; Kugel, F.; Franco, L.; Shurpakov, S.; Pietschnig, M.;
Aymami, J. M.; Nevski, V.; Linder, J.; Bel, J.; Overhaus, C.; Bosch,
J. M.; Haeusler, B.; Noel, T.; Bryssinck, E.; Sachot, G.; Soulier,
J. F.; Diepvens, A.; Zilch, T.; Gao, X.; Hui, M. -T.; Plyachshenko,
Y.; Curtis, I.; Hills, K.; Takahashi, T.; Camilleri, P.; Chestnov,
D.; Novichonok, A.; Plaksa, S.; Baroni, S.; Concari, P.; Foglia, S.;
Galli, G.; Tombelli, M.; Sostero, G.; Guido, E.; Kiely, W.; Herald,
D.; McCormick, J.; Primak, N.; Schultz, A.; Watters, S.; Thiel, J.;
Goggia, T.; Hergenrother, C. W.; Elenin, L.; Holmes, R.; Vorobjov, T.;
Haugh, T.; Sherrod, P. C.; Bell, C.; Tifner, F.; Jehin, E.; Manfroid,
J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Eugenio Tapia Ayuga, C.;
Losse, F.; Limon, F.; Gonzalez, J.; Martin, J. J.; Garcia, F.; Muler,
G.; Ruiz, J. M.; Canales, O.; Temprano, J.; Lacruz, J.; Fletcher,
J.; Williams, G. V.
2011MPEC....G...58T Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Minor Planet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain,
P.; Christiaens, V.
2011MPC..74632...9J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Comet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2011MPC..74333..40J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observations and Orbits of Comets
Authors: Tombelli, M.; Foglia, S.; Interrante, G.; Masotti, E.;
Castro, L.; Casali, M.; Marinello, W.; Micheli, M.; Pizzetti, G.;
Soffiantini, A.; Buzzi, L.; Almendros, I.; Naves, R.; Campas, M.;
Reina, E.; Ligustri, R.; Brunato, P.; Turchetti, R.; Benvenuti, M.;
Scotti, J. V.; Asami, A.; Hashimoto, N.; Nishiyama, K.; Okumura, S.;
Sakamoto, T.; Urakawa, S.; Abe, H.; Seki, T.; Shimomoto, S.; Sato, H.;
Endate, K.; McAndrew, S. G.; Donato, L.; Gonano, V.; Travagini, M.;
Kelemen, J.; Baransky, A.; Zhdanov, A.; Pasichnyk, P.; Ponomarenko,
V.; Vorontseva, A.; Markov, Y.; Barinova, K.; Tarasenko, Y.; Hill,
R. E.; Ahern, J. D.; Beshore, E. C.; Boattini, A.; Garradd, G. J.;
Gibbs, A. R.; Tricarico, P.; Grauer, A. D.; Kowalski, R. A.; Larson,
S. M.; McNaught, R. H.; Blythe, M.; Spitz, G.; Brungard, R.; Paige,
J.; Festler, P.; McVey, T.; Valdivia, A.; Mackintosh, R.; Konishi,
M.; Durig, D. T.; Green, J. P.; Maxey, S. H.; Patton, J. E.; Stevens,
D. S.; Singer, J. T.; Skidmore, L. M.; Morgan, W. R.; Vines, L. F.;
Castellano, J.; Ferrando, R.; Ferrando, M.; Vidal, J. R.; Dupouy,
P.; Mueller, J. J.; Jaeger, M.; Prosperi, E.; Prosperi, S.; Vollmann,
W.; Rinner, C.; Kugel, F.; Nevski, V.; Haeusler, B.; Bryssinck, E.;
Soulier, J. F.; Diepvens, A.; Shurpakov, S.; Hui, M. -T.; Sugiyama,
Y.; Camilleri, P.; Plaksa, S.; Primak, N.; Schultz, A.; Watters,
S.; Thiel, J.; Goggia, T.; Chestnov, D.; Novichonok, A.; Elenin,
L.; Molotov, I.; Sherrod, P. C.; Bell, C.; Jehin, E.; Manfroid,
J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Gonzalez, J.; Garcia,
R.; Pena Ciriza, F.; Del Maes, A.; Baez, J.; Garcia, F.; Muler, G.;
Ruiz, J. M.; Henriquez, J. A.; Canales, O.; Curto, J.; Temprano, J.;
Pascual, J. I.; Williams, G. V.
2011MPEC....G...90T Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Comet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2011MPC..73990..25J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Minor Planet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2011MPC..74232...7J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: TRAPPIST: a robotic telescope dedicated to the study of
planetary systems
Authors: Gillon, M.; Jehin, E.; Magain, P.; Chantry, V.; Hutsemékers,
D.; Manfroid, J.; Queloz, D.; Udry, S.
2011EPJWC..1106002G Altcode: 2011arXiv1101.5807G
We present here a new robotic telescope called TRAPPIST (TRAnsiting
Planets and PlanetesImals Small Telescope). Equipped with a high-quality
CCD camera mounted on a 0.6 meter light weight optical tube, TRAPPIST
has been installed in April 2010 at the ESO La Silla Observatory
(Chile), and is now beginning its scientific program. The science goal
of TRAPPIST is the study of planetary systems through two approaches:
the detection and study of exoplanets, and the study of comets. We
describe here the objectives of the project, the hardware, and we
present some of the first results obtained during the commissioning
phase.
---------------------------------------------------------
Title: Observations and Orbits of Comets
Authors: Gajdos, S.; Vilagi, J.; Apitzsch, R.; Buzzi, L.; Ligustri,
R.; Kadota, K.; Asami, A.; Seki, T.; Muraoka, K.; Shimomoto, S.;
Donato, L.; Gonano, V.; Jung, M.; Bill, H.; Kelemen, J.; Kashuba, S.;
Kashuba, V.; Gorbanev, Y.; Podlesnyak, S.; Stogneeva, I.; Baransky,
A.; Ponomarenko, V.; Simon, A.; Boattini, A.; Ahern, J. D.; Beshore,
E. C.; Garradd, G. J.; Gibbs, A. R.; Grauer, A. D.; Hill, R. E.;
Kowalski, R. A.; Larson, S. M.; McNaught, R. H.; Blythe, M.; Spitz,
G.; Brungard, R.; Paige, J.; Festler, P.; McVey, T.; Valdivia, A.;
Ikari, Y.; Castellano, J.; Kocher, P.; Rinner, C.; Kugel, F.; Bacci,
P.; Enzo, R.; Emilio, R.; Martignoni, M.; Bryssinck, E.; Soulier, J.;
Curtis, I.; Hills, K.; Takahashi, T.; Camilleri, P.; Sato, H.; Herald,
D.; Drummond, J.; Dymock, R.; Chestnov, D.; Novichonok, A.; Linder,
J.; Baroni, S.; Concari, P.; Foglia, S.; Galli, G.; Tombelli, M.;
Elenin, L.; Molotov, I.; Bell, C.; Jehin, E.; Manfroid, J.; Gillon,
M.; Hutsemekers, D.; Magain, P.; Carreno, A.; Piqueras, J.; Hernandez,
J. F.; Garcia, F.; Muler, G.; Ruiz, J. M.; Williams, G. V.
2011MPEC....D...36G Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Comet Observations [I40 La Silla--TRAPPIST]
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2011MPC..73618..49J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Comet P/2005 l1 (mcnaught)
Authors: Honkova, M.; Tichy, M.; Ticha, J.; Kocer, M.; Bilkina, B.;
Tesi, L.; Fagioli, G.; Bacci, P.; Mikuz, H.; Gajdos, S.; Vilagi, J.;
Casali, M.; Marinello, W.; Micheli, M.; Pizzetti, G.; Soffiantini, A.;
Galli, G.; Buzzi, L.; Almendros, I.; Naves, R.; Campas, M.; Hasubick,
W.; Scotti, J. V.; Asami, A.; Nishiyama, K.; Kadota, K.; Abe, H.;
Seki, T.; Shimomoto, S.; Sato, H.; Muraoka, K.; Wakuda, S.; Kuli, Z.;
Sarneczky, K.; Donato, L.; Gonano, V.; Muschallik, I.; Peters, J. P.;
Bill, H.; Elliott, G. T.; Tholen, D. J.; Pittichova, J.; Kleyna, J.;
Ishiguro, M.; Baransky, A.; Baransky, B.; Baranska, O.; Grauer, A. D.;
Kowalski, R. A.; Boattini, A.; Hill, R. E.; Ahern, J. D.; Beshore,
E. C.; Garradd, G. J.; Gibbs, A. R.; Larson, S. M.; McNaught, R. H.;
Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.; Festler, P.; McVey, T.;
Valdivia, A.; Durig, D. T.; Murphree, V. J.; Wetherbee, R. M.; Liu,
H.; Caine, C. S.; Hamilton, I. G.; Ikari, Y.; Le Corre, L.; Reddy,
V.; Dyvig, R.; Castellano, J.; Vidal, J. R.; Dupouy, P.; Baldris,
F.; Cortes, E.; Jaeger, M.; Prosperi, E.; Prosperi, S.; Vollmann,
W.; Rinner, C.; Kugel, F.; Trigo-Rodriguez, J. M.; Camarasa, J.;
Bel, J.; Lopesino, J.; Borghini, W.; Bosch, J. M.; Martignoni, M.;
Haeusler, B.; Noel, T.; Bryssinck, E.; Bros, X.; Sachot, G.; Soulier,
J.; Rhemann, G.; Chestnov, D.; Matkin, A.; de Groote, B.; Diepvens,
A.; Xu, Z.; Gao, X.; Ohshima, Y.; Sugiyama, Y.; Hills, K.; Takahashi,
T.; Shurpakov, S.; Linder, J.; Sostero, G.; Guido, E.; Novichonok,
A.; McCusker, C.; McInteggart, H.; Adams, J.; Camilleri, P.; Dymock,
R.; Glinos, T.; Ryan, W. H.; Ryan, E. V.; Ligustri, R.; Plaksa, S.;
Baroni, S.; Concari, P.; Foglia, S.; Tombelli, M.; Karge, S.; Elenin,
L.; Molotov, I.; Sherrod, P. C.; Bell, C.; Renzi, M.; Jehin, E.;
Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Limon, F.;
Gonzalez, J.; Carreno, A.; Piqueras, J.; Hernandez, J. F.; Martin,
J. J.; Baez, J.; Garcia, F.; Ruiz, J. M.; Muler, G.; Benavides, R.;
Curto, J.; Temprano, J.; Pascual, J. I.; Climent, T.; Williams, G. V.
2011MPEC....D...06H Altcode:
No abstract at ADS
---------------------------------------------------------
Title: (596) Scheila
Authors: Jehin, E.; Manfroid, J.; Hutsemekers, D.; Gillon, M.;
Magain, P.
2011CBET.2632....2J Altcode:
E. Jehin, J. Manfroid, D. Hutsemekers, M. Gillon, and P. Magain,
Fonds National de la Recherche Scientifique, Liege University, report
on broad- and narrow-band imaging of the (596) Scheila outburst
(CBET 2583) with the TRAPPIST 0.60-m telescope at La Silla, and
on optical spectroscopy with the European Southern Observatory's
Very Large Telescope (VLT) at Paranal. R-band imaging from 2010
Dec. 12.3 to 21.3 UT revealed two arc-like coma features expanding
at a regular pace. The first such feature was 1' long on 2010
Dec. 12, oriented to the northeast and bending to p.a. 280 deg
(the anti-solar direction). The second feature was shorter, 30"
on Dec. 12, oriented to the south and bending to p.a. 230 deg. Both
features were getting larger and fainter with time (4' and 2' long,
respectively, on Dec. 21.3). A narrow 45"-long tail, opposite the sun
(p.a. 280 deg), was also observed in good seeing. R-band images taken
on 2011 Jan. 4.3 and 5.3 after the full moon allowed Jehin et al. to
again observe these features, seen as 7' and 4' long, respectively --
and much fainter. This discards any sustained activity of the minor
planet. Narrow-band images obtained on 2010 Dec. 12.3 with cometary
filters do not show any contribution from gases. A 20-min optical
spectrum was obtained with FORS2 at the VLT on Dec. 13.3; it does not
show any extended cometary gaseous emissions, but only a spatially
extended continuum due to dust-scattered sunlight. Short B, V, R,
and I exposures performed nearly every two nights from 2010 Dec. 12.3
to 2011 Jan. 5.3 give a magnitude for the nuclear condensation of V =
14.2 +/- 0.1 over the whole period, in agreement with the "APmag" value
reported in the Jet Propulsion Laboratory ephemeris. No flux variation
of the nuclear condensation was observed. Those preliminary results are
in favor of a collisional scenario to explain the outburst of (596)
Scheila, rather than a cometary driven activity. This case might be
similar to the outburst of comet P/2010 A2, which may have resulted
from an impact of a minor planet (Snodgrass 2010, Nature 467, 814).
---------------------------------------------------------
Title: Comet 103P/Hartley
Authors: Jehin, E.; Manfroid, J.; Hutsemekers, D.; Gillon, M.;
Magain, P.
2010CBET.2589....1J Altcode:
E. Jehin, J. Manfroid, D. Hutsemekers, M. Gillon, and P. Magain, Liege
University, report narrowband imaging of comet 103P using the TRAPPIST
0.60m telescope at the European Southern Observatory, La Silla. Three to
four hours of observation were secured on 26 clear nights from Oct. 29
to Dec. 7, using six different cometary filters (Farnham et al. 2000,
Icarus 147, 180). The flux of five gaseous species (CN, OH, H_2O+,
C_2, C_3) and the dust continuum (via the C/1995 O1 green continuum
filter, GC) was measured in a 26" aperture. Periodic variations of
the gas species are observed, superimposed on the long-term trend,
with CN showing the strongest variations (0.4-mag amplitude). The dust
light curve is nearly flat. No gas or dust outburst has been detected
during the above period of observation, although CN and OH show a
slow flux increase with respect to other species during several days
in early November. A period search with the first two weeks of data
gave a smooth phase diagram for a period of 18.4 +/- 0.3 hours. These
observations are in good agreement with the period reported from Arecibo
radar observations of the nucleus (18.1 +/- 0.3 hours on Oct. 24-27;
IAUC 9179). Including two more weeks of data, it became clear that
the period was increasing. A change from about 18.2 to 19 hours was
derived during the above observing window that might be related to a
change of the rotation period of comet 103P of about 2 hours in 100
days. Such a rapid slowing down is in agreement with rotation values
reported before perihelion (16.6 +/- 0.5 hr on Aug. 13-17; IAUC 9163).
---------------------------------------------------------
Title: Occultation by (136199) Eris
Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.;
Magain, P.
2010IAUC.9184....2J Altcode: 2010IAUC.9184B...2J
E. Jehin, J. Manfroid, M. Gillon, D. Hutsemekers, and P. Magain report
that they observed an occultation of a star of magnitude I about 15.2
by the dwarf planet Eris (then at V about 18.7) on Nov. 6 using the new
telescope TRAPPIST at the European Southern Observatory (La Silla). A
series of 3-s exposures of a field of size 3' x 3' (1".3/pixel) were
secured in fast-readout mode (with a deadtime of 1.5 s), starting at
01h50m UT for one hour. Seven frames centered at 02h19m34s UT allowed
them to derive the start of the occultation as 02h19m16s.75 +/- 0s.75
and the end as 02h19m47s.6 +/- 0s.2, for a total occultation time of
30.4 +/- 1.0 seconds. The predictions (see above) made by the Rio de
Janeiro group (Assafin et al., Nov. 5) and by J. L. Ortiz estimated the
time of the occultation around 02h18m UT for Chile, in good agreement
with the observations. During the occultation, a point source is
detected with a magnitude corresponding to that of Eris. A small flux
increase was also seen at the middle of the occultation, which might
result from refraction in Eris' atmosphere (Elliot and Olkin 1996,
Ann. Rev. Earth Planet. Sci. 24, 89). Eris is by far the most-remote
solar-system object observed to date via stellar occultation, with a
geocentric distance of about 96 AU. TRAPPIST is a project driven by
the University of Liege, in close collaboration with the Observatory
of Geneva, supported by the Belgian Fund for Scientific Research and
the Swiss National Science Foundation.
---------------------------------------------------------
Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational
Lenses. VIII. Deconvolution of high resolution near-IR images and
simple mass models for 7 gravitationally lensed quasars
Authors: Chantry, V.; Sluse, D.; Magain, P.
2010A&A...522A..95C Altcode: 2010arXiv1007.3142C
<BR /> Aims: We attempt to place very accurate positional constraints
on seven gravitationally lensed quasars currently being monitored
by the COSMOGRAIL collaboration, and shape parameters for the light
distribution of the lensing galaxy. We attempt to determine simple
mass models that reproduce the observed configuration and predict time
delays. We finally test, for the quads, whether there is evidence of
astrometric perturbations produced by substructures in the lensing
galaxy, which may preclude a good fit with the simple models. <BR />
Methods: We apply the iterative MCS deconvolution method to near-IR
HST archival data of seven gravitationally lensed quasars. This
deconvolution method allows us to differentiate the contributions of
the point sources from those of extended structures such as Einstein
rings. This method leads to an accuracy of 1-2 mas in the relative
positions of the sources and lens. The limiting factor of the method
is the uncertainty in the instrumental geometric distortions. We then
compute mass models of the lensing galaxy using state-of-the-art
modeling techniques. <BR /> Results: We determine the relative
positions of the lensed images and lens shape parameters of seven
lensed quasars: HE 0047-1756, RX J1131-1231, SDSS J1138+0314, SDSS
J1155+6346, SDSS J1226-0006, WFI J2026-4536, and HS 2209+1914. The
lensed image positions are derived with 1-2 mas accuracy. Isothermal
and de Vaucouleurs mass models are calculated for the whole sample. The
effect of the lens environment on the lens mass models is taken into
account with a shear term. Doubly imaged quasars are equally well
fitted by each of these models. A large amount of shear is necessary
to reproduce SDSS J1155+6346 and SDSS J1226-006. In the latter case, we
identify a nearby galaxy as the dominant source of shear. The quadruply
imaged quasar SDSS J1138+0314 is reproduced well by simple lens models,
which is not the case for the two other quads, RX J1131-1231 and WFI
J2026-4536. This might be the signature of astrometric perturbations
caused by massive substructures in the galaxy, which are unaccounted
for by the models. Other possible explanations are also presented. <P
/>Based on observations made with the NASA/ESA HST Hubble Space
Telescope, obtained from the data archive at the Space Science
Institute, which is operated by AURA, the Association of Universities
for Research in Astronomy, Inc., under NASA contract NAS-5-26555.
---------------------------------------------------------
Title: The 3/4 July 2010 Pluto Stellar-Occultation Observations
Authors: Pasachoff, Jay M.; Elliot, J. L.; Souza, S. P.; Person, M. J.;
Zuluaga, C.; Bosh, A. S.; Zangari, A. M.; Jensen-Clem, R.; Lockhart,
M.; Gulbis, A. A. S.; Rojo, P.; Lu, M.; Malamut, C.; Levine, S. E.;
Ivarsen, K. M.; Reichart, D. E.; LaCluyze, A. P.; Nysewander, M. C.;
Haislip, J. B.; MacDonald, R. K. D.; Bailyn, C. D.; Emilio, M.; Jehin,
E.; Gillon, M.; Manfroid, J.; Chantry, V.; Magain, P.; Hutsemekers,
D.; Queloz, D.
2010DPS....42.2002P Altcode: 2010BAAS...42Q.983P
Continuing our monitoring of Pluto's atmospheric temperature and
pressure, previously shown by us to be increasing (Elliot et al.,
Nature 424, 165, 2003; Pasachoff et al., AJ 129, 1718, 2005)
and subsequently found by us to be leveling off (Elliot et al.,
AJ 134, 1, 2007), we report on a stellar occultation by Pluto of
UCAC2 mag=15.3, observed from South America and Africa on 4 July
2010 UT. Success was achieved with a 0.45 m at Cerro Calan using
one of our POETS (Portable Occultation, Eclipse, and Transit System;
Souza et al. PASP 118, 1550, 2006), a 1.0 SMARTS (Small and Medium
Aperture Research Telescope System) at Cerro Tololo, four 0.6 m
telescopes of PROMPT (Panchromatic Robotic Optical Monitoring and
Polarimetry Telescopes) on Cerro Tololo, and TRAPPIST's (TRansiting
Planets and Planetesimals Small Telescope) 0.6-m telescope on La
Silla in Chile; the 0.35 m telescope of U. Ponta Grossa, Brazil;
and the 0.75-m ATOM (Automatic Telescope for Optical Monitoring),
Namibia, using POETS. Winds prevented opening the 6.5 m Magellan/Clay
telescope on Las Campanas, Chile, with its own frame-transfer camera,
and clouds obscured the 1.9 m telescope at Sutherland, South Africa,
which had POETS. With shadow velocity 23.6 km/s, it was a rapid event:
maximum occultation <2 minutes. <P />The observations were supported
in part by grants NNX08AO50G to Williams College and NNX10AB27G to
MIT from NASA's Planetary Astronomy Division, and NNH08AI17I to USNO
for astrometry. Student participation was supported in part by NASA's
Massachusetts Space Grant and NSF's REU. Japan's government donated
U. Chile's Cerro Calan Goto telescope. PROMPT observations were made
possible by the Robert Martin Ayers Science Fund. TRAPPIST is a project
driven by the University of Liège, in close collaboration with the
Observatory of Geneva, supported by the Belgian Fund for Scientific
Research and the Swiss National Science Foundation.
---------------------------------------------------------
Title: TRAPPIST : un télescope liégeois à la découverte des
systèmes planétaires
Authors: Jehin, E.; Gillon, M.; Chantry, V.; Magain, P.
2010Ciel...72..326J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Spitzer search for the transits of HARPS low-mass
planets. I. No transit for the super-Earth HD 40307b
Authors: Gillon, M.; Deming, D.; Demory, B. -O.; Lovis, C.; Seager,
S.; Mayor, M.; Pepe, F.; Queloz, D.; Segransan, D.; Udry, S.; Delmelle,
S.; Magain, P.
2010A&A...518A..25G Altcode: 2010arXiv1002.4707G
We used Spitzer and its IRAC camera to search for the transit of the
super-Earth HD 40307b. The hypothesis that the planet transits could not
be firmly discarded from our first photometric monitoring of a transit
window because of the uncertainty coming from the modeling of the
photometric baseline. To obtain a firm result, two more transit windows
were observed and a global Bayesian analysis of the three IRAC time
series and the HARPS radial velocities was performed. Unfortunately,
the hypothesis that the planet transited during the observed phase
window is firmly rejected, while the probability that the planet
does transit but that the eclipse was missed by our observations
is nearly negligible (0.26%). <P />The photometric time series
used in this work are only available in electronic form at the CDS
via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A
href="http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/518/A25">http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/518/A25</A>
---------------------------------------------------------
Title: VizieR Online Data Catalog: Transits of HD40307b by Spitzer
(Gillon+, 2010)
Authors: Gillon, M.; Deming, D.; Demory, B. -O.; Lovis, C.; Seager,
S.; Mayor, M.; Pepe, F.; Queloz, D.; Segransan, D.; Udry, S.; Delmelle,
S.; Magain, P.
2010yCat..35180025G Altcode: 2010yCat..35189025G
We used Spitzer and its IRAC camera to search for the transit of the
super-Earth HD 40307b. The hypothesis that the planet transits could not
be firmly discarded from our first photometric monitoring of a transit
window because of the uncertainty coming from the modeling of the
photometric baseline. To obtain a firm result, two more transit windows
were observed and a global Bayesian analysis of the three IRAC time
series and the HARPS radial velocities was performed. Unfortunately,
the hypothesis that the planet transited during the observed phase
window is firmly rejected, while the probability that the planet does
transit but that the eclipse was missed by our observations is nearly
negligible (0.26%) <P />(3 data files).
---------------------------------------------------------
Title: Deep near-infrared imaging of the HE0450-2958 system
Authors: Letawe, G.; Magain, P.
2010A&A...515A..84L Altcode: 2010arXiv1003.3746L
Context. The QSO HE0450-2958 and the companion galaxy with which it
is interacting, both ultra luminous in the infrared, have been the
subject of much attention in recent years, as the quasar host galaxy
remained undetected. This led to various interpretations on QSO and
galaxy formation and co-evolution, such as black hole ejection, jet
induced star formation, dust obscured galaxy, or normal host below the
detection limit. <BR /> Aims: We carried out deep observations in the
near-IR in order to solve the puzzle concerning the existence of any
host. <BR /> Methods: The object was observed with the ESO VLT and
HAWK-I in the near-IR J-band for 8 h. The images have been processed
with the MCS deconvolution method, permitting accurate subtraction
of the QSO light from the observations. <BR /> Results: The compact
emission region situated close to the QSO, called the blob, which
previously showed only gas emission lines in the optical spectra, is
now detected in our near-IR images. Its high brightness implies that
stars likely contribute to the near-IR emission. The blob might thus
be interpreted as an off-centre, bright and very compact host galaxy,
involved in a violent collision with its companion.
---------------------------------------------------------
Title: Eclipsing binary candidates in Corot-IRa01 field (Carpano+,
2009)
Authors: Carpano, S.; Cabrera, J.; Alonso, R.; Barge, P.; Aigrain, S.;
Almenara, J. -M.; Borde, P.; Bouchy, F.; Carone, L.; Deeg, H. J.;
de La, Reza R.; Deleuil, M.; Dvorak, R.; Erikson, A.; Fressin,
F.; Fridlund, M.; Gondoin, P.; Guillot, T.; Hatzes, A.; Jorda, L.;
Lammer, H.; Leger, A.; Llebaria, A.; Magain, P.; Moutou, C.; Ofir, A.;
Ollivier, M.; Janot-Pacheco, E.; Paetzold, M.; Pont, F.; Queloz, D.;
Rauer, H.; Regulo, C.; Renner, S.; Rouan, D.; Samuel, B.; Schneider,
J.; Wuchterl, G.
2010yCat..35060491C Altcode:
CoRoT observed its first field from early February 2008 until early
April, for approximatively 60 days. The run code "IRa01" is explained as
following. The "IR" means "initial run" in contrast to the subsequent
"long runs" (LR) and "short runs" (SR). The third letter refers to
the direction with respect to the Galactic center ("a", as in this
case, anticenter or "c" Galactic center). The last two digits are the
sequence for this type of observation (01 being the first one). <P
/>(1 data file).
---------------------------------------------------------
Title: The Power of Deconvolution for Study of QSO Host Galaxies
Authors: Letawe, Géraldine; Letawe, Yannick; Magain, Pierre
2010IAUS..267..117L Altcode:
The major challenge in studying QSO host galaxies is to remove the
QSO contribution, which often outshines the whole system. Our group
has acquired the technical ability to handle such data, for images
and slit spectroscopy, as well as integral field spectroscopy. We
review here the major techniques developed by our team, and their
latest applications. We are open for collaboration with other teams
to spread the use of these powerful techniques.
---------------------------------------------------------
Title: Study of a homogeneous QSO sample: relations between the QSO
and its host galaxy
Authors: Letawe, Y.; Letawe, G.; Magain, P.
2010MNRAS.403.2088L Altcode: 2010arXiv1001.0463L; 2010MNRAS.tmp..217L
We analyse a sample of 69 quasi-stellar objects (QSOs) which have
been randomly selected in a complete sample of 104 QSOs (R <=
18,0.142 < z < 0.198,δ < 10°). 60 have been observed with
the NTT/SUSI2 at La Silla, through two filters in the optical band
(WB 655 and V 812), and the remaining nine are taken from archive data
bases. The filter V 812 contains the redshifted Hβ and forbidden
[OIII] emission lines, while WB 655 covers a spectral region devoid
of emission lines, thus measuring the QSO and stellar continua. The
contributions of the QSO and the host are separated thanks to the MCS
deconvolution algorithm, allowing a morphological classification of the
host, and the computation of several parameters such as the host and
nucleus absolute V magnitude, distance between the luminosity centre of
the host and the QSO and colour of the host and nucleus. We define a
new asymmetry coefficient, independent of any galaxy models and well
suited for QSO host studies. The main results from this study are
(i) 25 per cent of the total number of QSO hosts are spirals, 51 per
cent are ellipticals and 60 per cent show signs of interaction, (ii)
highly asymmetric systems tend to have a higher gas ionization level and
(iii) elliptical hosts contain a substantial amount of ionized gas and
some show off-nuclear activity. These results agree with hierarchical
models merger driven evolution. <P />Based on observations collected
at the European Organisation for Astronomical Research in the Southern
Hemisphere, Chile, under programme IDs 77.B-0229 and 78.B-0081. <P
/>E-mail: gletawe@ulg.ac.be
---------------------------------------------------------
Title: Transiting exoplanets from the CoRoT space
mission. IX. CoRoT-6b: a transiting “hot Jupiter” planet in an
8.9d orbit around a low-metallicity star
Authors: Fridlund, M.; Hébrard, G.; Alonso, R.; Deleuil, M.;
Gandolfi, D.; Gillon, M.; Bruntt, H.; Alapini, A.; Csizmadia, Sz.;
Guillot, T.; Lammer, H.; Aigrain, S.; Almenara, J. M.; Auvergne, M.;
Baglin, A.; Barge, P.; Bordé, P.; Bouchy, F.; Cabrera, J.; Carone,
L.; Carpano, S.; Deeg, H. J.; de La Reza, R.; Dvorak, R.; Erikson,
A.; Ferraz-Mello, S.; Guenther, E.; Gondoin, P.; den Hartog, R.;
Hatzes, A.; Jorda, L.; Léger, A.; Llebaria, A.; Magain, P.; Mazeh,
T.; Moutou, C.; Ollivier, M.; Pätzold, M.; Queloz, D.; Rauer, H.;
Rouan, D.; Samuel, B.; Schneider, J.; Shporer, A.; Stecklum, B.;
Tingley, B.; Weingrill, J.; Wuchterl, G.
2010A&A...512A..14F Altcode: 2010arXiv1001.1426F
The CoRoT satellite exoplanetary team announces its sixth transiting
planet in this paper. We describe and discuss the satellite observations
as well as the complementary ground-based observations - photometric and
spectroscopic - carried out to assess the planetary nature of the object
and determine its specific physical parameters. The discovery reported
here is a “hot Jupiter” planet in an 8.9d orbit, 18 stellar radii,
or 0.08 AU, away from its primary star, which is a solar-type star
(F9V) with an estimated age of 3.0 Gyr. The planet mass is close to
3 times that of Jupiter. The star has a metallicity of 0.2 dex lower
than the Sun, and a relatively high <SUP>7</SUP>Li abundance. While
the light curve indicates a much higher level of activity than, e.g.,
the Sun, there is no sign of activity spectroscopically in e.g.,
the [Ca ii] H&K lines. <P />The CoRoT space mission, launched on
December 27, 2006, has been developed and is being operated by CNES,
with the contribution of Austria, Belgium, Brazil, ESA, The Research
and Scientific Support Department of ESA, Germany and Spain.
---------------------------------------------------------
Title: The thermal emission of the young and massive planet CoRoT-2b
at 4.5 and 8 μm
Authors: Gillon, M.; Lanotte, A. A.; Barman, T.; Miller, N.; Demory,
B. -O.; Deleuil, M.; Montalbán, J.; Bouchy, F.; Collier Cameron, A.;
Deeg, H. J.; Fortney, J. J.; Fridlund, M.; Harrington, J.; Magain,
P.; Moutou, C.; Queloz, D.; Rauer, H.; Rouan, D.; Schneider, J.
2010A&A...511A...3G Altcode: 2009arXiv0911.5087G
We report measurements of the thermal emission of the young and massive
planet CoRoT-2b at 4.5 and 8 μm with the Spitzer Infrared Array Camera
(IRAC). Our measured occultation depths are 0.510±0.042% at 4.5 and
0.41±0.11% at 8 μm. In addition to the CoRoT optical measurements,
these planet/star flux ratios indicate a poor heat distribution on the
night side of the planet and agree better with an atmosphere free of
temperature inversion layer. Still, such an inversion is not definitely
ruled out by the observations and a larger wavelength coverage is
required to remove the current ambiguity. Our global analysis of CoRoT,
Spitzer, and ground-based data confirms the high mass and large size of
the planet with slightly revised values (M_p = 3.47±0.22 M<SUB>J</SUB>,
R_p = 1.466±0.044 R<SUB>J</SUB>). We find a small but significant
offset in the timing of the occultation when compared to a purely
circular orbital solution, leading to e \cosω = -0.00291±0.00063
where e is the orbital eccentricity and ω is the argument of
periastron. Constraining the age of the system to at most a few hundred
Myr and assuming that the non-zero orbital eccentricity does not come
from a third undetected body, we modeled the coupled orbital-tidal
evolution of the system with various tidal Q values, core sizes, and
initial orbital parameters. For Q_s' = 10<SUP>5</SUP>-10<SUP>6</SUP>,
our modeling is able to explain the large radius of CoRoT-2b if
Q_p'≤ 10<SUP>5.5</SUP> through a transient tidal circularization and
corresponding planet tidal heating event. Under this model, the planet
will reach its Roche limit within 20 Myr at most. <P />Based on data
collected with the VLT/FORS2 instrument at ESO Paranal Observatory,
Chile (programs 081.C-0413(B)). <P />The photometric timeseries
used in this work are only available in electronic form at the CDS
via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A
href="http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/511/A3">http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/511/A3</A>
---------------------------------------------------------
Title: Transit timing analysis of CoRoT-1b
Authors: Csizmadia, Sz.; Renner, S.; Barge, P.; Agol, E.; Aigrain,
S.; Alonso, R.; Almenara, J. -M.; Bonomo, A. S.; Bordé, P.; Bouchy,
F.; Cabrera, J.; Deeg, H. J.; de La Reza, R.; Deleuil, M.; Dvorak, R.;
Erikson, A.; Guenther, E. W.; Fridlund, M.; Gondoin, P.; Guillot, T.;
Hatzes, A.; Jorda, L.; Lammer, H.; Lázaro, C.; Léger, A.; Llebaria,
A.; Magain, P.; Moutou, C.; Ollivier, M.; Pätzold, M.; Queloz, D.;
Rauer, H.; Rouan, D.; Schneider, J.; Wuchterl, G.; Gandolfi, D.
2010A&A...510A..94C Altcode: 2009arXiv0911.3585C
Context. CoRoT, the pioneer space-based transit search, steadily
provides thousands of high-precision light curves with continuous
time sampling over periods of up to 5 months. The transits of a planet
perturbed by an additional object are not strictly periodic. By studying
the transit timing variations (TTVs), additional objects can be detected
in the system. <BR /> Aims: A transit timing analysis of CoRoT-1b is
carried out to constrain the existence of additional planets in the
system. <BR /> Methods: We used data obtained by an improved version of
the CoRoT data pipeline (version 2.0). Individual transits were fitted
to determine the mid-transit times, and we analyzed the derived O-C
diagram. N-body integrations were used to place limits on secondary
planets. <BR /> Results: No periodic timing variations with a period
shorter than the observational window (55 days) are found. The presence
of an Earth-mass Trojan is not likely. A planet of mass greater than
~1 Earth mass can be ruled out by the present data if the object is
in a 2:1 (exterior) mean motion resonance with CoRoT-1b. Considering
initially circular orbits: (i) super-Earths (less than 10 Earth-masses)
are excluded for periods less than about 3.5 days; (ii) Saturn-like
planets can be ruled out for periods less than about 5 days; (iii)
Jupiter-like planets should have a minimum orbital period of about 6.5
days. <P />Based on observations obtained with CoRoT, a space project
operated by the French Space Agency, CNES, with participation of the
Science Programs of ESA, ESTEC/RSSD, Austria, Belgium, Brazil, Germany,
and Spain.
---------------------------------------------------------
Title: High-dispersion infrared spectroscopic observations of comet
8P/Tuttle with VLT/CRIRES
Authors: Kobayashi, H.; Bockelée-Morvan, D.; Kawakita, H.; Dello
Russo, N.; Jehin, E.; Manfroid, J.; Smette, A.; Hutsemékers,
D.; Stüwe, J.; Weiler, M.; Arpigny, C.; Biver, N.; Cochran, A.;
Crovisier, J.; Magain, P.; Sana, H.; Schulz, R.; Vervack, R. J.;
Weaver, H.; Zucconi, J. -M.
2010A&A...509A..80K Altcode:
We report on the composition of the Halley-family comet (HFC) 8P/Tuttle
investigated with high-dispersion near-infrared spectroscopic
observations. The observations were carried out at the ESO VLT
(Very Large Telescope) with the CRIRES instrument as part of a
multi-wavelength observation campaign of 8P/Tuttle performed in late
January and early February 2008. Radar observations suggested that
8P/Tuttle is a contact binary, and it was proposed that these components
might be heterogeneous in chemistry. We determined mixing ratios of
organic volatiles with respect to H<SUB>2</SUB>O and found that mixing
ratios were consistent with previous near infrared spectroscopic
observations obtained in late December 2007 and in late January
2008. It has been suggested that because 8P/Tuttle is a contact binary,
it might be chemically heterogeneous. However, we find no evidence
for chemical heterogeneity within the nucleus of 8P/Tuttle. We also
compared the mixing ratios of organic molecules in 8P/Tuttle with those
of both other HFCs and long period comets (LPCs) and found that HCN,
C<SUB>2</SUB>H<SUB>2</SUB>, and C<SUB>2</SUB>H<SUB>6</SUB> are depleted
whereas CH<SUB>4</SUB> and CH<SUB>3</SUB>OH have normal abundances. This
may indicate that 8P/Tuttle was formed in a different region of the
early solar nebula than other HFCs and LPCs. We estimated the conversion
efficiency from C<SUB>2</SUB>H<SUB>2</SUB> to C<SUB>2</SUB>H<SUB>6</SUB>
by hydrogen addition reactions on cold grains by employing the
C<SUB>2</SUB>H<SUB>6</SUB>/(C<SUB>2</SUB>H<SUB>6</SUB>+C<SUB>2</SUB>H<SUB>2</SUB>)
ratio. The
C<SUB>2</SUB>H<SUB>6</SUB>/(C<SUB>2</SUB>H<SUB>6</SUB>+C<SUB>2</SUB>H<SUB>2</SUB>)
ratio in 8P/Tuttle is consistent with the ratios found in other
HFCs and LPCs within the error bars. We also discuss the source of
C<SUB>2</SUB> and CN based on our observations and conclude that the
abundances of C<SUB>2</SUB>H<SUB>2</SUB> and C<SUB>2</SUB>H<SUB>6</SUB>
are insufficient to explain the C<SUB>2</SUB> abundances in comet
8P/Tuttle and that the abundance of HCN is insufficient to explain
the CN abundances in the comet, so at least one additional parent is
needed for each species, as pointed out in previous study. <P />Based on
observations collected at the European Southern Observatory, Paranal,
Chile (ESO Prog. 080.C-0615 and 280.C-5053).We regret to note the
death of Dr. J. -M. Zucconi in 2009 May.
---------------------------------------------------------
Title: Eclipsing binaries in CoRoT-LRc01 field (Cabrera+, 2009)
Authors: Cabrera, J.; Fridlund, M.; Ollivier, M.; Gandolfi, D.;
Csizmadia, Sz.; Alonso, R.; Aigrain, S.; Alapini, A.; Almenara, J. -M.;
Barge, P.; Bonomo, A. S.; Borde, P.; Bouchy, F.; Bruntt, H.; Carone,
L.; Carpano, S.; Deeg, H. J.; de La, Reza R.; Deleuil, M.; Dvorak,
R.; Erikson, A.; Gillon, M.; Gondoin, P.; Guenther, E. W.; Guillot,
T.; Hartmann, M.; Hatzes, A.; Hebrard, G.; Jorda, L.; Lammer, H.;
Leger, A.; Llebaria, A.; Lovis, C.; Magain, P.; Mayor, M.; Mazeh,
T.; Moutou, C.; Ofir, A.; Paetzold, M.; Pepe, F.; Pont, F.; Queloz,
D.; Rabus, M.; Rauer, H.; Regulo, C.; Renner, S.; Rouan, D.; Samuel,
B.; Santerne, A.; Schneider, J.; Shporer, A.; Stecklum, B.; Tingley,
B.; Udry, S.; Wuchterl, G.
2010yCat..35060501C Altcode:
The 11408 targets observed by CoRoT were selected using the information
gathered in the database Exo-Dat (Deleuil et al. 2009AJ....138..649D;
Meunier et al. 2007, ASP Conf., 376, 339), built with dedicated ground
based photometric observations in the visible and near IR bands from
2MASS catalog. <P />(3 data files).
---------------------------------------------------------
Title: Study of Quasar Host Galaxies Combining HST/ACS Images and
VLT Spectra
Authors: Letawe, Yannick; Letawe, Géraldine; Magain, Pierre
2010ASSP...15..197L Altcode: 2010ihea.book..197L
We present the results of a study of the host galaxies of a few bright
low redshift quasars, based on a combination of high resolution HST/ACS
images with deep VLT spectra. Using a version of the MCS deconvolution
algorithm specially adapted to HST images, the light from the central
point source can be efficiently removed, which allows to study the
environment of the quasar down to a few hundreds of parsecs from
the center. In a similar way, the spectra can be separated into a
quasar contribution and a spatially resolved slit spectrum of the
host galaxy. Combining the images and spectra allows to carry out
a detailed analysis of the immediate environment of the quasar:
excitation and ionization state of the gas, dynamics… Up to now,
this method has been applied to six quasars, including the peculiar
HE0450-2958 (Magain et al. in Nature 437:381, 2005), for which no host
galaxy could be detected.
---------------------------------------------------------
Title: VizieR Online Data Catalog: Light curves of CoRoT-2 in z-band,
4.5um and 8um (Gillon+, 2010)
Authors: Gillon, M.; Lanotte, A. A.; Barman, T.; Miller, N.; Demory,
B. -O.; Deleuil, M.; Montalban, J.; Bouchy, F.; Collier, Cameron A.;
Deeg, H. J.; Fortney, J. J.; Fridlund, M.; Harrington, J.; Magain,
P.; Moutou, C.; Queloz, D.; Rauer, H.; Rouan, D.; Schneider, J.
2009yCat..35110003G Altcode: 2009yCat..35119003G
Photometric time series obtained for CoRoT-2 with the VLT/FORS2 camera
in z band during a transit of the planet CoRoT-2b and with the SST/IRAC
camera at 4.5 and 8um during an occultation of the same planet. <P
/>(3 data files).
---------------------------------------------------------
Title: Transiting exoplanets from the CoRoT space mission. VII. The
“hot-Jupiter”-type planet CoRoT-5b
Authors: Rauer, H.; Queloz, D.; Csizmadia, Sz.; Deleuil, M.; Alonso,
R.; Aigrain, S.; Almenara, J. M.; Auvergne, M.; Baglin, A.; Barge,
P.; Bordé, P.; Bouchy, F.; Bruntt, H.; Cabrera, J.; Carone, L.;
Carpano, S.; de La Reza, R.; Deeg, H. J.; Dvorak, R.; Erikson, A.;
Fridlund, M.; Gandolfi, D.; Gillon, M.; Guillot, T.; Guenther, E.;
Hatzes, A.; Hébrard, G.; Kabath, P.; Jorda, L.; Lammer, H.; Léger,
A.; Llebaria, A.; Magain, P.; Mazeh, T.; Moutou, C.; Ollivier, M.;
Pätzold, M.; Pont, F.; Rabus, M.; Renner, S.; Rouan, D.; Shporer,
A.; Samuel, B.; Schneider, J.; Triaud, A. H. M. J.; Wuchterl, G.
2009A&A...506..281R Altcode: 2009arXiv0909.3397R
Aims: The CoRoT space mission continues to photometrically monitor
about 12 000 stars in its field-of-view for a series of target fields
to search for transiting extrasolar planets ever since 2007. Deep
transit signals can be detected quickly in the “alarm-mode”
in parallel to the ongoing target field monitoring. CoRoT's first
planets have been detected in this mode. <BR />Methods: The CoRoT
raw lightcurves are filtered for orbital residuals, outliers,
and low-frequency stellar signals. The phase folded lightcurve
is used to fit the transit signal and derive the main planetary
parameters. Radial velocity follow-up observations were initiated to
secure the detection and to derive the planet mass. <BR />Results:
We report the detection of CoRoT-5b, detected during observations
of the LRa01 field, the first long-duration field in the galactic
anti-center direction. CoRoT-5b is a “hot Jupiter-type”
planet with a radius of 1.388<SUP>+0.046</SUP><SUB>-0.047</SUB>
R_Jup, a mass of 0.467<SUP>+0.047</SUP><SUB>-0.024</SUB> M_Jup, and
therefore, a mean density of 0.217<SUP>+0.031</SUP><SUB>-0.025</SUB>
g cm<SUP>-3</SUP>. The planet orbits an F9V star of 14.0
mag in 4.0378962 ± 0.0000019 days at an orbital distance of
0.04947<SUP>+0.00026</SUP><SUB>-0.00029</SUB> AU. <P />Observations
made with SOPHIE spectrograph at the Observatoire de Haute Provence
(07B.PNP.MOUT), France, and HARPS spectrograph at ESO La Silla
Observatory (072.C-0488(E), 082.C-0312(A)), and partly based on
observations made at the Anglo-Australian Telescope. The CoRoT space
mission, launched on December 27, 2006, was developed and is operated by
CNES, with the contribution of Austria, Belgium, Brasil, ESA, Germany,
and Spain.
---------------------------------------------------------
Title: VLT transit and occultation photometry for the bloated
planet CoRoT-1b
Authors: Gillon, M.; Demory, B. -O.; Triaud, A. H. M. J.; Barman, T.;
Hebb, L.; Montalbán, J.; Maxted, P. F. L.; Queloz, D.; Deleuil, M.;
Magain, P.
2009A&A...506..359G Altcode: 2009arXiv0905.4571G
We present VLT eclipse photometry for the giant planet CoRoT-1b. We
observed a transit in the R-band filter and an occultation in
a narrow filter centered on 2.09 μm. Our analysis of this new
photometry and published radial velocities, in combination
with stellar-evolutionary modeling, leads to a planetary
mass and radius of 1.07<SUP>+0.13</SUP><SUB>-0.18</SUB>
M_Jup and 1.45<SUP>+0.07</SUP><SUB>-0.13</SUB> R_Jup,
confirming the very low density previously deduced from CoRoT
photometry. The large occultation depth that we measure at 2.09
μm (0.278<SUP>+0.043</SUP><SUB>-0.066</SUB>%) is consistent
with thermal emission and is better reproduced by an atmospheric
model with no redistribution of the absorbed stellar flux to the
night side of the planet. <P />Based on data collected with the
VLT/FORS2 and VLT/HAWK-I instruments at ESO Paranal Observatory,
Chile (programs 080.C-0661(B) and 382.C-0642(A)). The photometric
time-series used in this work are only available in electronic form
at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5)
or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/506/359
---------------------------------------------------------
Title: Planetary transit candidates in CoRoT-LRc01 field
Authors: Cabrera, J.; Fridlund, M.; Ollivier, M.; Gandolfi, D.;
Csizmadia, Sz.; Alonso, R.; Aigrain, S.; Alapini, A.; Almenara, J. -M.;
Barge, P.; Bonomo, A. S.; Bordé, P.; Bouchy, F.; Bruntt, H.; Carone,
L.; Carpano, S.; Deeg, H. J.; de La Reza, R.; Deleuil, M.; Dvorak,
R.; Erikson, A.; Gillon, M.; Gondoin, P.; Guenther, E. W.; Guillot,
T.; Hartmann, M.; Hatzes, A.; Hebrard, G.; Jorda, L.; Lammer, H.;
Léger, A.; Llebaria, A.; Lovis, C.; Magain, P.; Mayor, M.; Mazeh,
T.; Moutou, C.; Ofir, A.; Pätzold, M.; Pepe, F.; Pont, F.; Queloz,
D.; Rabus, M.; Rauer, H.; Régulo, C.; Renner, S.; Rouan, D.; Samuel,
B.; Santerne, A.; Schneider, J.; Shporer, A.; Stecklum, B.; Tingley,
B.; Udry, S.; Wuchterl, G.
2009A&A...506..501C Altcode:
Aims: We present here the list of planetary transit candidates detected
in the first long run observed by CoRoT: LRc01, towards the galactic
center in the direction of Aquila, which lasted from May to October
2007. <BR />Methods: we analyzed 3719 (33%) sources in the chromatic
bands and 7689 in the monochromatic band. Instrumental noise and the
stellar variability were treated with several detrending tools, on
which subsequently several transit search algorithms were applied. <BR
/>Results: Forty two sources were classified as planetary transit
candidates and up to now 26 cases have been solved. One planet
(CoRoT-2b) and one brown-dwarf (CoRoT-3b) have been the subjects
of detailed publications. <P />The CoRoT space mission, launched
on December 27 2006, was developed and is operated by CNES, with
contributions from Austria, Belgium, Brazil, ESA, Germany and Spain. The
first CoRoT data are available to the community from the CoRoT archive:
http://idoc-corot.ias.u-psud.fr.
---------------------------------------------------------
Title: Planetary transit candidates in the CoRoT initial run:
resolving their nature
Authors: Moutou, C.; Pont, F.; Bouchy, F.; Deleuil, M.; Almenara,
J. M.; Alonso, R.; Barbieri, M.; Bruntt, H.; Deeg, H. J.; Fridlund,
M.; Gandolfi, D.; Gillon, M.; Guenther, E.; Hatzes, A.; Hébrard, G.;
Loeillet, B.; Mayor, M.; Mazeh, T.; Queloz, D.; Rabus, M.; Rouan, D.;
Shporer, A.; Udry, S.; Aigrain, S.; Auvergne, M.; Baglin, A.; Barge,
P.; Benz, W.; Bordé, P.; Carpano, S.; de La Reza, R.; Dvorak, R.;
Erikson, A.; Gondoin, P.; Guillot, T.; Jorda, L.; Kabath, P.; Lammer,
H.; Léger, A.; Llebaria, A.; Lovis, C.; Magain, P.; Ollivier, M.;
Pätzold, M.; Pepe, F.; Rauer, H.; Schneider, J.; Wuchterl, G.
2009A&A...506..321M Altcode:
With the release of CoRoT lightcurves of the Initial Run IRa01, 50
transiting planetary candidates have been published in a companion
paper. About twenty of them were identified as binary stars from
the CoRoT lightcurve itself. Complementary observations were
conducted for 29 candidates, including ground-based photometry and
radial-velocity measurements. Two giant planets were identified and
fully characterized. Nineteen binaries are recognized, from which 10
are background eclipsing binaries in the CoRoT mask or triple systems,
diluted by the main CoRoT target. Eight cases remain of unclear
origin, one of them still being a planetary candidate. Comparison
with simulations shows that the actual threshold of confirmed planet
detection in this field does not yet fulfill the expectations, and
a number of reasons are invoked, like the ranking process based
on lightcurve analyses, and the strategy and limits of follow-up
observations for targets fainter than magnitude 15. <P />Based on data
obtained at Observatoire de Haute Provence with SOPHIE and with HARPS
on the ESO 3.6 m telescope at La Silla Observatory. The CoRoT space
mission, launched on December 27th 2006, has been developed and is
operated by CNES, with the contribution of Austria, Belgium, Brazil ,
ESA (RSSD and Science Programme), Germany and Spain. <P />Tables 2 to
13, 15 to 17 and Figs. 4 to 7 are only available in electronic form
at http://www.aanda.org
---------------------------------------------------------
Title: Planetary transit candidates in Corot-IRa01 field
Authors: Carpano, S.; Cabrera, J.; Alonso, R.; Barge, P.; Aigrain, S.;
Almenara, J. -M.; Bordé, P.; Bouchy, F.; Carone, L.; Deeg, H. J.;
de La Reza, R.; Deleuil, M.; Dvorak, R.; Erikson, A.; Fressin,
F.; Fridlund, M.; Gondoin, P.; Guillot, T.; Hatzes, A.; Jorda,
L.; Lammer, H.; Léger, A.; Llebaria, A.; Magain, P.; Moutou, C.;
Ofir, A.; Ollivier, M.; Janot-Pacheco, E.; Pätzold, M.; Pont, F.;
Queloz, D.; Rauer, H.; Régulo, C.; Renner, S.; Rouan, D.; Samuel,
B.; Schneider, J.; Wuchterl, G.
2009A&A...506..491C Altcode: 2009arXiv0907.5150C
Context: CoRoT is a pioneering space mission devoted to the analysis
of stellar variability and the photometric detection of extrasolar
planets. <BR />Aims: We present the list of planetary transit candidates
detected in the first field observed by CoRoT, IRa01, the initial
run toward the Galactic anticenter, which lasted for 60 days. <BR
/>Methods: We analysed 3898 sources in the coloured bands and 5974
in the monochromatic band. Instrumental noise and stellar variability
were taken into account using detrending tools before applying various
transit search algorithms. <BR />Results: Fifty sources were classified
as planetary transit candidates and the most reliable 40 detections
were declared targets for follow-up ground-based observations. Two
of these targets have so far been confirmed as planets, CoRoT-1b and
CoRoT-4b, for which a complete characterization and specific studies
were performed. <P />The CoRoT space mission, launched on December
27th 2006, <P />has been developed and is operated by CNES, with
contributions from Austria, Belgium, Brazil, ESA, <P />Germany, and
Spain. Four <P />French laboratories associated with the CNRS (LESIA,
LAM, IAS ,OMP) collaborate with CNES on the satellite development. <P
/>First CoRoT data are available to the public from the CoRoT archive:
http://idoc-corot.ias.u-psud.fr.
---------------------------------------------------------
Title: Removing systematics from the CoRoT light
curves. I. Magnitude-dependent zero point
Authors: Mazeh, T.; Guterman, P.; Aigrain, S.; Zucker, S.; Grinberg,
N.; Alapini, A.; Alonso, R.; Auvergne, M.; Barbieri, M.; Barge,
P.; Bordé, P.; Bouchy, F.; Deeg, H.; de La Reza, R.; Deleuil, M.;
Dvorak, R.; Erikson, A.; Fridlund, M.; Gondoin, P.; Jorda, L.; Lammer,
H.; Léger, A.; Llebaria, A.; Magain, P.; Moutou, C.; Ollivier, M.;
Pätzold, M.; Pont, F.; Queloz, D.; Rauer, H.; Rouan, D.; Sabo, R.;
Schneider, J.; Wuchterl, G.
2009A&A...506..431M Altcode: 2009arXiv0907.2237M
This paper presents an analysis that searched for systematic effects
within the CoRoT exoplanet field light curves. The analysis identified
a systematic effect that modified the zero point of most CoRoT exposures
as a function of stellar magnitude. We could find this effect only after
preparing a set of learning light curves that were relatively free of
stellar and instrumental noise. Correcting for this effect, rejecting
outliers that appear in almost every exposure, and applying SysRem,
reduced the stellar RMS by about 20%, without attenuating transit
signals. <P />The CoRoT space mission, launched on December 27th 2006,
has been developed and is operated by CNES, with the contribution of
Austria, Belgium, Brazil, ESA, Germany, and Spain. CoRoT data become
publicly available one year after release to the Co-Is of the mission
from the CoRoT archive: http://idoc-corot.ias.u-psud.fr/.
---------------------------------------------------------
Title: Rate and nature of false positives in the CoRoT exoplanet
search
Authors: Almenara, J. M.; Deeg, H. J.; Aigrain, S.; Alonso, R.;
Auvergne, M.; Baglin, A.; Barbieri, M.; Barge, P.; Bordé, P.; Bouchy,
F.; Bruntt, H.; Cabrera, J.; Carone, L.; Carpano, S.; Catala, C.;
Csizmadia, Sz.; de La Reza, R.; Deleuil, M.; Dvorak, R.; Erikson, A.;
Fridlund, M.; Gandolfi, D.; Gillon, M.; Gondoin, P.; Guenther, E.;
Guillot, T.; Hatzes, A.; Hébrard, G.; Jorda, L.; Lammer, H.; Léger,
A.; Llebaria, A.; Loeillet, B.; Magain, P.; Mayor, M.; Mazeh, T.;
Moutou, C.; Ollivier, M.; Pätzold, M.; Pont, F.; Queloz, D.; Rauer,
H.; Régulo, C.; Renner, S.; Rouan, D.; Samuel, B.; Schneider, J.;
Shporer, A.; Wuchterl, G.; Zucker, S.
2009A&A...506..337A Altcode: 2009arXiv0908.1172A
Context: The CoRoT satellite searches for planets by applying the
transit method, monitoring up to 12 000 stars in the galactic plane
for 150 days in each observing run. This search is contaminated by
a large fraction of false positives, caused by different eclipsing
binary configurations that might be confused with a transiting
planet. <BR />Aims: We evaluate the rates and nature of false
positives in the CoRoT exoplanets search and compare our results with
semiempirical predictions. <BR />Methods: We consider the detected
binary and planet candidates in the first three extended CoRoT runs,
and classify the results of the follow-up observations completed to
verify their planetary nature. We group the follow-up results into
undiluted binaries, diluted binaries, and planets and compare their
abundances with predictions from the literature. <BR />Results: 83%
of the initial detections are classified as false positives using
only the CoRoT light-curves, the remaining 17% require follow-up
observations. Finally, 12% of the candidates in the follow-up program
are planets. The shape of the overall distribution of the false positive
rate follows previous predictions, except for candidates with transit
depths below about 0.4%. For candidates with transit depths in the
range from 0.1-0.4%, CoRoT detections are nearly complete, and this
difference from predictions is probably real and dominated by a lower
than expected abundance of diluted eclipsing binaries. <P />The CoRoT
space mission, launched on December 27th 2006, has been developed
and is operated by CNES, with the contribution of Austria, Belgium,
Brazil , ESA (RSSD and Science Programme), Germany and Spain.
---------------------------------------------------------
Title: Noise properties of the CoRoT data. A planet-finding
perspective
Authors: Aigrain, S.; Pont, F.; Fressin, F.; Alapini, A.; Alonso,
R.; Auvergne, M.; Barbieri, M.; Barge, P.; Bordé, P.; Bouchy,
F.; Deeg, H.; de La Reza, R.; Deleuil, M.; Dvorak, R.; Erikson,
A.; Fridlund, M.; Gondoin, P.; Guterman, P.; Jorda, L.; Lammer, H.;
Léger, A.; Llebaria, A.; Magain, P.; Mazeh, T.; Moutou, C.; Ollivier,
M.; Pätzold, M.; Queloz, D.; Rauer, H.; Rouan, D.; Schneider, J.;
Wuchter, G.; Zucker, S.
2009A&A...506..425A Altcode: 2009arXiv0903.1829A
In this short paper, we study the photometric precision of stellar
light curves obtained by the CoRoT satellite in its planet-finding
channel, with a particular emphasis on the time scales characteristic
of planetary transits. Together with other articles in the same issue
of this journal, it forms an attempt to provide the building blocks
for a statistical interpretation of the CoRoT planet and eclipsing
binary catch to date. After pre-processing the light curves so as to
minimise long-term variations and outliers, we measure the scatter
of the light curves in the first three CoRoT runs lasting more than
1 month, using an iterative non-linear filter to isolate signal on
the time scales of interest. The behaviour of the noise on 2 h time
scales is described well by a power-law with index 0.25 in R-magnitude,
ranging from 0.1 mmag at R=11.5 to 1 mmag at R=16, which is close
to the pre-launch specification, though still a factor 2-3 above the
photon noise due to residual jitter noise and hot pixel events. There
is evidence of slight degradation in the performance over time. We
find clear evidence of enhanced variability on hour time scales (at
the level of 0.5 mmag) in stars identified as likely giants from their
R magnitude and B-V colour, which represent approximately 60 and 20%
of the observed population in the directions of Aquila and Monoceros,
respectively. On the other hand, median correlated noise levels over 2
h for dwarf stars are extremely low, reaching 0.05 mmag at the bright
end. <P />The CoRoT space mission, launched on December 27, 2006, has
been developed and is operated by the CNES, with the contribution of
Austria, Belgium, Brazil, ESA, Germany, and Spain. CoRoT data become
publicly available one year after release to the Co-Is of the mission
from the CoRoT archive: http://idoc-corot.ias.u-psud.fr/.
---------------------------------------------------------
Title: The secondary eclipse of CoRoT-1b
Authors: Alonso, R.; Alapini, A.; Aigrain, S.; Auvergne, M.; Baglin,
A.; Barbieri, M.; Barge, P.; Bonomo, A. S.; Bordé, P.; Bouchy, F.;
Chaintreuil, S.; de La Reza, R.; Deeg, H. J.; Deleuil, M.; Dvorak,
R.; Erikson, A.; Fridlund, M.; de Oliveira Fialho, F.; Gondoin, P.;
Guillot, T.; Hatzes, A.; Jorda, L.; Lammer, H.; Léger, A.; Llebaria,
A.; Magain, P.; Mazeh, T.; Moutou, C.; Ollivier, M.; Pätzold, M.;
Pont, F.; Queloz, D.; Rauer, H.; Rouan, D.; Schneider, J.; Wuchterl, G.
2009A&A...506..353A Altcode: 2009arXiv0907.1653A
The transiting planet CoRoT-1b is thought to belong to the pM-class
of planets, in which the thermal emission dominates in the optical
wavelengths. We present a detection of its secondary eclipse in
the CoRoT white channel data, whose response function goes from
~400 to ~1000 nm. We used two different filtering approaches, and
several methods to evaluate the significance of a detection of the
secondary eclipse. We detect a secondary eclipse centered within 20
min at the expected times for a circular orbit, with a depth of 0.016
± 0.006%. The center of the eclipse is translated in a 1-σ upper
limit to the planet's eccentricity of e cosω< 0.014. Under the
assumption of a zero Bond Albedo and blackbody emission from the planet,
it corresponds to a T_CoRoT = 2330<SUP>+120</SUP><SUB>-140</SUB> K. We
provide the equilibrium temperatures of the planet as a function of
the amount of reflected light. If the planet is in thermal equilibrium
with the incident flux from the star, our results imply an inefficient
transport mechanism of the flux from the day to the night sides. <P
/>Based on observations obtained with CoRoT, a space project operated
by the French Space Agency, CNES, with participation of the Science
Programme of ESA, ESTEC/RSSD, Austria, Belgium, Brazil, Germany
and Spain.
---------------------------------------------------------
Title: VizieR Online Data Catalog: CoRoT-7 radial velocities
(Queloz+, 2009)
Authors: Queloz, D.; Bouchy, F.; Moutou, C.; Hatzes, A.; Hebrard, G.;
Alonso, R.; Auvergne, M.; Baglin, A.; Barbieri, M.; Barge, P.; Benz,
W.; Borde, P.; Deeg, H. J.; Deleuil, M.; Dvorak, R.; Erikson, A.;
Ferraz Mello, S.; Fridlund, M.; Gandolfi, D.; Gillon, M.; Guenther,
E.; Guillot, T.; Jorda, L.; Hartmann, M.; Lammer, H.; Leger, A.;
Llebaria, A.; Lovis, C.; Magain, P.; Mayor, M.; Mazeh, T.; Ollivier,
M.; Patzold, M.; Pepe, F.; Rauer, H.; Rouan, D.; Schneider, J.;
Segransan, D.; Udry, S.; Wuchterl, G.
2009yCat..35060303Q Altcode:
First, a simple pre-whitening procedure was employed to find and
subsequently remove periodic signals from the complex frequency
structure of the radial velocity data. The dominant frequency in the
power spectrum was found at 23 days, which corresponds to the rotation
period of CoRoT-7. The 0.8535 day period of CoRoT-7b planetary candidate
was detected with an amplitude of 3.3m/s. <P />(1 data file).
---------------------------------------------------------
Title: The CoRoT-7 planetary system: two orbiting super-Earths
Authors: Queloz, D.; Bouchy, F.; Moutou, C.; Hatzes, A.; Hébrard, G.;
Alonso, R.; Auvergne, M.; Baglin, A.; Barbieri, M.; Barge, P.; Benz,
W.; Bordé, P.; Deeg, H. J.; Deleuil, M.; Dvorak, R.; Erikson, A.;
Ferraz Mello, S.; Fridlund, M.; Gandolfi, D.; Gillon, M.; Guenther,
E.; Guillot, T.; Jorda, L.; Hartmann, M.; Lammer, H.; Léger, A.;
Llebaria, A.; Lovis, C.; Magain, P.; Mayor, M.; Mazeh, T.; Ollivier,
M.; Pätzold, M.; Pepe, F.; Rauer, H.; Rouan, D.; Schneider, J.;
Segransan, D.; Udry, S.; Wuchterl, G.
2009A&A...506..303Q Altcode:
We report on an intensive observational campaign carried out with HARPS
at the 3.6 m telescope at La Silla on the star CoRoT-7. Additional
simultaneous photometric measurements carried out with the Euler
Swiss telescope have demonstrated that the observed radial velocity
variations are dominated by rotational modulation from cool spots
on the stellar surface. Several approaches were used to extract the
radial velocity signal of the planet(s) from the stellar activity
signal. First, a simple pre-whitening procedure was employed to find
and subsequently remove periodic signals from the complex frequency
structure of the radial velocity data. The dominant frequency in the
power spectrum was found at 23 days, which corresponds to the rotation
period of CoRoT-7. The 0.8535 day period of CoRoT-7b planetary candidate
was detected with an amplitude of 3.3 m s<SUP>-1</SUP>. Most other
frequencies, some with amplitudes larger than the CoRoT-7b signal,
are most likely associated with activity. A second approach used
harmonic decomposition of the rotational period and up to the first
three harmonics to filter out the activity signal from radial velocity
variations caused by orbiting planets. After correcting the radial
velocity data for activity, two periodic signals are detected: the
CoRoT-7b transit period and a second one with a period of 3.69 days
and an amplitude of 4 m s<SUP>-1</SUP>. This second signal was also
found in the pre-whitening analysis. We attribute the second signal
to a second, more remote planet CoRoT-7c . The orbital solution of
both planets is compatible with circular orbits. The mass of CoRoT-7b
is 4.8±0.8 (M<SUB>⊕</SUB>) and that of CoRoT-7c is 8.4± 0.9
(M<SUB>⊕</SUB>), assuming both planets are on coplanar orbits. We
also investigated the false positive scenario of a blend by a faint
stellar binary, and this may be rejected by the stability of the
bisector on a nightly scale. According to their masses both planets
belong to the super-Earth planet category. The average density of
CoRoT-7b is ρ=5.6± 1.3 g cm<SUP>-3</SUP>, similar to the Earth. The
CoRoT-7 planetary system provides us with the first insight into
the physical nature of short period super-Earth planets recently
detected by radial velocity surveys. These planets may be denser than
Neptune and therefore likely made of rocks like the Earth, or a mix
of water ice and rocks. <P />Based on observations made with HARPS
spectrograph on the 3.6-m ESO telescope and the EULER Swiss telescope at
La Silla Observatory, Chile. The HARPS results presented in this paper
(Appendix A) are available in electronic form at http://www.aanda.org
and at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5)
or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/506/303
---------------------------------------------------------
Title: A Multi-Wavelength Simultaneous Study of the Composition of
the Halley Family Comet 8P/Tuttle
Authors: Jehin, E.; Bockelée-Morvan, D.; Dello Russo, N.; Manfroid,
J.; Hutsemékers, D.; Kawakita, H.; Kobayashi, H.; Schulz, R.;
Smette, A.; Stüwe, J.; Weiler, M.; Arpigny, C.; Biver, N.; Cochran,
A.; Crovisier, J.; Magain, P.; Rauer, H.; Sana, H.; Vervack, R. J.;
Weaver, H.; Zucconi, J. -M.
2009EM&P..105..343J Altcode: 2009EM&P..tmp...38J
We report on simultaneous optical and infrared observations
of the Halley Family comet 8P/Tuttle performed with the ESO
Very Large Telescope. Such multi-wavelength and coordinated
observations are a good example of what can be done to support
space missions. From high resolution optical spectroscopy of the CN
(0,0) 388 nm and NH<SUB>2</SUB> (0,9,0) 610 nm bands using UVES
at UT2 we determined <SUP>12</SUP>C/<SUP>13</SUP>C = 90 ± 10 and
<SUP>14</SUP>N/<SUP>15</SUP>N = 150 ± 20 in CN and we derived
a nuclear spin temperature of NH<SUB>3</SUB> of 29 ± 1 K. These
values are similar to those found in Oort-Cloud and Jupiter Family
comets. From low resolution long slit spectroscopy with FORS1 at UT2
we determined the CN, C<SUB>3</SUB> and C<SUB>2</SUB> production rates
and the parent and daughter scale lengths up to 5.2 10<SUP>5</SUP>
km tailward. From high resolution IR spectroscopy with CRIRES at UT1
we measured simultaneously the production rates and mixing ratios
of H<SUB>2</SUB>O, HCN, C<SUB>2</SUB>H<SUB>2</SUB>, CH<SUB>4</SUB>,
C<SUB>2</SUB>H<SUB>6</SUB>, and CH<SUB>3</SUB>OH.
---------------------------------------------------------
Title: Near-infrared observations of the HE0450-2958 system: discovery
of a second active galactic nucleus?
Authors: Letawe, G.; Magain, P.; Chantry, V.; Letawe, Y.
2009MNRAS.396...78L Altcode: 2009arXiv0903.1718L
The quasi-stellar object (QSO) HE0450-2958 was brought to the front
scene by the non-detection of its host galaxy and strong upper limits on
the latter's luminosity. The QSO is also a powerful infrared emitter,
in gravitational interaction with a strongly distorted ultraluminous
infrared companion galaxy. We investigate the properties of the
companion galaxy, through new near- and mid-infrared observations of the
system obtained with Near Infrared Camera and Multi-Object Spectrometer
(NICMOS) onboard Hubble Space Telescope, Infrared Spectrometer and
Array Camera (ISAAC) and Very Large Telescope Imager and Spectrometer
in the Infrared (VISIR) on the European Southern Observatory Very Large
Telescope. The companion galaxy is found to harbour a point source
revealed only in the infrared, in what appears as a hole or dark patch
in the optical images. Various hypotheses on the nature of this point
source are analysed and it is found that the only plausible one is
that it is a strongly reddened active galactic nucleus hidden behind
a thick dust cloud. The hypothesis that the QSO supermassive black
hole might have been ejected from the companion galaxy in the course
of a galactic collision involving three-body black holes interaction
is also reviewed, on the basis of this new insight on a definitely
complex system. <P />Based on observations made with the ESO Very
Large Telescope at ESO Paranal Observatory, Chile, under program IDs
076.B-0693(C), 276.B-5011 and NASA/ESA HST program 10797 during cycle
15. <P />E-mail: gletawe@ulg.ac.be
---------------------------------------------------------
Title: VizieR Online Data Catalog: FORS2 and HAWKI photometry of
CoRoT-1 (Gillon+, 2009)
Authors: Gillon, M.; Demory, B. -O.; Triaud, A. H. M. J.; Barman,
T.; Hebb, L.; Montalban, J.; Maxted, P. F. L.; Queloz, D.; Deleuil,
M.; Magain, P.
2009yCat..35060359G Altcode:
We present VLT eclipse photometry for the giant planet CoRoT-1b. We
observed a transit in the R-band filter and an occultation in
a narrow filter centered on 2.09{mu}m. Our analysis of this new
photometry and published radial velocities, in combination with
stellar-evolutionary modeling, leads to a planetary mass and
radius of 1.07<SUP>+0.13</SUP><SUB>-0.18</SUB>M<SUB>{Jup}</SUB>
and 1.45<SUP>+0.07</SUP><SUB>-0.13</SUB>R_{Jup}, confirming the
very low density previously deduced from CoRoT photometry. The
large occultation depth that we measure at 2.09{mu}m
(0.278<SUP>0.043</SUP><SUB>-0.066</SUB>% ) is consistent with thermal
emission and is better reproduced by an atmospheric model with no
redistribution of the absorbed stellar flux to the night side of the
planet. <P />(2 data files).
---------------------------------------------------------
Title: Transiting exoplanets from the CoRoT space
mission. IV. CoRoT-Exo-4b: a transiting planet in a 9.2 day
synchronous orbit
Authors: Aigrain, S.; Collier Cameron, A.; Ollivier, M.; Pont, F.;
Jorda, L.; Almenara, J. M.; Alonso, R.; Barge, P.; Bordé, P.; Bouchy,
F.; Deeg, H.; de La Reza, R.; Deleuil, M.; Dvorak, R.; Erikson, A.;
Fridlund, M.; Gondoin, P.; Gillon, M.; Guillot, T.; Hatzes, A.; Lammer,
H.; Lanza, A. F.; Léger, A.; Llebaria, A.; Magain, P.; Mazeh, T.;
Moutou, C.; Paetzold, M.; Pinte, C.; Queloz, D.; Rauer, H.; Rouan,
D.; Schneider, J.; Wuchter, G.; Zucker, S.
2008A&A...488L..43A Altcode: 2008arXiv0807.3767A
CoRoT, the first space-based transit search, provides
ultra-high-precision light curves with continuous time-sampling over
periods of up to 5 months. This allows the detection of transiting
planets with relatively long periods, and the simultaneous study of
the host star's photometric variability. In this Letter, we report the
discovery of the transiting giant planet CoRoT-Exo-4b and use the CoRoT
light curve to perform a detailed analysis of the transit and determine
the stellar rotation period. The CoRoT light curve was pre-processed
to remove outliers and correct for orbital residuals and artefacts
due to hot pixels on the detector. After removing stellar variability
about each transit, the transit light curve was analysed to determine
the transit parameters. A discrete autocorrelation function method was
used to derive the rotation period of the star from the out-of-transit
light curve. We determine the periods of the planetary orbit and star's
rotation of 9.20205 ± 0.00037 and 8.87 ± 1.12 days respectively,
which is consistent with this being a synchronised system. We also
derive the inclination, i = 90.00_-0.085<SUP>+0.000</SUP> in degrees,
the ratio of the orbital distance to the stellar radius, a/R<SUB>s</SUB>
= 17.36<SUB>-0.25</SUB><SUP>+0.05</SUP>, and the planet-to-star radius
ratio R_p/R_s=0.1047<SUB>-0.0022</SUB><SUP>+0.0041</SUP>. We discuss
briefly the coincidence between the orbital period of the planet and the
stellar rotation period and its possible implications for the system's
migration and star-planet interaction history. <P />The CoRoT space
mission, launched on <P />December 27th 2006, has been developed and
is operated by <P />CNES, with the contribution of Austria, Belgium,
Brazil, ESA, <P />Germany, and Spain. The first CoRoT data will be
available to the <P />public in February 2009 from the CoRoT archive:
http://idoc-corot.ias.u-psud.fr/ <P />Figures 1, 4 and 5 are only
available in electronic form at http://www.aanda.org
---------------------------------------------------------
Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational
Lenses. VII. Time delays and the Hubble constant from WFI J2033-4723
Authors: Vuissoz, C.; Courbin, F.; Sluse, D.; Meylan, G.; Chantry,
V.; Eulaers, E.; Morgan, C.; Eyler, M. E.; Kochanek, C. S.; Coles,
J.; Saha, P.; Magain, P.; Falco, E. E.
2008A&A...488..481V Altcode: 2008arXiv0803.4015V
Gravitationally lensed quasars can be used to map the mass distribution
in lensing galaxies and to estimate the Hubble constant H<SUB>0</SUB>
by measuring the time delays between the quasar images. Here we report
the measurement of two independent time delays in the quadruply imaged
quasar WFI J2033-4723 (z = 1.66). Our data consist of R-band images
obtained with the Swiss 1.2 m EULER telescope located at La Silla and
with the 1.3 m SMARTS telescope located at Cerro Tololo. The light
curves have 218 independent epochs spanning 3 full years of monitoring
between March 2004 and May 2007, with a mean temporal sampling of one
observation every 4th day. We measure the time delays using three
different techniques, and we obtain Δ t<SUB>B-A</SUB> = 35.5 ±
1.4 days (3.8%) and Δ t<SUB>B-C</SUB> = 62.6<SUP>+ 4.1</SUP><SUB>-
2.3</SUB>~days ~ (<SUP>+ 6.5%</SUP><SUB>- 3.7%</SUB>), where A is a
composite of the close, merging image pair. After correcting for the
time delays, we find R-band flux ratios of F<SUB>A</SUB>/F<SUB>B</SUB>
= 2.88 ± 0.04, F<SUB>A</SUB>/F<SUB>C</SUB> = 3.38 ± 0.06, and
F<SUB>A1</SUB>/F<SUB>A2</SUB> = 1.37 ± 0.05 with no evidence for
microlensing variability over a time scale of three years. However,
these flux ratios do not agree with those measured in the quasar
emission lines, suggesting that longer term microlensing is present. Our
estimate of H<SUB>0</SUB> agrees with the concordance value:
non-parametric modeling of the lensing galaxy predicts H<SUB>0</SUB>
= 67<SUP>+13</SUP><SUB>-10</SUB> km s<SUP>-1</SUP> Mpc<SUP>-1</SUP>,
while the Single Isothermal Sphere model yields H<SUB>0</SUB> =
63<SUP>+7</SUP><SUB>-3</SUB> km s<SUP>-1</SUP> Mpc<SUP>-1</SUP>
(68% confidence level). More complex lens models using a composite
de Vaucouleurs plus NFW galaxy mass profile show twisting of the mass
isocontours in the lensing galaxy, as do the non-parametric models. As
all models also require a significant external shear, this suggests that
the lens is a member of the group of galaxies seen in field of view
of WFI J2033-4723. <P />Based on observations obtained with the 1.2 m
EULER Swiss Telescope, the 1.3 m Small and Moderate Aperture Research
Telescope System (SMARTS) which is operated by the SMARTS Consortium,
and the NASA/ESA Hubble Space Telescope as part of program HST-GO-9744
of the Space Telescope Science Institute, which is operated by the
Association of Universities for Research in Astronomy, Inc., under
NASA contract NAS 5-26555. Table 4 is only available in electronic
form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5)
or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/488/481
---------------------------------------------------------
Title: Transiting exoplanets from the CoRoT space
mission. V. CoRoT-Exo-4b: stellar and planetary parameters
Authors: Moutou, C.; Bruntt, H.; Guillot, T.; Shporer, A.; Guenther,
E.; Aigrain, S.; Almenara, J. M.; Alonso, R.; Auvergne, M.; Baglin, A.;
Barbieri, M.; Barge, P.; Benz, W.; Bordé, P.; Bouchy, F.; Deeg, H. J.;
de La Reza, R.; Deleuil, M.; Dvorak, R.; Erikson, A.; Fridlund, M.;
Gillon, M.; Gondoin, P.; Hatzes, A.; Hébrard, G.; Jorda, L.; Kabath,
P.; Lammer, H.; Léger, A.; Llebaria, A.; Loeillet, B.; Magain, P.;
Mayor, M.; Mazeh, T.; Ollivier, M.; Pätzold, M.; Pepe, F.; Pont,
F.; Queloz, D.; Rabus, M.; Rauer, H.; Rouan, D.; Schneider, J.; Udry,
S.; Wuchterl, G.
2008A&A...488L..47M Altcode: 2008arXiv0807.3739M
Aims: The CoRoT satellite has announced its fourth transiting planet
(Aigrain et al. 2008, A&A, 488, L43) with space photometry. We
describe and analyse complementary observations of this system
performed to establish the planetary nature of the transiting
body and to estimate the fundamental parameters of the planet and
its parent star. <BR />Methods: We have analysed high precision
radial-velocity data, ground-based photometry, and high signal-to-noise
ratio spectroscopy. <BR />Results: The parent star CoRoT-Exo-4 (2MASS
06484671-0040219) is a late F-type star of mass of 1.16 M<SUB>⊙</SUB>
and radius of 1.17 R<SUB>⊙</SUB>. The planet has a circular orbit with
a period of 9.20205 d. The planet radius is 1.19 R_Jup and the mass
is 0.72 M_Jup. It is a gas-giant planet with a “normal” internal
structure of mainly H and He. CoRoT-Exo-4b has the second longest period
of the known transiting planets. It is an important discovery since
it occupies an empty area in the mass-period diagram of transiting
exoplanets. <P />Based on observations obtained with CoRoT, a space
project operated by the French Space Agency, CNES, with participation
of the Science Programme of ESA, ESTEC/RSSD, Austria, Belgium, Brazil,
Germany and Spain; and on observations made with the SOPHIE spectrograph
at Observatoire de Haute Provence, France (PNP.07B.MOUT), and the HARPS
spectrograph at ESO La Silla Observatory (079.C-0127/F). <P />Table 2
and Fig. 5 are only available in electronic form at http://www.aanda.org
---------------------------------------------------------
Title: High-dispersion Spectroscopic Observations Of 8P/Tuttle
With VLT/CRIRES
Authors: Kobayashi, Hitomi; Bockelee-Morvan, D.; Dello Russo, N.;
Kawakita, H.; Verback, R. J.; Weaver, H.; Jehin, E.; Manfroid, J.;
Smette, A.; Cochran, A.; Hutsemekers, D.; Schulz, R.; Stuwe, J.;
Weiler, M.; Zucconi, J.; Arpigny, C.; Biver, N.; Crovisier, J.;
Magain, P.; Rauer, H.; Sana, H.
2008DPS....40.0504K Altcode: 2008BAAS...40..394K
We present near-infrared observations of organic molecules in comet
8P/Tuttle. <P />Comet 8P/Tuttle is a Halley-type comet and its last
perihelion was in early January 2008. Our observations were carried out
on January 28 and February 4 using CRIRES (CRyogenic high-resolution
InfraRed Echelle Spectrograph) at the Very Large Telescope (VLT). We
used a 0.2" slit which provided a spectral resolving power of 80,000. We
detected H<SUB>2</SUB>O, OH, HCN, C<SUB>2</SUB>H<SUB>2</SUB> on Jan 28,
and H<SUB>2</SUB>O, OH, CH<SUB>4</SUB>, C<SUB>2</SUB>H<SUB>6</SUB>, and
CH<SUB>3</SUB>OH on Feb 4. <P />We find that 8P/Tuttle is depleted in
HCN, C<SUB>2</SUB>H<SUB>2</SUB> and C<SUB>2</SUB>H<SUB>6</SUB> relative
to H<SUB>2</SUB>O compared with most other Oort cloud comets studied
to date. Perhaps these depletions suggest that 8P/Tuttle formed in a
different region from most Oort cloud comets, but it is also possible
that the depletions are caused by repeated passages through the inner
solar system.
---------------------------------------------------------
Title: VizieR Online Data Catalog: Time delays and H0 from WFI
J2033-4723 (Vuissoz+, 2008)
Authors: Vuissoz, C.; Courbin, F.; Sluse, D.; Meylan, G.; Chantry,
V.; Eulaers, E.; Morgan, C.; Eyler, M. E.; Kochanek, C. S.; Coles,
J.; Saha, P.; Magain, P.; Falco, E. E.
2008yCat..34880481V Altcode:
Photometry of WFI J2033-4723, as in Fig. 3 of the paper. The first
column gives the Julian date and corresponds to HJD days. The second
column is the seeing, in arcsec. Column 3-8 display the photometric
measurements of the quasar components A, B and C respectively, with
the corresponding error bars. The last column finally provides the
name of the telescope used for each measurement. <P />(1 data file).
---------------------------------------------------------
Title: Understanding the Relations between QSOs and Their Host
Galaxies from Combined HST Imaging and VLT Spectroscopy
Authors: Letawe, Y.; Magain, P.; Letawe, G.; Courbin, F.; Hutsemékers,
D.
2008ApJ...679..967L Altcode: 2008arXiv0802.1386L
The host galaxies of six nearby QSOs are studied on the basis of
high-resolution HST optical images and spatially resolved VLT slit
spectra. The gas ionization and velocity are mapped as a function
of the distance to the central QSO. In the majority of the cases,
the QSO significantly contributes to the gas ionization in its whole
host galaxy, and sometimes even outside. Reflection or scattering
of the QSO Hα line from remote regions of the galaxy is detected
in several instances. The line shifts show that, in all cases,
the matter responsible for the light reflection moves away from the
QSO, likely accelerated by its radiation pressure. The two faintest
QSOs reside in spirals, with some signs of a past gravitational
perturbation. One of the intermediate-luminosity QSOs resides in
a massive elliptical containing gas ionized (and probably pushed
away) by the QSO radiation. The other medium-power object is found
in a spiral galaxy displaying complex velocity structure, with the
central QSO moving with respect to the bulge, probably as a result of
a galactic collision. The two most powerful objects are involved in
violent gravitational interactions, and one of them has no detected
host. These results suggest that (1) large-scale phenomena, such as
galactic collisions, are closely related to the triggering and the
feeding of the QSO and (2) once ignited, the QSO has significant
influence on its large-scale neighborhood (often the whole host and
sometimes further away). <P />Based on observations made with the
Nasa/ESA Hubble Space Telescope (Cycle 13 proposal 10238), and with
ANTU/UT1 at ESO-Paranal observatory in Chile [programs 65.P-0361(A)
and 66.B-0139(A)].
---------------------------------------------------------
Title: Transiting exoplanets from the CoRoT space
mission. II. CoRoT-Exo-2b: a transiting planet around an active G star
Authors: Alonso, R.; Auvergne, M.; Baglin, A.; Ollivier, M.; Moutou,
C.; Rouan, D.; Deeg, H. J.; Aigrain, S.; Almenara, J. M.; Barbieri, M.;
Barge, P.; Benz, W.; Bordé, P.; Bouchy, F.; de La Reza, R.; Deleuil,
M.; Dvorak, R.; Erikson, A.; Fridlund, M.; Gillon, M.; Gondoin, P.;
Guillot, T.; Hatzes, A.; Hébrard, G.; Kabath, P.; Jorda, L.; Lammer,
H.; Léger, A.; Llebaria, A.; Loeillet, B.; Magain, P.; Mayor, M.;
Mazeh, T.; Pätzold, M.; Pepe, F.; Pont, F.; Queloz, D.; Rauer, H.;
Shporer, A.; Schneider, J.; Stecklum, B.; Udry, S.; Wuchterl, G.
2008A&A...482L..21A Altcode: 2008arXiv0803.3207A
Context: The CoRoT mission, a pioneer in exoplanet searches from
space, has completed its first 150 days of continuous observations
of ~12 000 stars in the galactic plane. An analysis of the raw data
identifies the most promising candidates and triggers the ground-based
follow-up. <BR />Aims: We report on the discovery of the transiting
planet CoRoT-Exo-2b, with a period of 1.743 days, and characterize its
main parameters. <BR />Methods: We filter the CoRoT raw light curve
of cosmic impacts, orbital residuals, and low frequency signals from
the star. The folded light curve of 78 transits is fitted to a model
to obtain the main parameters. Radial velocity data obtained with the
SOPHIE, CORALIE and HARPS spectrographs are combined to characterize
the system. The 2.5 min binned phase-folded light curve is affected by
the effect of sucessive occultations of stellar active regions by the
planet, and the dispersion in the out of transit part reaches a level
of 1.09×10<SUP>-4</SUP> in flux units. <BR />Results: We derive a
radius for the planet of 1.465 ± 0.029 R_Jup and a mass of 3.31 ±
0.16 M_Jup, corresponding to a density of 1.31 ± 0.04 g/cm^3. The
large radius of CoRoT-Exo-2b cannot be explained by current models of
evolution of irradiated planets. <P />Based on observations obtained
with CoRoT, a space project operated by the French Space Agency, CNES,
with participation of the Science Programme of ESA, ESTEC/RSSD, Austria,
Belgium, Brazil, Germany and Spain; and on observations made with
SOPHIE spectrograph at Observatoire de Haute Provence, France (PNP.07
A.MOUT), CORALIE, and HARPS spectrograph at ESO La Silla Observatroy
(079.C-0127/F)). <P />Table 2 is only available in electronic form
at http://www.aanda.org
---------------------------------------------------------
Title: Transiting exoplanets from the CoRoT space
mission. I. CoRoT-Exo-1b: a low-density short-period planet around
a G0V star
Authors: Barge, P.; Baglin, A.; Auvergne, M.; Rauer, H.; Léger,
A.; Schneider, J.; Pont, F.; Aigrain, S.; Almenara, J. -M.; Alonso,
R.; Barbieri, M.; Bordé, P.; Bouchy, F.; Deeg, H. J.; La Reza,
De; Deleuil, M.; Dvorak, R.; Erikson, A.; Fridlund, M.; Gillon, M.;
Gondoin, P.; Guillot, T.; Hatzes, A.; Hebrard, G.; Jorda, L.; Kabath,
P.; Lammer, H.; Llebaria, A.; Loeillet, B.; Magain, P.; Mazeh, T.;
Moutou, C.; Ollivier, M.; Pätzold, M.; Queloz, D.; Rouan, D.; Shporer,
A.; Wuchterl, G.
2008A&A...482L..17B Altcode: 2008arXiv0803.3202B
Context: The pioneer space mission for photometric planet searches,
CoRoT, steadily monitors about 12 000 stars in each of its fields of
view. Transit candidates can be detected early in the processing of the
data and before the end of a run of observation. <BR />Aims: We report
the detection of the first planet discovered by CoRoT and characterizing
it with the help of follow-up observations. <BR />Methods: Raw data
were filtered from outliers and residuals at the orbital period of
the satellite. The orbital parameters and the radius of the planet
were estimated by best fitting the phase folded light curve with 34
successive transits. Doppler measurements with the SOPHIE spectrograph
permitted us to secure the detection against binaries and to estimate
the mass of the planet. <BR />Results: The accuracy of the data is
very high with a dispersion in the 2.17 min binned phase-folded light
curve that does not exceed ~3.×10<SUP>-4</SUP> in flux unit. The
planet orbits a mildly metal-poor G0V star of magnitude V=13.6 in
1.5 days. The estimated mass and radius of the star are 0.95±0.15
M<SUB>⊙</SUB> and 1.11±0.05 R<SUB>⊙</SUB>. We find the planet
has a radius of 1.49±0.08 R_Jup, a mass of 1.03±0.12 M_Jup, and
a particularly low mean density of 0.38±0.05 g cm<SUP>-3</SUP>. <P
/>The CoRoT space mission, launched on Dec. 27th, 2006, was developed
and is operated by the CNES, with participation of the Science
Program of ESA, ESTEC/RSSD, Austria, Belgium, Brazil, Germany and
Spain. Based in part on observations with the SOPHIE spectrograph
at Obs. de Haute Provence, France. Table [see full text] is only
available in electronic form at http://www.aanda.org Individual
photometric measurements are only available in electronic form at
the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or
via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/482/L17
---------------------------------------------------------
Title: Transiting exoplanets from the CoRoT space mission. III. The
spectroscopic transit of CoRoT-Exo-2b with SOPHIE and HARPS
Authors: Bouchy, F.; Queloz, D.; Deleuil, M.; Loeillet, B.; Hatzes,
A. P.; Aigrain, S.; Alonso, R.; Auvergne, M.; Baglin, A.; Barge, P.;
Benz, W.; Bordé, P.; Deeg, H. J.; de La Reza, R.; Dvorak, R.; Erikson,
A.; Fridlund, M.; Gondoin, P.; Guillot, T.; Hébrard, G.; Jorda, L.;
Lammer, H.; Léger, A.; Llebaria, A.; Magain, P.; Mayor, M.; Moutou,
C.; Ollivier, M.; Pätzold, M.; Pepe, F.; Pont, F.; Rauer, H.; Rouan,
D.; Schneider, J.; Triaud, A. H. M. J.; Udry, S.; Wuchterl, G.
2008A&A...482L..25B Altcode: 2008arXiv0803.3209B
We report on the spectroscopic transit of the massive hot-Jupiter
CoRoT-Exo-2b observed with the high-precision spectrographs SOPHIE
and HARPS. By modeling the radial velocity anomaly occurring during
the transit due to the Rossiter-McLaughlin (RM) effect, we determine
the sky-projected angle between the stellar spin and the planetary
orbital axis to be close to zero λ = 7.2 ± 4.5 deg, and we secure
the planetary nature of CoRoT-Exo-2b. We discuss the influence of
the stellar activity on the RM modeling. Spectral analysis of the
parent star from HARPS spectra are presented. <P />Observations made
with SOPHIE spectrograph at Observatoire de Haute Provence, France
(PNP.07A.MOUT) and HARPS spectrograph at ESO La Silla Observatory
(079.C-0127(F)). The CoRoT space mission, launched on December 27th
2006, has been developed and is operated by CNES, with the contribution
of Austria, Belgium, Brasil, ESA, Germany, and Spain.
---------------------------------------------------------
Title: Quasar Host Orientation and Polarization: Insights into the
Type 1/Type 2 Dichotomy
Authors: Borguet, B.; Hutsemékers, D.; Letawe, G.; Letawe, Y.;
Magain, P.
2008RMxAC..32..167B Altcode: 2007arXiv0710.4072B
We investigate correlations between the optical linear polarization
position angle and the orientation of the host galaxy/extended
emission of Type 1 and Type 2 Radio-Loud (RL) and Radio-Quiet (RQ)
quasars. We have used high resolution Hubble Space Telescope (HST)
data and deconvolution process to obtain a good determination of the
host galaxy orientation. With these new measurements and a compilation
of data from the literature, we find a significant correlation between
the polarization position angle and the position angle of the major
axis of the host galaxy/extended emission. The correlation appears
different for Type 1 and Type 2 objects and depends on the redshift
of the source. Interpretations in the framework of the unification
model are discussed.
---------------------------------------------------------
Title: VizieR Online Data Catalog: CoRoT space mission. I. (Barge+,
2008)
Authors: Barge, P.; Baglin, A.; Auvergne, M.; Rauer, H.; Leger, A.;
Schneider, J.; Pont, F.; Aigrain, S.; Almenara, J. -M.; Alonso, R.;
Barbieri, M.; Borde, P.; Bouchy, F.; Deeg, H. J.; de La, R. Reza;
Deleuil, M.; Dvorak, R.; Erikson, A.; Fridlund, M.; Gillon, M.;
Gondoin, P.; Guillot, T.; Hatzes, A.; Hebrard, G.; Jorda, L.; Kabath,
P.; Lammer, H.; Llebaria, A.; Loeillet, B.; Magain, P.; Mazeh,
T.; Moutou, C.; Ollivier, M.; Patzold, M.; Queloz, D.; Rouan, D.;
Shporer, A.
2008yCat..34829017B Altcode:
Raw data were filtered from outliers and residuals at the orbital period
of the satellite. The orbital parameters and the radius of the planet
were estimated by best fitting the phase folded light curve with 34
successive transits. Doppler measurements with the SOPHIE spectrograph
permitted us to secure the detection against binaries and to estimate
the mass of the planet. <P />The individual photometric measurements
will be available after the proprietary period of the CoRoT project. See
http://smsc.cnes.fr/COROT for more information
---------------------------------------------------------
Title: Slit and integral-field optical spectroscopy of the enigmatic
quasar HE 0450-2958
Authors: Letawe, G.; Magain, P.; Courbin, F.
2008A&A...480...69L Altcode: 2007arXiv0709.3743L
Context: Interest in the quasar HE 0450-2958 arose following the
publication of the non-detection of its expected massive host, leading
to various interpretations. <BR />Aims: This article investigates the
gaseous and stellar contents of the system through additional VLT/FORS
slit spectra and integral field spectroscopy from VLT/VIMOS. <BR
/>Methods: We apply our MCS deconvolution algorithm on slit spectra
for the separation of the QSO and diffuse components, and develop a new
method to remove the point sources in Integral Field Spectra, allowing
extraction of velocity maps, narrow-line images, spatially resolved
spectra or ionization diagrams of the surroundings of HE 0450-2958. <BR
/>Results: The whole system is embedded in gas, mostly ionized by
the QSO radiation field and shocks associated with radio jets. The
observed gas and star dynamics are unrelated, revealing a strongly
perturbed system. Despite longer spectroscopic observations, the host
galaxy remains undetected. <P />Based on observations made with VLT/UT1
(program 76.B-0693(B)), and with the VLT/UT3 (program 72.B-0268(B))
at ESO-Paranal observatory in Chile, in addition with NASA/ESA Hubble
Space Telescope observations from Cycle 13, proposal #10238.
---------------------------------------------------------
Title: Evidence of a type 1/type 2 dichotomy in the correlation
between quasar optical polarization and host-galaxy/extended emission
position angles
Authors: Borguet, B.; Hutsemékers, D.; Letawe, G.; Letawe, Y.;
Magain, P.
2008A&A...478..321B Altcode: 2007arXiv0710.4048B
Aims:For Seyfert galaxies, the AGN unification model provides a simple
and well-established explanation of the type 1/type 2 dichotomy through
orientation-based effects. The generalization of this unification
model to the higher luminosity AGNs that quasars are remains a key
question. The recent detection of type 2 radio-quiet quasars seems
to support such an extension. We propose a further test of this
scenario. <BR />Methods: On the basis of a compilation of quasar
host-galaxy position angles consisting of previously published data and
of new measurements performed using HST Archive images, we investigate
the possible existence of a correlation between the linear polarization
position angle and the host-galaxy/extended emission position angle of
quasars. <BR />Results: We find that the orientation of the rest-frame
UV/blue extended emission is correlated to the direction of the
quasar polarization. For type 1 quasars, the polarization is aligned
with the extended UV/blue emission, while these two quantities are
perpendicular in type 2 objects. This result is independent of the
quasar radio loudness. We interpret this (anti-)alignment effect in
terms of scattering in a two-component polar+equatorial model that
applies to both type 1 and type 2 objects. Moreover, the orientation
of the polarization -and then of the UV/blue scattered light- does
not appear correlated to the major axis of the stellar component of
the host-galaxy measured from near-IR images.
---------------------------------------------------------
Title: Study of the QSO HE0354-5500 with combined HST imaging and
VLT spectroscopy . An example of a deconvolution-based method for
probing the QSOs host galaxies characteristics
Authors: Letawe, Y.; Magain, P.; Letawe, G.; Courbin, F.; Hutsemékers,
D.
2008MmSAI..79.1251L Altcode:
The host galaxy of the QSO HE0354-5500 (M_B=-24.7, z=0.2674)
is studied on the basis of high resolution HST optical images and
spatially resolved VLT slit spectra. The morphology and dynamics of
the host are described. The gas ionization and velocity are mapped
as a function of the distance to the central QSO. Reflection or
scattering of the QSO Halpha line from remote regions of the galaxy
is detected. The line shifts show that the matter responsible for the
light reflection moves away from the QSO, likely accelerated by its
radiation pressure. Moreover, different resolved emission regions are
found in the central kpc, both in the images and the spectra.
---------------------------------------------------------
Title: A Multi-Wavelength Simultaneous Study of the Composition of
the Halley-Family Comet 8P/Tuttle at the VLT
Authors: Bockelée-Morvan, D.; Dello Russo, N.; Jehin, E.; Manfroid,
J.; Smette, A.; Cochran, A.; Hutsemékers, D.; Kawakita, H.; Kobayashi,
H.; Schulz, R.; Weiler, M.; Zucconi, J. M.; Arpigny, C.; Biver,
N.; Crovisier, J.; Magain, P.; Rauer, H.; Sana, H.; Vervack, R. J.;
Weaver, H.
2008LPICo1405.8190B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: VizieR Online Data Catalog: QSO Type1/Type2 dichotomy
(Borguet+, 2008)
Authors: Borguet, B.; Hutsemekers, D.; Letawe, G.; Letawe, Y.;
Magain, P.
2007yCat..34780321B Altcode:
This table contains the measurements/compilation of host galaxy/
extended emission position angle in the visible and near-IR domain,
polarimetric data, and radio axis orientation for the 135 quasars of
our sample. The angles are given in degrees east of north. The table
gives the spectral and the radio-loud/radio-quiet classification of
each object according to the references. <P />(2 data files).
---------------------------------------------------------
Title: Deconvolution of HST images of the Cloverleaf gravitational
lens. Detection of the lensing galaxy and a partial Einstein ring
Authors: Chantry, V.; Magain, P.
2007A&A...470..467C Altcode: 2006astro.ph.12094C
Archival HST/NICMOS-2 images of the Cloverleaf gravitational lens
(H1413+117), a quadruply-imaged quasar, were analysed with a new method
derived from the MCS deconvolution algorithm (Magain et al. 1998). This
method is based on an iterative process which simultaneously allows
us to determine the Point Spread Function (PSF) and to perform
a deconvolution of images containing several point sources plus
extended structures. As such, it is well-adapted to the processing of
gravitational lens images, especially in the case of multiply-imaged
quasars. Two sets of data were analysed: the first one, which was
obtained through the F160W filter in 1997, basically corresponds to a
continuum image, while the second one, obtained through the narrower
F180M filter in 2003, is centered around the forbidden [Oiii] emission
lines at the source redshift, thus probing the narrow-line region of the
quasar. The deconvolution gives astrometric and photometric measurements
in both filters and reveals the primary lensing galaxy as well as a
partial Einstein ring. The high accuracy of the results is particularly
important in order to model the lensing system and to reconstruct the
source undergoing the strong lensing. The reliability of the method
is checked on a synthetic image similar to H1413+117. <P />Based
on observations made with the NASA/ESA HST Hubble Space Telescope,
obtained from the data archive at the Space Science Institute. STScI
is operated by AURA, the Association of Universities for Research in
Astronomy, Inc., under NASA contract NAS-5-26555.
---------------------------------------------------------
Title: DECPHOT: An Optimal Deconvolution-based Photometric Reduction
Method
Authors: Gillon, M.; Magain, P.; Chantry, V.; Letawe, G.; Sohy, S.;
Courbin, F.; Pont, F.; Moutou, C.
2007ASPC..366..113G Altcode: 2007astro.ph..1607G
A high accuracy photometric reduction method is needed to take full
advantage of the potential of the transit method for the detection and
characterization of exoplanets, especially in deep crowded fields. In
this context, we present DECPHOT, a new deconvolution-based photometry
algorithm able to deal with a very high level of crowding and large
variations of seeing. It also increases the resolution of astronomical
images, an important advantage for the discrimination of false positives
in transit photometry.
---------------------------------------------------------
Title: On the Influence of Blends on the Potential of Ground-based
Transit Surveys
Authors: Gillon, M.; Magain, P.
2007ASPC..366..283G Altcode: 2007astro.ph..1609G
Transit surveys have to observe many stars all at once in order
to compensate for the rarity of the searched events. Such surveys,
especially the ones observing a deep field of view and/or broadening
their stellar images, have to deal with a relatively high level of
crowding. This crowding could lead to a reduction of the number of
detectable transits, and the estimation of the potential of such
surveys without taking into account the influence of blends could
give overoptimistic results. We have developed a code which allows to
estimate the extent by which such a survey is affected by the crowding
of the field of view. Our results show that the influence of blends
is important only for severe levels of crowding and is in general much
less crucial than the influence of red noise.
---------------------------------------------------------
Title: On-axis spectroscopy of the host galaxies of 20 optically
luminous quasars at z ~ 0.3
Authors: Letawe, G.; Magain, P.; Courbin, F.; Jablonka, P.; Jahnke,
K.; Meylan, G.; Wisotzki, L.
2007MNRAS.378...83L Altcode: 2007MNRAS.tmp..450L; 2006astro.ph..5288L
We present the analysis of a sample of 20 bright low-redshift quasars
(M<SUB>B</SUB> < -23 and z < 0.35) observed spectroscopically
with the Very Large Telescope (VLT). The Focal Reducer/low dispersion
Spectrograph (FORS1) spectra, obtained in Multi-Object Spectroscopy
(MOS) mode, allow to observe simultaneously the quasars and several
reference stars used to spatially deconvolve the data. Applying the
Magain, Courbin & Sohy (MCS) deconvolution method, we are able to
separate the individual spectra of the quasar and of the underlying
host galaxy. Contrary to some previous claims, we find that luminous
quasars are not exclusively hosted by massive ellipticals. Most quasar
host galaxies harbour large amounts of gas, irrespective of their
morphological type. Moreover, the stellar content of half of the hosts
is a young Sc-like population, associated with a rather low-metallicity
interstellar medium. A significant fraction of the galaxies contain
gas ionized at large distances by the quasar radiation. This large
distance ionization is always associated with signs of gravitational
interactions (as detected from images or disturbed rotation curves). The
spectra of the quasars themselves provide evidence that gravitational
interactions bring dust and gas in the immediate surrounding of the
super massive black hole, allowing to feed it. The quasar activity
might thus be triggered (1) in young gas-rich spiral galaxies by local
events and (2) in more evolved galaxies by gravitational interactions
or collisions. The latter mechanism gives rises to the most powerful
quasars. Finally, we derive mass models for the isolated spiral
host galaxies and we show that the most reliable estimators of the
systemic redshift in the quasar spectrum are the tips of the Hα
and Hβ lines. <P />Based on observations made with the European
Southern Observatory (ESO) Very Large Telescope Unit 1 (ANTU/UT1)
at ESO Paranal Observatory, Chile, under program IDs 65.P-0361 and
66.B-0139. <P />E-mail: gletawe@ulg.ac.be
---------------------------------------------------------
Title: The transiting planet OGLE-TR-132b revisited with new
spectroscopy and deconvolution photometry<SUP>, </SUP>
Authors: Gillon, M.; Pont, F.; Moutou, C.; Santos, N. C.; Bouchy, F.;
Hartman, J. D.; Mayor, M.; Melo, C.; Queloz, D.; Udry, S.; Magain, P.
2007A&A...466..743G Altcode: 2007astro.ph..2192G
OGLE-TR-132b transits a very metal-rich F dwarf about 2000 pc from
the Sun, in the Galactic disc towards Carina. It orbits very close
to its host star (a = 0.03 AU) and has an equilibrium temperature
of nearly 2000 K. Using rapid-cadence transit photometry from the
FORS2 camera on the VLT and SUSI2 on the NTT, and high-resolution
spectroscopy with UVES on the VLT, we refine the shape of the transit
light curve and the parameters of the system. In particular, we
improve the planetary radius estimate, R = 1.18 ± 0.07 R<SUB>J</SUB>
and provide very precise ephemeris, T_tr = 2 453 142.59123 ± 0.0003
BJD and P = 1.689868 ± 0.000003 days. The obtained planetary mass is
1.14 ± 0.12 M_J. Our results give a slightly smaller and lighter star,
and bigger planet, than previous values. As the VLT/FORS2 light curve
obtained in this analysis with the deconvolution photometry algorithm
DECPHOT shows a transit depth in disagreement with the one obtained
by a previous study using the same data, we analyze them with two
other reduction methods (aperture and image subtraction). The light
curves obtained with the three methods are in good agreement, though
deconvolution-based photometry is significantly more precise. It
appears from these results that the smaller transit depth obtained in
the previous study was due to a normalisation problem inherent to the
reduction procedure used. <P />Based on data collected with the FORS2
imager at the VLT-UT4 telescope (Paranal Observatory, ESO, Chile) in
the programme 273.C-5017A, with the SUSI2 imager at the NTT telescope
(La Silla Observatory, ESO, Chile) in the programme 075.C-0462A,
and with the UVES spectrograph at the VLT-UT2 telescope (Paranal
Observatory, ESO, Chile) in the programme 076.C-0131. The reduced
photometric data used in this work are available only in electronic
form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5)
or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/466/743
---------------------------------------------------------
Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational
Lenses. V. The time delay in SDSS J1650+4251
Authors: Vuissoz, C.; Courbin, F.; Sluse, D.; Meylan, G.; Ibrahimov,
M.; Asfandiyarov, I.; Stoops, E.; Eigenbrod, A.; Le Guillou, L.;
van Winckel, H.; Magain, P.
2007A&A...464..845V Altcode: 2006astro.ph..6317V
Aims:Our aim is to measure the time delay between the two
gravitationally lensed images of the z_qso = 1.547 quasar SDSS
J1650+4251, in order to estimate the Hubble constant H_0. <BR
/>Methods: Our measurement is based on R-band light curves with 57
epochs obtained at Maidanak Observatory, in Uzbekistan, from May 2004
to September 2005. The photometry is performed using simultaneous
deconvolution of the data, which provides the individual light curves
of the otherwise blended quasar images. The time delay is determined
from the light curves using two very different numerical techniques,
i.e., polynomial fitting and direct cross-correlation. The time delay
is converted into H<SUB>0</SUB> following analytical modeling of the
potential well. <BR />Results: Our best estimate of the time delay is
Δ t = 49.5 ± 1.9 days, i.e., we reach a 3.8% accuracy. The R-band
flux ratio between the quasar images, corrected for the time delay
and for slow microlensing, is F_A/F<SUB>B</SUB> = 6.2 ± 5%. <BR
/>Conclusions: .The accuracy reached on the time delay allows us
to discriminate well between families of lens models. As for most
other multiply imaged quasars, only models of the lensing galaxy
that have a de Vaucouleurs mass profile plus external shear give
a Hubble constant compatible with the current most popular value
(H<SUB>0</SUB> = 72 ± 8 km s<SUP>-1</SUP> Mpc<SUP>-1</SUP>). A more
realistic singular isothermal sphere model plus external shear gives
H<SUB>0</SUB> = 51.7<SUP>+4.0</SUP><SUB>-3.0</SUB> km s<SUP>-1</SUP>
Mpc<SUP>-1</SUP>. <P />Table [see full text] is only available in
electronic form at http://www.aanda.org
---------------------------------------------------------
Title: VizieR Online Data Catalog: Transiting planet OGLE-TR-132b
(Gillon+, 2007)
Authors: Gillon, M.; Pont, F.; Moutou, C.; Santos, C. N.; Bouchy, F.;
Hartman, D. J.; Mayor, M.; Melo, C.; Queloz, D.; Udry, S.; Magain, P.
2007yCat..34660743G Altcode:
We present high-precision photometric coverage of two transits of the
planet OGLE-TR-132b. These data have been obtained with the FORS2 camera
on the VLT and the SUSI2 on the NTT. Both transits have been observed
in the R filter. The deconvolution-based method DECPHOT (Gillon et
al., 2006A&A...459..249G, Magain et al., 2007A&A...461..373M,
Gillon et al., 2007, in prep.) was used to reduce the data. <P />(2
data files).
---------------------------------------------------------
Title: A deconvolution-based algorithm for crowded field photometry
with unknown point spread function
Authors: Magain, P.; Courbin, F.; Gillon, M.; Sohy, S.; Letawe, G.;
Chantry, V.; Letawe, Y.
2007A&A...461..373M Altcode: 2006astro.ph..9600M
A new method is presented for determining the point <P />spread function
(PSF) of images that lack bright and isolated <P />stars. It is based on
the same principles as the MCS image <P />deconvolution algorithm. It
uses the <P />information contained in all stellar images to achieve
<P />the double task of reconstructing the PSFs for single or multiple
<P />exposures of the same field and to extract the photometry of
<P />all point sources in the field of view. The use of the full <P
/>information available allows us to construct an accurate PSF. The <P
/>possibility to simultaneously consider several exposures makes it <P
/>well suited to the measurement of the <P />light curves of blended
point sources from data that would be <P />very difficult or even
impossible to analyse with traditional PSF <P />fitting techniques. <P
/>The potential of the method for the <P />analysis of ground-based and
space-based data is tested on <P />artificial images and illustrated by
several examples, including <P />HST/NICMOS images of a lensed quasar
and VLT/ISAAC images of <P />a faint blended Mira star in the halo of
the giant elliptical <P />galaxy NGC 5128 (Cen A).
---------------------------------------------------------
Title: High accuracy transit photometry of the planet OGLE-TR-113b
with a new deconvolution-based method
Authors: Gillon, M.; Pont, F.; Moutou, C.; Bouchy, F.; Courbin, F.;
Sohy, S.; Magain, P.
2006A&A...459..249G Altcode: 2006astro.ph..6395G
A high accuracy photometry algorithm is needed to take full advantage
of the potential of the transit method for the characterization of
exoplanets, especially in deep crowded fields. It has to reduce to the
lowest possible level the negative influence of systematic effects
on the photometric accuracy. It should also be able to cope with a
high level of crowding and with large-scale variations of the spatial
resolution from one image to another. A recent deconvolution-based
photometry algorithm fulfills all these requirements, and it also
increases the resolution of astronomical images, which is an important
advantage for the detection of blends and the discrimination of
false positives in transit photometry. We made some changes to this
algorithm <P />to optimize it for transit photometry and used it to
reduce NTT/SUSI2 observations of two transits of OGLE-TR-113b. This
reduction has led to two very high precision transit light curves
with a low level of systematic residuals, used together with former
photometric and spectroscopic measurements to derive new stellar and
planetary parameters in excellent agreement with previous ones, but
significantly more precise.
---------------------------------------------------------
Title: VLT on-axis spectroscopy of quasar host galaxies
Authors: Letawe, G.; Magain, P.; Courbin, F.; Jablonka, P.; Meylan,
G.; Jahnke, K.; Wisotzki, L.
2006NewAR..50..779L Altcode:
We present the full analysis of our sample of 20 bright low
redshift quasars (M<SUB>B</SUB> < -23 and z < 0.35),
observed spectroscopically with the VLT FORS1, with objectives of
characterizing the hosts and trying to understand how quasars are
fueled or triggered. Applying the MCS deconvolution method, we are
able to separate the galactic light from the quasar light, enabling
i.e. global analysis of the gaseous and stellar content and gaseous
dynamics. We find that 45% of the sample show signs of interaction,
while half of the quasars are hosted in spiral galaxies, even when
brighter than M<SUB>V</SUB> = -23.5. We also find many galaxies
containing gas ionized by the quasar radiation far from the nucleus,
all of these showing interaction or merger signs. We find spectroscopic
evidences that such interactions bring gas in the broad and narrow
line regions and power the nucleus.
---------------------------------------------------------
Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational
Lenses. II. SDSS J0924+0219: the redshift of the lensing galaxy,
the quasar spectral variability and the Einstein rings
Authors: Eigenbrod, A.; Courbin, F.; Dye, S.; Meylan, G.; Sluse, D.;
Vuissoz, C.; Magain, P.
2006A&A...451..747E Altcode: 2005astro.ph.10641E
Aims.To provide the observational constraints required to use the
gravitationally lensed quasar SDSS J0924+0219 for the determination
of H<SUB>0</SUB> from the time delay method. We measure here the
redshift of the lensing galaxy, we show the spectral variability of
the source, and we resolve the lensed host galaxy of the source. <BR
/>Methods.We present our VLT/FORS1 deep spectroscopic observations
of the lensed quasar SDSS J0924+0219, as well as archival HST/NICMOS
and ACS images of the same object. The two-epoch spectra, obtained in
the Multi Object Spectroscopy (MOS) mode, allow for very accurate flux
calibration and spatial deconvolution. This strategy provides spectra
for the lensing galaxy and for the quasar images A and B, free of any
mutual light contamination. We deconvolve the HST images as well,
which reveal a double Einstein ring. The mass distributions in the
lens, reconstructed in several ways, are compared. <BR />Results.We
determine the redshift of the lensing galaxy in SDSS J0924+0219:
z_lens = 0.394±0.001. Only slight spectral variability is seen in
the continuum of quasar images A and B, while the C III] , Mg II and
Fe II emission lines display obvious changes. The flux ratio between
the quasar images A and B is the same in the emission lines and in
the continuum. One of the Einstein rings found using deconvolution
corresponds to the lensed quasar host galaxy at z=1.524 and a second
bluer one, is the image either of a star-forming region in the
host galaxy, or of another unrelated lower redshift object. A broad
range of lens models give a satisfactory fit to the data. However,
they predict very different time delays, making SDSS J0924+0219 an
object of particular interest for photometric monitoring. In addition,
the lens models reconstructed using exclusively the constraints from
the Einstein rings, or using exclusively the astrometry of the quasar
images, are not compatible. This suggests that multipole-like structures
play an important role in SDSS J0924+0219. <BR />
---------------------------------------------------------
Title: The Host Galaxies of the Brightest Quasars: Gas-Rich Galaxies,
Mergers, and Young Stars
Authors: Courbin, Frédéric; Letawe, Géraldine; Meylan, Georges;
Magain, Pierre; Jablonka, Pascale; Jahnke, Knud; Wisotzki, Lutz;
Letawe, Yannick; North, Pierre
2006Msngr.124...32C Altcode:
Because they are faint and hidden in the glare of a much
brighter unresolved source, quasar host galaxies still challenge
the most powerful telescopes, instrumentation and processing
techniques. Determining their basic morphological parameters and
their integrated colours is feasible, but difficult, from imaging
alone. However, detailed information on their stellar and gas contents
and on their dynamics is achievable with deep spectroscopy.
---------------------------------------------------------
Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational
Lenses. III. Redshift of the lensing galaxy in eight gravitationally
lensed quasars
Authors: Eigenbrod, A.; Courbin, F.; Meylan, G.; Vuissoz, C.;
Magain, P.
2006A&A...451..759E Altcode: 2005astro.ph.11026E
Aims.We measure the redshift of the lensing galaxy in eight
gravitationally lensed quasars in view of determining the Hubble
parameter H0 from the time delay method. <BR />Methods.Deep VLT/FORS1
spectra of lensed quasars are spatially deconvolved in order to
separate the spectrum of the lensing galaxies from the glare of the
much brighter quasar images. A new observing strategy is devised. It
involves observations in Multi-Object-Spectroscopy (MOS) which allows
the simultaneous observation of the target and of several PSF and
flux calibration stars. The advantage of this method over traditional
long-slit observations is a much more reliable extraction and flux
calibration of the spectra. <BR />Results.For the first time we measure
the redshift of the lensing galaxy in three multiply-imaged quasars:
SDSS J1138+0314 (z_lens = 0.445), SDSS J1226-0006 (z_lens = 0.517),
SDSS J1335+0118 (z_lens = 0.440), and we give a tentative estimate of
the redshift of the lensing galaxy in Q 1355-2257 (z_lens = 0.701). We
confirm four previously measured redshifts: HE 0047-1756 (z_lens =
0.407), HE 0230-2130 (z_lens = 0.523), HE 0435-1223 (z_lens = 0.454)
and WFI J2033-4723 (z_lens = 0.661). In addition, we determine the
redshift of the second lensing galaxy in HE 0230-2130 (z_lens =
0.526). The spectra of all lens galaxies are typical for early-type
galaxies, except for the second lensing galaxy in HE 0230-2130 which
displays prominent [OII] emission. <BR />
---------------------------------------------------------
Title: High precision determination of the atmospheric parameters
and abundances of the COROT main targets
Authors: Gillon, M.; Magain, P.
2006A&A...448..341G Altcode: 2005astro.ph.11099G
Context: .One of the main goals of the COROT mission is to get precise
photometric observations of selected bright stars in order to allow
the modelling of their interior through asteroseismology. However,
in order to interpret the asteroseismological data, the effective
temperature, surface gravity, and chemical composition of the stars
must be known with sufficient accuracy.Aims.To carry out this task,
we have developed a spectroscopic method called APASS (Atmospheric
Parameters and Abundances from Synthetic Spectra) which allows precise
analysis of stars with a moderate to high rotational velocity,
which is the case for most primary COROT targets.Methods.Our
method is based on synthetic spectra in which individual lines
are replaced by analysis units (isolated lines or line blends,
depending on the crowding of the spectral region and on the rotational
broadening). It works differentially with respect to the Sun and allows
the atmospheric parameters and chemical abundances to be determined
by considering analysis units with different sensitivities to these
various parameters.Results.Using high signal-to-noise spectra and the
APASS method, we determined the atmospheric parameters and chemical
abundances of 13 primary COROT targets. Our results agree well with
those obtained by Bruntt using his software VWA and with those obtained
with the software TEMPLOGG. However, in both cases, our error bars
are significantly smaller than those of other methods. Our effective
temperatures are also in excellent agreement with those obtained
with the IR photometry method. For five stars with relatively low
rotational velocity, we also performed an analysis with a classical
equivalent-width method to test agreement with APASS results. We show
that equivalent-width measurements by Gaussian or Voigt profile-fitting
are sensitive to the rotational broadening, leading to systematic errors
whenever the projected rotation velocity is non-negligible. The APASS
method appears superior in all cases and should thus be preferred.
---------------------------------------------------------
Title: On the potential of extrasolar planet transit surveys
Authors: Gillon, M.; Courbin, F.; Magain, P.; Borguet, B.
2005A&A...442..731G Altcode: 2005astro.ph..8109G
We analyse the respective benefits and drawbacks of ground-based
and space-based transit surveys for extrasolar planets. Based on
simple but realistic assumptions about the fraction of lower main
sequence stars harboring telluric and giant planets within the outer
limit of the habitable zone, we predict the harvests of fictitious
surveys with three existing wide field optical and near-IR cameras:
the CFHT-Megacam, SUBARU-Suprime and VISTA-IR. An additional promising
instrument is considered, VISTA-Vis, currently under development. The
results are compared with the harvests predicted under exactly the same
assumptions, for the space missions COROT and KEPLER. We show that
ground-based wide field surveys may discover more giant planets than
space missions. However, space surveys seem to constitute the best
strategy to search for telluric planets. In this respect, the KEPLER
mission appears 50 times more efficient than any of the ground-based
surveys considered here. KEPLER might even discover telluric planets
in the habitable zone of their host star.
---------------------------------------------------------
Title: Photometric monitoring of the doubly imaged quasar UM 673:
possible evidence for chromatic microlensing
Authors: Nakos, Th.; Courbin, F.; Poels, J.; Libbrecht, C.; Magain,
P.; Surdej, J.; Manfroid, J.; Burud, I.; Hjorth, J.; Germany, L.;
Lidman, C.; Meylan, G.; Pompei, E.; Pritchard, J.; Saviane, I.
2005A&A...441..443N Altcode: 2005astro.ph..7164N
We present the results of two-band CCD photometric monitoring of the
gravitationally lensed quasar Q 0142-100 (UM 673). The data, obtained
at ESO-La Silla with the 1.54 m Danish telescope in the Gunn i-band
(October 1998-September 1999) and in the Johnson V-band (October 1998
to December 2001), were analyzed using three different photometric
methods. The light-curves obtained with all methods show variations,
with a peak-to-peak amplitude of 0.14 mag in V. Although it was not
possible to measure the time delay between the two lensed QSO images,
the brighter component displays possible evidence for microlensing:
it becomes bluer as it gets brighter, as expected under the assumption
of differential magnification of a quasar accretion disk.
---------------------------------------------------------
Title: Chemical abundances in 43 metal-poor stars
Authors: Jonsell, K.; Edvardsson, B.; Gustafsson, B.; Magain, P.;
Nissen, P. E.; Asplund, M.
2005A&A...440..321J Altcode: 2005astro.ph..5118J
We have derived abundances of O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe,
Ni, and Ba for 43 metal-poor field stars in the solar neighbourhood,
most of them subgiants or turn-off-point stars with iron abundances
[Fe/H] ranging from -0.4 to -3.0. About half of this sample has not been
spectroscopically analysed in detail before. Effective temperatures
were estimated from uvby photometry, and surface gravities primarily
from Hipparcos parallaxes. The analysis is differential relative to
the Sun, and was carried out with plane-parallel MARCS models. Various
sources of error are discussed and found to contribute a total error
of about 0.1-0.2 dex for most elements, while relative abundances,
such as [Ca/Fe], are most probably more accurate. For the oxygen
abundances, determined in an NLTE analysis of the 7774 Å triplet
lines, the errors may be somewhat larger. We made a detailed comparison
with similar studies and traced the reasons for the, in most cases,
relatively small differences. Among the results we find that [O/Fe]
possibly increases beyond [Fe/H] = -1.0, though considerably less so
than in results obtained by others from abundances based on OH lines. We
did not trace any tendency toward strong overionization of iron, and
find the excesses, relative to Fe and the Sun, of the α elements Mg,
Si, and Ca to be smaller than those of O. We discuss some indications
that also the abundances of different α elements relative to Fe vary
and the possibility that some of the scatter around the trends in
abundances relative to iron may be real. This may support the idea that
the formation of Halo stars occurred in smaller systems with different
star formation rates. We verify the finding by Gratton et al. (2003b,
A&A, 406, 131) that stars that do not participate in the rotation
of the galactic disk show a lower mean and larger spread in [ α/Fe]
than stars participating in the general rotation. The latter stars also
seem to show some correlation between [ α/Fe] and rotation speed. We
trace some stars with peculiar abundances, among these two Ba stars,
<ASTROBJ>HD 17072</ASTROBJ> and <ASTROBJ>HD 196944</ASTROBJ>, the
second already known to be rich in s elements. Finally we advocate
that a spectroscopic study of a larger sample of halo stars with
well-defined selection criteria is very important, in order to add to
the very considerable efforts that various groups have already made.
---------------------------------------------------------
Title: Discovery of a bright quasar without a massive host galaxy
Authors: Magain, Pierre; Letawe, Géraldine; Courbin, Frédéric;
Jablonka, Pascale; Jahnke, Knud; Meylan, Georges; Wisotzki, Lutz
2005Natur.437..381M Altcode: 2005astro.ph..9433M
A quasar is thought to be powered by the infall of matter onto a
supermassive black hole at the centre of a massive galaxy. Because
the optical luminosity of quasars exceeds that of their host galaxy,
disentangling the two components can be difficult. This led in
the 1990s to the controversial claim of the discovery of `naked'
quasars. Since then, the connection between quasars and galaxies has
been well established. Here we report the discovery of a quasar lying
at the edge of a gas cloud, whose size is comparable to that of a small
galaxy, but whose spectrum shows no evidence for stars. The gas in the
cloud is excited by the quasar itself. If a host galaxy is present,
it is at least six times fainter than would normally be expected for
such a bright quasar. The quasar is interacting dynamically with a
neighbouring galaxy, whose gas might be feeding the black hole.
---------------------------------------------------------
Title: Time Delay in Gravitational Lenses: an Alternative Route to
the Hubble Constant
Authors: Magain, P.
2005ASPC..335..207M Altcode:
The gravitational lens phenomenon is briefly introduced. When several
images of the same variable quasar are observed, a determination of
the time delay, i.e. the difference in light travel time between
these different images can lead to a determination of distances
between the source, the lens and the observer and, thus, of the Hubble
constant. These determinations are compared to the more classical ones
based on standard candles (Cepheids and Type Ia Supernovae).
---------------------------------------------------------
Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses
Authors: Courbin, F.; Eigenbrod, A.; Vuissoz, C.; Meylan, G.;
Magain, P.
2005IAUS..225..297C Altcode:
We describe a new project aiming at measuring time delays for most
known lensed quasars, from optical light curves obtained with five
(almost) dedicated 1-2 m telescopes in the Northern and Southern
hemispheres. The goal is to evaluate the Hubble constant H<SUB>0</SUB>
with a precision below 2%. We present here numerical simulations in
order to define the optimal temporal sampling in our observations as
a function of typical quasar variations, object visibility, and for
a given accuracy on the individual photometric points. It is also
emphasized that the ongoing effort to obtain deep imaging using both
space and ground based facilities must be continued, as illustrated
by the comparison of HST and VLT near-IR images of the `cloverleaf':
H 1413+117.
---------------------------------------------------------
Title: VizieR Online Data Catalog: Chemical abundances in 43
metal-poor stars (Jonsell+, 2005)
Authors: Jonsell, K.; Edvardsson, B.; Gustafsson, B.; Magain, P.;
Nissen, P. E.; Asplund, M.
2005yCat..34400321J Altcode:
Data from an analysis of 43 metal-poor field stars with iron abundances
[Fe/H] ranging from -0.4 to -3.0dex are presented here. Photometric
data, stellar velocities, masses, fundamental parameters, spectral
classifications and notations of possible binarity are given. Tables
with line data for O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe, Ni and
Ba, equivalent widths and resulting abundances are also given. <P />(4
data files).
---------------------------------------------------------
Title: Abundance correlations in mildly metal-poor stars. II. Light
elements (C to Ca)
Authors: Decauwer, H.; Jehin, E.; Parmentier, G.; Magain, P.
2005A&A...433..285D Altcode:
Accurate relative abundances have been obtained for carbon, oxygen,
sodium, aluminium, silicon, and calcium in a sample of mildly metal-poor
stars. This analysis complements a previous study carried out by Jehin
et al. ([CITE], A&A, 341, 241), which provided the basis for the
EASE scenario. This scenario postulates that field metal-poor stars
were born in self-enriched proto-globular cluster clouds. By further
investigating the correlations between the different α-element
abundances, we propose a modified scenario for the formation of
intermediate metallicity stars, in which the stars exhibiting lower than
average α/Fe abundance ratios would form in low mass clouds, unable to
sustain the formation of very massive stars (M ⪆ 30~M_⊙). Moreover,
the carbon-to-iron ratio is found to decrease as one climbs the
so-called Population IIb branch, i.e. when the s-element abundance
increases. In the framework of the EASE scenario, we interpret this
anticorrelation between the carbon and the s-element abundances as a
signature of a hot bottom burning process in the metal-poor AGB stars
which expelled the matter subsequently accreted by our Population IIb
stars. <P />Based on observations collected at the European Southern
Observatory, La Silla, Chile (ESO Programmes 56.E-0384, 57.E-0400
and 59.E-0257).
---------------------------------------------------------
Title: The Influence of Blends on the Potential of Extrasolar Planets
Transit Surveys
Authors: Gillon, M.; Magain, P.; Guillot, T.; Fressin, F.
2005prpl.conf.8151G Altcode: 2005LPICo1286.8151G
No abstract at ADS
---------------------------------------------------------
Title: α-elements in mildly metal-poor stars
Authors: Decauwer, H.; Jehin, E.; Parmentier, G.; Magain, P.
2005IAUS..228..393D Altcode:
Accurate relative abundances of light elements (C to Ca) have
been obtained in a sample of mildly metal-poor stars (Decauwer et
al. 2005). Combined with the results of a previous study (Jehin et
al. 1999), we find different slopes in the correlations between the
different α-elements. These results can be explained by postulating
that the stars exhibiting lower than average α/Fe form in low mass
clouds, unable to sustain the formation of very massive stars.
---------------------------------------------------------
Title: Chemical abundances in 43 metal-poor stars
Authors: Gustafsson, Bengt; Asplund, Martin; Edvardsson, Bengt;
Jonsell, Karin; Magain, Pierre; Nissen, Poul Erik
2005IAUS..228..259G Altcode:
We have derived abundances of O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe,
Ni and Ba for 43 metal-poor field stars, mostly stars at the turn-off
point and on the subgiant branch, in the interval {-}3.0{[Fe/H]{. The
analysis is differential relative to the Sun. Oxygen abundances,
with consideration of NLTE effects, were derived from the OI 777.4 nm
triplet lines. We find [O/Fe] to gradually increase with decreasing
[Fe/H], though considerably slower than has earlier been obtained from
OH lines in the UV. A scatter in [O,Mg,Ca,Ti/Fe] at a given [Fe/H] is
found and we argue that this scatter is partly real. The deviations from
the mean trends of abundance ratios vs [Fe/H] are found to correlate
in non-trivial ways for different abundances. Similar trends are found
from results of accurate studies by other groups. This seems to give
further evidence for the hypothesis that the stars once formed in
different subsystems, with different star-formation rates.The paper
is in press in A&A, may be obtained as astro-ph/0505118.
---------------------------------------------------------
Title: Abundance analysis of targets for the COROT/MONS
asteroseismology missions. II. Abundance analysis of the COROT
main targets
Authors: Bruntt, H.; Bikmaev, I. F.; Catala, C.; Solano, E.; Gillon,
M.; Magain, P.; Van't Veer-Menneret, C.; Stütz, C.; Weiss, W. W.;
Ballereau, D.; Bouret, J. C.; Charpinet, S.; Hua, T.; Katz, D.;
Lignières, F.; Lueftinger, T.
2004A&A...425..683B Altcode: 2004astro.ph..3464B
One of the goals of the ground-based support program for the COROT
and MONS/RÖMER satellite missions is to characterize suitable target
stars for the part of the missions dedicated to asteroseismology. We
present the detailed abundance analysis of nine of the potential
COROT main targets using the semi-automatic software VWA. For two
additional COROT targets we could not perform the analysis due to
the high rotational velocity of these stars. For five stars with low
rotational velocity we have also performed abundance analysis by a
classical equivalent width method in order to test the reliability
of the VWA software. The agreement between the different methods is
good. We find that it is necessary to measure abundances extracted
from each line relative to the abundances found from a spectrum of
the Sun in order to remove systematic errors. We have constrained the
global atmospheric parameters T<SUB>eff</SUB>, log g, and [Fe/H] to
within 70-100 K, 0.1-0.2 dex, and 0.1 dex for five stars which are slow
rotators (v sin i < 15 km s<SUP>-1</SUP>). For most of the stars we
find good agreement with the parameters found from line depth ratios,
H α lines, Strömgren indices, previous spectroscopic studies, and also
log g determined from the HIPPARCOS parallaxes. For the fast rotators
(v sin i > 60 km s<SUP>-1</SUP>) it is not possible to constrain
the atmospheric parameters. <P />Based on observations obtained with
the 193 cm telescope at Observatoire de Haute Provence, France.
---------------------------------------------------------
Title: On-axis spectroscopy of the z =0.144 radio-loud quasar HE
1434-1600: an elliptical host with a highly ionized ISM
Authors: Letawe, G.; Courbin, F.; Magain, P.; Hilker, M.; Jablonka,
P.; Jahnke, K.; Wisotzki, L.
2004A&A...424..455L Altcode: 2004astro.ph..5309L
VLT on-axis optical spectroscopy of the z=0.144 radio-loud quasar
HE 1434-1600 is presented. The spatially resolved spectra of the
host galaxy are deconvolved and separated from those of the central
quasar in order to study the dynamics of the stars and gas as well
as the physical conditions of the ISM. We find that the host of
HE 1434-1600 is an elliptical galaxy that resides in a group of at
least 5 member galaxies, and that most likely experienced a recent
collision with its nearest companion. Compared with other quasar host
galaxies, HE 1434-1600 has a highly ionized ISM. The ionization state
corresponds to that of typical Seyferts, but the ionized regions are
not distributed in a homogeneous way around the QSO, and are located
preferentially several kiloparsecs away from it. While the stellar
absorption lines do not show any significant velocity field, the gas
emission lines do. The observed gas velocity field is hard to reconcile
with dynamical models involving rotating disk, modified Hubble laws or
power laws, that all require extreme central masses (M>10<SUP>9</SUP>
M<SUB>⊙</SUB>) to provide only poor fit to the data. Power law models,
which best fit the data, provide a total mass of M(<10 kpc) = 9.2 ×
10<SUP>10</SUP> M<SUB>⊙</SUB>. We conclude that the recent interaction
between HE 1434-1600 and its closest companion has strongly affected
the gas velocity and ionization state, from the center of the galaxy
to its most external parts. <P />Based on observations made with the
ESO Very Large Telescope ANTU/UT1 at ESO-Paranal observatory, Chile
(program 65.P-0361(A)).
---------------------------------------------------------
Title: Accretion of Gas by Globular Cluster Stars
Authors: Thoul, A.; Jehin, E.; Magain, P.; Noels, A.; Parmentier,
G.; Jorissen, A.; Goriely, S.
2003ASPC..296..315T Altcode: 2003nhgc.conf..315T
No abstract at ADS
---------------------------------------------------------
Title: On-axis VLT spectroscopy of quasar host galaxies: HE 1503+0228,
at z=0.135
Authors: Courbin, F.; Letawe, G.; Magain, P.; Wisotzki, L.; Jablonka,
P.; Jahnke, K.; Kuhlbrodt, B.; Alloin, D.; Meylan, G.
2003ASPC..290..491C Altcode: 2003agnc.conf..491C
No abstract at ADS
---------------------------------------------------------
Title: p-mode Oscillations of α Cen A
Authors: Thoul, A.; Scuflaire, R.; Vatovez, B.; Noels, A.; Magain,
P.; Briquet, M.; Dupret, M. -A.
2003Ap&SS.284..241T Altcode:
Models of α Cen A & B have been computed using the masses
determined by Pourbaix et al. (2002) and the data derived from the
spectroscopic analysis of Neuforge and Magain (1997). The seismological
data obtained by Bouchy and Carrier (2001, 2002) do help improve
our knowledge of the evolutionary status of the system. All the
constraints are satisfied with a model which gives an age of about 6
Gyr for the binary.
---------------------------------------------------------
Title: Variable Blue Stragglers and the EASE Scenario
Authors: Noels, A.; Scuflaire, R.; Magain, P.; Parmentier, G.;
Thoul, A.
2003aahd.conf..437N Altcode:
No abstract at ADS
---------------------------------------------------------
Title: On-axis spatially resolved spectroscopy of low redshift quasar
host galaxies: HE 1503+0228, at z=0.135
Authors: Courbin, F.; Letawe, G.; Magain, P.; Wisotzki, L.; Jablonka,
P.; Jahnke, K.; Kuhlbrodt, B.; Alloin, D.; Meylan, G.; Minniti, D.;
Burud, I.
2002A&A...394..863C Altcode: 2002astro.ph..8514C
We present the first result of a comprehensive spectroscopic study
of quasar host galaxies. On-axis, spatially resolved spectra of low
redshift quasars have been obtained with FORS1, mounted on the 8.2 m ESO
Very Large Telescope, Antu. The spectra are spatially deconvolved using
a spectroscopic version of the “MCS deconvolution algorithm”. The
algorithm decomposes two dimensional spectra into the individual spectra
of the central point-like nucleus and of its host galaxy. Applied
to HE 1503+0228 at z=0.135 (M<SUB>B</SUB>=-23.0), it provides us
with the spectrum of the host galaxy between 3600 Å and 8500 Å
(rest-frame), at a mean resolving power of 700. The data allow us to
measure several of the important Lick indices. The stellar populations
and gas ionization state of the host galaxy of HE 1503+0228 are very
similar to the ones measured for normal non-AGN galaxies. Dynamical
information is also available for the gas and stellar components of
the galaxy. Using deconvolution and a deprojection algorithm, velocity
curves are derived for emission lines, from the center up to 4\arcsec
away from the nucleus of the galaxy. Fitting a simple three-components
mass model (point mass, spherical halo of dark matter, disk) to the
position-velocity diagram, we infer a mass of M(r<1 kpc) = (2.0 +/-
0.3)x 10<SUP>10</SUP> M<SUB>sun</SUB> within the central kiloparsec
of the galaxy, and a mass integrated over 10 kpc of M(r<10 kpc) =
(1.9 +/- 0.3) x 10<SUP>11</SUP> M<SUB>sun</SUB>, with an additional 10%
error due to the uncertainty on the inclination of the galaxy. This,
in combination with the analysis of the stellar populations indicates
that the host galaxy of HE 1503+0228, is a normal spiral galaxy. Based
on observations made with ANTU/UT1 at ESO-Paranal observatory in
Chile (program 65.P-0361(A)), and with the ESO 3.5 m NTT, at La Silla
observatory (program 62.P-0643(B)).
---------------------------------------------------------
Title: Time delay and lens redshift for the doubly imaged BAL quasar
SBS 1520+530
Authors: Burud, I.; Hjorth, J.; Courbin, F.; Cohen, J. G.; Magain,
P.; Jaunsen, A. O.; Kaas, A. A.; Faure, C.; Letawe, G.
2002A&A...391..481B Altcode: 2002astro.ph..6084B
We present optical R-band light curves of the gravitationally lensed
quasar <ASTROBJ>SBS 1520+530</ASTROBJ> derived from data obtained at
the Nordic Optical Telescope. A time delay of 130+/-3 days (1sigma
) is determined from the light curves. In addition, spectra of
<ASTROBJ>SBS 1520+530</ASTROBJ> obtained at the Keck Observatory
are spatially deconvolved in order to extract the spectrum of the
faint lensing galaxy, free of any contamination by the light from
the bright quasar images. This spectrum indicates a lens redshift
z=0.717, in agreement with one of the absorption systems found in
the quasar spectra. The best mass model of the system includes a
second nearby galaxy and a cluster of galaxies in addition to the
main lensing galaxy. Adopting this model and an Omega =0.3, Lambda
=0.7 cosmology, our time-delay measurement yields a Hubble constant
of H<SUB>0</SUB>=51 +/- 9 km s<SUP>-1</SUP> Mpc<SUP>-1</SUP> (1sigma
error). Based on observations made with the Nordic Optical, operated on
the island of La Palma jointly by Denmark, Finland, Iceland, Norway,
and Sweden, in the Spanish Observatorio del Roque de los Muchachos of
the Instituto de Astrofisica de Canarias and the W. M. Keck Observatory
which is operated jointly by the California Institute of Technology,
the University of California and the National Aeronautics and Space
Administration. Table 2 is only available in electronic form at the
CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/391/481
---------------------------------------------------------
Title: VizieR Online Data Catalog: R-band photometry of SBS1520+530
(Burud+, 2002)
Authors: Burud, I.; Hjorth, J.; Courbin, F.; Cohen, J. G.; Magain,
P.; Jaunsen, A. O.; Kaas, A. A.; Faure, C.; Letawe, G.
2002yCat..33910481B Altcode:
The table lists the data points obtained at the Nordic Optical Telescope
used to derive the time delay for the lensed quasar QSO1520+530. (1
data file).
---------------------------------------------------------
Title: Spectroscopy of quasar host galaxies at the VLT: stellar
populations and dynamics down to the central kiloparsec
Authors: Courbin, F.; Letawe, G.; Magain, P.; Wisotzki, L.; Jablonka,
P.; Alloin, D.; Jahnke, K.; Kuhlbrodt, B.; Meylan, G.; Minniti, D.
2002Msngr.107...28C Altcode:
1. Scientific Context 2. VLT Spectroscopic Observations 3. Spectra
Decomposition and Stellar Population 4. Dynamics of the Host 5. Towards
2D Spectroscopy and High Spatial Resolution: GIRAFFE, SINFONI and FALCON
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Title: Accretion of gas by globular cluster stars
Authors: Thoul, A.; Jorissen, A.; Goriely, S.; Jehin, E.; Magain,
P.; Noels, A.; Parmentier, G.
2002A&A...383..491T Altcode: 2002astro.ph..1341T
Some recent observations of the abundances of s-process, r-process,
and alpha elements in metal-poor stars have led to a new scenario
for their formation. According to this scenario, these stars were
born in a globular cluster and accreted the s-process enriched gas
expelled by cluster stars of higher-mass, thereby modifying their
surface abundances. Later on, these polluted stars evaporated from the
globular cluster to constitute an important fraction of the current
halo population. In addition, there are now many direct observations
of abundance anomalies not only in globular cluster giant stars but
also in subgiant and main-sequence stars. Accretion again provides a
plausible explanation for (at least some of) these peculiarities. Here
we investigate further the efficiency of the accretion scenario. We find
that in concentrated clusters with large escape velocities, accretion
is very efficient and can indeed lead to major modifications of the
stellar surface abundances.
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Title: Metallicity Gradients in Globular Cluster Systems : the Trace
of a Self-Enrichment Process ?
Authors: Parmentier, G.; Magain, P.; Noels, A.; Thoul, A.; Jehin, E.
2002IAUS..207..733P Altcode:
We have developed a model of globular cluster self-enrichment, based
on the ability of the globular cluster gaseous progenitors to retain
the ejecta of a first generation of Type II Supernovae. The key point
is that this ability depends on the pressure exerted on the progenitor
cloud by the surrounding protogalactic medium and therefore on the
location of the cloud in the protogalaxy. The model is able to explain
the galactic halo metallicities and the metallicity gradient of the
Old Halo which is thought to be the genuine galactic globular cluster
system. The possibility that metallicity gradients are a common property
of extragalactic globular cluster systems is also presented.
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Title: Evidence For a Self-Enrichment Process in Galactic Halo
Globular Clusters
Authors: Parmentier, G.; Jehin, E.; Magain, P.; Noels, A.; Thoul, A.
2002ASPC..285..234P Altcode: 2002msfo.conf..234P
No abstract at ADS
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Title: An optical time-delay for the lensed BAL quasar HE 2149-2745
Authors: Burud, I.; Courbin, F.; Magain, P.; Lidman, C.; Hutsemékers,
D.; Kneib, J. -P.; Hjorth, J.; Brewer, J.; Pompei, E.; Germany, L.;
Pritchard, J.; Jaunsen, A. O.; Letawe, G.; Meylan, G.
2002A&A...383...71B Altcode: 2001astro.ph.12225B
We present optical V and i-band light curves of the gravitationally
lensed BAL quasar HE 2149-2745. The data, obtained with the 1.5 m Danish
Telescope (ESO-La Silla) between October 1998 and December 2000, are
the first from a long-term project aimed at monitoring selected lensed
quasars in the Southern Hemisphere. A time delay of 103+/-12 days is
determined from the light curves. In addition, VLT/FORS1 spectra of HE
2149-2745 are deconvolved in order to obtain the spectrum of the faint
lensing galaxy, free of any contamination by the bright nearby two
quasar images. By cross-correlating the spectrum with galaxy-templates
we obtain a tentative redshift estimate of z=0.495+/-0.01. Adopting this
redshift, a Omega =0.3, Lambda =0.7 cosmology, and a chosen analytical
lens model, our time-delay measurement yields a Hubble constant of
H<SUB>0</SUB>=66 +/- 8 km s<SUP>-1</SUP> Mpc<SUP>-1</SUP> (1sigma
error) with an estimated systematic error of +/-3 km s<SUP>-1</SUP>
Mpc<SUP>-1</SUP>. Using non-parametric models yields H<SUB>0</SUB>=65
+/- 8 km s<SUP>-1</SUP> Mpc<SUP>-1</SUP> (1sigma error) and confirms
that the lens exhibits a very dense/concentrated mass profile. Finally,
we note, as in other cases, that the flux ratio between the two quasar
components is wavelength dependent. While the flux ratio in the broad
emission lines - equal to 3.7 - remains constant with wavelength,
the continuum of the brighter component is bluer. Although the data do
not rule out extinction of one quasar image relative to the other as a
possible explanation, the effect could also be produced by differential
microlensing by stars in the lensing galaxy. Based on observations
made with the Danish 1.5-m telescope (ESO, La Silla, Chile) and at VLT
UT1 Antu (ESO-Paranal, Chile) (Proposals: 64.O-0205(B), 65.O-0214(B),
66.A-0203(B), 67.A-0115(B), 66.B-0139(A) and HST archives ID 8175).
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Title: A novel approach for extracting time-delays from lightcurves
of lensed quasar images
Authors: Burud, I.; Magain, P.; Sohy, S.; Hjorth, J.
2001A&A...380..805B Altcode: 2001astro.ph.10668B
We present a new method to estimate time delays from light curves of
lensed quasars. The method is based on chi <SUP>2</SUP> minimization
between the data and a numerical model light curve. A linear variation
can be included in order to correct for slow long-term microlensing
effects in one of the lensed images. An iterative version of the method
can be applied in order to correct for higher-order microlensing
effects. The method is tested on simulated light curves. When
higher-order microlensing effects are present, the time delay is best
constrained with the iterative method. Analysis of a published data
set for the lensed double Q 0957+561 yields results in agreement with
other published estimates.
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Title: Deconvolving Spectra: Near-IR Spectroscopy of the Lens and
Source in HE 1104-1805
Authors: Courbin, F.; Lidman, C.; Meylan, G.; Magain, P.
2001ASPC..237...85C Altcode: 2001glrp.conf...85C
No abstract at ADS
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Title: What Happens to the Gas in Globular Clusters?
Authors: Thoul, A.; Jehin, E.; Magain, P.; Noels, A.; Parmentier, G.
2001ASPC..228..571T Altcode: 2001dscm.conf..571T
No abstract at ADS
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Title: An Optical Time Delay Estimate for the Double Gravitational
Lens System B1600+434
Authors: Burud, I.; Hjorth, J.; Jaunsen, A. O.; Andersen, M. I.;
Korhonen, H.; Clasen, J. W.; Pelt, J.; Pijpers, F. P.; Magain, P.;
Østensen, R.
2000ApJ...544..117B Altcode: 2000astro.ph..7136B
We present optical I-band light curves of the gravitationally
lensed double QSO B1600+434 from observations obtained at the Nordic
Optical Telescope (NOT) between 1998 April and 1999 November. The
photometry has been performed by simultaneous deconvolution of all
the data frames, involving a numerical lens galaxy model. Four
methods have been applied to determine the time delay between
the two QSO components, giving a mean estimate of Δt=51+/-4 days
(95% confidence level). This is the fourth optical time delay ever
measured. Adopting a Ω=0.3, Λ=0 universe and using the mass model
of Maller et al., this time delay estimate yields a Hubble parameter
of H<SUB>0</SUB>=52<SUP>+14</SUP><SUB>-8</SUB> km s<SUP>-1</SUP>
Mpc<SUP>-1</SUP> (95% confidence level), where the errors include time
delay as well as model uncertainties. There are time-dependent offsets
between the two (appropriately shifted) light curves that indicate
the presence of external variations due to microlensing. Based on
observations made with the Nordic Optical Telescope, operated on the
island of La Palma jointly by Denmark, Finland, Iceland, Norway, and
Sweden, in the Spanish Observatorio del Roque de los Muchachos of the
Instituto de Astrofisica de Canarias.
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Title: The Old Halo metallicity gradient: the trace of a
self-enrichment process
Authors: Parmentier, G.; Jehin, E.; Magain, P.; Noels, A.; Thoul, A. A.
2000A&A...363..526P Altcode: 2000astro.ph..9477P
Based on a model of globular cluster self-enrichment published in a
previous paper, we present an explanation for the metallicity gradient
observed throughout the galactic Old Halo. Our self-enrichment model is
based on the ability of globular cluster progenitor clouds to retain
the ejecta of a first generation of Type II Supernovae. The key point
is that this ability depends on the pressure exerted on the progenitor
cloud by the surrounding protogalactic medium and therefore on the
location of the cloud in the protoGalaxy. Since there is no significant
(if any) metallicity gradient in the whole halo, we also present a
review in favour of a galactic halo partly built via accretions and
mergers of satellite systems. Some of them bear their own globular
clusters and therefore “contaminate” the system of globular clusters
formed “in situ”, namely within the original potential well of the
Galaxy. Therefore, the comparison between our self-enrichment model
and the observational data should be limited to the genuine galactic
globular clusters, the so-called Old Halo group.
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Title: Lensed quasars: a matter of resolution
Authors: Courbin, F.; Lidman, C.; Burud, I.; Hjorth, J.; Magain, P.;
Golse, G.; Castander, F.
2000Msngr.101...20C Altcode: 2000Msngr.101...17C
The interest in studying lensed quasars amongst the astronomical
community has always been somewhat fluctuating. Periods of great
enthusiasm and of profound disappointment have regularly followed
one another.
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Title: Exploring the gravitationally lensed system HE 1104-1805:
near-IR spectroscopy
Authors: Courbin, F.; Lidman, C.; Meylan, G.; Kneib, J. -P.; Magain, P.
2000A&A...360..853C Altcode: 2000astro.ph..6168C
A new technique for the spatial deconvolution of spectra is applied to
near-IR (0.95-2.50 μm) NTT/SOFI spectra of the lensed, radio-quiet
quasar HE 1104-1805. The continuum of the lensing galaxy is revealed
between 1.5 μm and 2.5 μm. Although the spectrum does not show strong
emission features, it is used in combination with previous optical
and IR photometry to infer a plausible redshift in the range 0.8 <
z < 1.2. Modeling of the system shows that the lens is complex,
probably composed of the red galaxy seen between the quasar images
and a more extended component associated with a galaxy cluster with
fairly low velocity dispersion (~ 575 km s<SUP>-1</SUP>). Unless
more constrains can be put on the mass distribution of the cluster,
e.g. from deep X-ray observations, HE 1104-1805 will not be a good
system to determine H<SUB>0</SUB>. We stress that multiply imaged
quasars with known time delays may prove more useful as tools
for detecting dark mass in distant lenses than for determining
cosmological parameters. The spectra of the two lensed images of the
source are of great interest. They show no trace of reddening at the
redshift of the lens nor at the redshift of the source. This supports
the hypothesis of an elliptical lens. Additionally, the difference
between the spectrum of the brightest component and that of a scaled
version of the faintest component is a featureless continuum. Broad
and narrow emission lines, including the FeII features, are perfectly
subtracted. The very good quality of our spectrum makes it possible
to fit precisely the optical Fe II feature, taking into account the
underlying continuum over a wide wavelength range. HE 1104-1805 can be
classified as a weak Fe II emitter. Finally, the slope of the continuum
in the brightest image is steeper than the continuum in the faintest
image and supports the finding by Wisotzki et al. (1993) that the
brightest image is microlensed. This is particularly interesting in
view of the new source reconstruction methods from multiwavelength
photometric monitoring. While HE 1104- 1805 does not seem the best
target for determining cosmological parameters, it is probably the
second most interesting object after Q 2237+0305 (the Einstein cross),
in terms of microlensing. Based on observations collected with the
ESO New Technology Telescope (program 61.B-0413)
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Title: Resolved stellar populations of super-metal-rich star clusters
in the bulge of M 31
Authors: Jablonka, P.; Courbin, F.; Meylan, G.; Sarajedini, A.;
Bridges, T. J.; Magain, P.
2000A&A...359..131J Altcode: 2000astro.ph..5040J
We have applied the MCS image deconvolution algorithm (Magain et
al. 1998) to HST/WFPC2 V, I data of three M 31 bulge globular clusters
(G170, G177, and G198) and control fields near each cluster. All three
clusters are clearly detected, with an increase in stellar density
with decreasing radius from the cluster centers; this is the first time
that stars have been resolved in bulge clusters in the inner regions of
another galaxy. From the RGB slopes of the clusters and the difference
in I magnitude between the HB and the top of the RGB, we conclude that
these three clusters all have roughly solar metallicity, in agreement
with earlier integrated-light spectroscopic measurements. Our data
support a picture whereby the M 31 bulge clusters and field stars were
born from the same metal-rich gas, early in the galaxy formation.
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Title: Were the Old Halo globular clusters able to sustain a
self-enrichment phase?
Authors: Parmentier, Geneviève; Jehin, Emmanuel; Magain, Pierre;
Noels, Arlette; Thoul, Anne
2000NewAR..44..351P Altcode:
It has been argued for a long time that the self-enrichment process
could not occur within proto-globular clouds because of the supernova
energetics. We revisit this argument and demonstrate that it may
not be true. Since not all the kinetic energy of Type II Supernovae
is deposited as kinetic energy of the ISM, we suggest comparing the
binding energy of the progenitor cloud to the kinetic energy of the
ISM instead of the kinetic energy of the Type II Supernova ejecta. This
criterion is used to study the disruptive ability of Type II Supernovae
onto proto-globular clouds. It is found that the early chemical history
of globular clusters is greatly influenced by the pressure exerted by
the external medium on their progenitor clouds.
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Title: Observational Constraints on a Self-Enrichment Model in
Galactic Halo Globular Clusters
Authors: Parmentier, G.; Jehin, E.; Magain, P.; Noels, A.; Thoul, A.
2000ESASP.445..483P Altcode: 2000sfsl.conf..483P
No abstract at ADS
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Title: A Method for Spatial Deconvolution of Spectra
Authors: Courbin, F.; Magain, P.; Kirkove, M.; Sohy, S.
2000ApJ...529.1136C Altcode: 1999astro.ph..9109C
A method for spatial deconvolution of spectra is presented. It follows
the same fundamental principles as the “MCS image deconvolution
algorithm” recently developed by Magain, Courbin, & Sohy and
uses information contained in the spectrum of a reference point-spread
function to spatially deconvolve spectra of very blended sources. An
improved resolution rather than an infinite one is aimed at, overcoming
the well-known problem of “deconvolution artifacts.” As in the
MCS algorithm, the data are decomposed into a sum of analytical point
sources and a numerically deconvolved background so that the spectrum of
extended sources in the immediate vicinity of bright point sources may
be accurately extracted and sharpened. The algorithm has been tested on
simulated data including seeing variation as a function of wavelength
and atmospheric refraction. It is shown that the spectra of severely
blended point sources can be resolved while fully preserving the
spectrophotometric properties of the data. Extended objects “hidden”
by bright point sources (up to 4-5 mag brighter) can be accurately
recovered as well, provided the data have a sufficiently high total
signal-to-noise ratio (200-300 per spectral resolution element). Such
spectra are relatively easy to obtain, even down to faint magnitudes,
within a few hours of integration time with 10 m class telescopes.
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Title: POX 186: the ultracompact blue compact dwarf galaxy reveals
its nature
Authors: Doublier, V.; Kunth, D.; Courbin, F.; Magain, P.
2000A&A...353..887D Altcode: 1999astro.ph..2294D; 1999astro.ph..2294V
High resolution, ground based R and I band observations of the ultra
compact dwarf galaxy POX 186 are presented. The data, obtained with
the ESO New Technology Telescope (NTT), are analyzed using a new
deconvolution algorithm which allows one to resolve the innermost
regions of this stellar-like object into three Super-Star Clusters
(SSC). Upper limits to both masses (M ~ 10<SUP>5</SUP> M<SUB>sun</SUB>)
and physical sizes (<=60pc) of the SSCs are set. In addition,
and maybe most importantly, extended light emission underlying the
compact star-forming region is clearly detected in both bands. The R-I
color rules out nebular Hα contamination and is consistent with an old
stellar population. This casts doubt on the hypothesis that Blue Compact
Dwarf Galaxies (BCDG) are young galaxies. based on observations carried
out at NTT in La Silla, operated by the European Southern Observatory,
during Director's Discretionary Time.
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Title: Abundance correlations in thick disk and halo stars
Authors: Jehin, E.; Magain, P.; Noels, A.; Parmentier, G.; Thoul, A.
2000LIACo..35..151J Altcode: 2000ghgc.conf..151J
No abstract at ADS
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Title: On the possibility of self-enrichement in globular clusters
Authors: Parmentier, G.; Jehin, E.; Magain, P.; Neuforge, C.; Noels,
A.; Thoul, A. A.
2000LIACo..35..561P Altcode: 2000ghgc.conf..561P
No abstract at ADS
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Title: Puzzling locations of mildly metal-poor stars in the HR diagram
Authors: Jehin, E.; Noels, A.; Magain, P.; Parmentier, G.; Thoul, A.
2000LIACo..35..231J Altcode: 2000ghgc.conf..231J
No abstract at ADS
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Title: The metallicity gradient of the old halo
Authors: Parmentier, G.; Jehin, E.; Magain, P.; Noels, A.; Thoul, A.
2000LIACo..35..623P Altcode: 2000ghgc.conf..623P
No abstract at ADS
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Title: Accretion from AGB winds.
Authors: Thoul, A.; Jorissen, A.; Goriely, S.; Jehin, E.; Magain,
P.; Noels, A.; Parmentier, G.
2000MmSAI..71..791T Altcode:
No abstract at ADS
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Title: The EASE Scenario: Dynamical Study of the Supernova Phase
Authors: Parmentier, Geneviève; Jehin, Emannuel; Magain, Pierre;
Noels, Arlette; Thoul, Anne
2000fist.conf..199P Altcode:
We revisit the most often encountered argument against self-enrichment
in globular clusters, namely the ability of a few number of supernovae
to disrupt the proto-globular cloud. We show that, within the context
of the Fall and Rees theory, primordial proto-globular cluster clouds
may sustain several hundreds of Type II supernovae. Furthermore, the
corresponding self-enrichment level is in agreement with galactic halo
globular cluster metallicities.
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Title: The Galactic Halo : from Globular Clusters to Field Stars
Authors: Noels, A.; Magain, P.; Caro, D.; Jehin, E.; Parmentier, G.;
Thoul, A. A.
2000LIACo..35.....N Altcode: 2000ghgc.conf.....N
The following topics were dealt with: early galactic nucleosynthesis;
chemical composition of metal-poor stars; metal-poor components of
our Galaxy; HR diagrams of globular clusters; chemical and dynamical
evolution of globular clusters.
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Title: Accretion processes onto globular cluster stars
Authors: Thoul, A.; Jorissen, A.; Goriely, S.; Jehin, E.; Magain,
P.; Noels, A.; Parmentier, G.
2000LIACo..35..567T Altcode: 2000ghgc.conf..567T
No abstract at ADS
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Title: What Happens to the Gas in Globular Clusters?
Authors: Thoul, A.; Jehin, E.; Magain, P.; Noels, A.; Parmentier, G.
2000AGM....16..P86T Altcode:
Observations of globular clusters show that they contain much too
little gas or dust, compared to what should be present due to the
mass-losing stars in the cluster. Many authors have been intrigued
by the fate of the gas in globular clusters. They have suggested
various mechanisms by which the gas could escape from the cluster,
such as stellar UV radiation, cluster winds driven by X-ray bursters,
novae, or flare-stars, relativistic winds from millisecond pulsars,
condensation into stars, accretion processes drawing upon a central
gas reservoir, continuous sweeping of the cluster gas by the gaseous
medium of the Galactic halo dots. Recent results also show that globular
cluster stars show many abundance anomalies. Accretion of interstellar
gas by the cluster stars has been suggested as a plausible mechanism
to explain these anomalies. It is also a major ingredient of the EASE
scenario linking halo field stars to globular clusters, which we have
recently developed to explain strong r-and s-elements correlations
in halo field dwarf stars. Here we will briefly review the status of
gas and dust detection in globular clusters, as well as the possible
gas removal mechanisms. We will explore in more details the gas and
dust accretion processes onto main sequence stars. In particular,
we will study the efficiency of this mechanism in removing gas from
the globular clusters interstellar medium.
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Title: The Galactic halo. From globular clusters to field
stars. Proceedings.
Authors: Noels, A.; Magain, P.; Caro, D.; Jehin, E.; Parmentier, G.;
Thoul, A.
2000ghfg.book.....N Altcode:
The following topics were dealt with: early galactic nucleosynthesis;
chemical composition of metal-poor stars; metal-poor components of
our Galaxy; HR diagrams of globular clusters; chemical and dynamical
evolution of globular clusters.
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Title: The EASE Scenario: A New Origin for Metal-Poor Stars?
Authors: Jehin, Emmanuel; Magain, Pierre; Noels, Arlette; Parmentier,
Geneviève; Thoul, Anne
2000fist.conf..204J Altcode:
We have analysed high resolution and high signal-to-noise spectra
of 21 mildly metal-poor stars. The correlations between the relative
abundances of 16 elements have been studied, with a special emphasis
on the neutron-capture ones. This analysis reveals the existence of two
sub-populations of field metal-poor stars which differ by the behaviour
of the s-process elements versus the α and r-process elements. We
suggest a scenario for the formation of metal-poor stars, which closely
relates the origin of these stars to the evolution of globular clusters.
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Title: Deep Imaging of AX J2019+112: The Luminosity of a “Dark
Cluster”
Authors: Benítez, Narciso; Broadhurst, Tom; Rosati, Piero; Courbin,
Fred; Squires, Gordon; Lidman, Chris; Magain, Pierre
1999ApJ...527...31B Altcode: 1998astro.ph.12218B
We detect a distant cluster of galaxies centered on the
QSO lens and luminous X-ray source AX J2019+112, a.k.a. the
“Dark Cluster.” Using deep V and I Keck images and wide-field
K<SUB>s</SUB> imaging from the New Technology Telescope (NTT),
a tight red sequence of galaxies is identified within a radius
of 0.2 h<SUP>-1</SUP> Mpc of the known z=1.01 elliptical lensing
galaxy. The sequence, which includes the central elliptical galaxy,
has a slope in good agreement with the model predictions of Kodama
et al. for z~1. We estimate the integrated rest-frame luminosity
of the cluster to be L<SUB>V</SUB>>=3.2×10<SUP>11</SUP>
h<SUP>-2</SUP> L<SUB>solar</SUB> (after accounting for significant
extinction at the low latitude of this field), more than an order
of magnitude higher than previous estimates. The central region
of the cluster is deconvolved using the technique of Magain,
Courbin, & Sohy, revealing a thick central arc coincident with
an extended radio source. All the observed lensing features are
readily explained by differential magnification of a radio-loud
active galactic nucleus by a shallow elliptical potential. The QSO
must lie just outside the diamond caustic, producing two images;
the arc is a highly magnified image formed from a region close to
the center of the host galaxy, projecting inside the caustic. The
mass-to-light ratio within an aperture of 0.4 h<SUP>-1</SUP> Mpc is
M<SUB>X</SUB>/L<SUB>V</SUB>=224<SUP>+112</SUP><SUB>-78</SUB>h(M/L<SUB>V</SUB>)<SUB>solar</SUB>,
using the X-ray temperature. The
strong lens model yields a compatible value,
M/L<SUB>V</SUB>=372<SUP>+94</SUP><SUB>-94</SUB>h(M/L<SUB>V</SUB>)<SUB>solar</SUB>,
whereas an independent weak-lensing analysis sets an upper limit of
M/L<SUB>V</SUB><520h(M/L<SUB>V</SUB>)<SUB>solar</SUB>, typical of
massive clusters. <P />Based on observations collected at the European
Southern Observatory, La Silla, Chile, proposal number 61.A-0676.
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Title: The self-enrichment of galactic halo globular clusters. A
clue to their formation?
Authors: Parmentier, G.; Jehin, E.; Magain, P.; Neuforge, C.; Noels,
A.; Thoul, A. A.
1999A&A...352..138P Altcode: 1999astro.ph.11258P
We present a model of globular cluster self-enrichment. In the
protogalaxy, cold and dense clouds embedded in the hot protogalactic
medium are assumed to be the progenitors of galactic halo globular
clusters. The massive stars of a first generation of metal-free stars,
born in the central areas of the proto-globular cluster clouds, explode
as Type II supernovae. The associated blast waves trigger the expansion
of a supershell, sweeping all the material of the cloud, and the heavy
elements released by these massive stars enrich the supershell. A second
generation of stars is born in these compressed and enriched layers
of gas. These stars can recollapse and form a globular cluster. This
work aims at revising the most often encountered argument against
self-enrichment, namely the presumed ability of a small number of
supernovae to disrupt a proto-globular cluster cloud. We describe a
model of the dynamics of the supershell and of its progressive chemical
enrichment. We show that the minimal mass of the primordial cluster
cloud required to avoid disruption by several tens of Type II supernovae
is compatible with the masses usually assumed for proto-globular
cluster clouds. Furthermore, the corresponding self-enrichment level
is in agreement with halo globular cluster metallicities.
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Title: Deconvolving spectra of lensing galaxies, QSO hosts, and
more ...
Authors: Courbin, F.; Magain, P.; Sohy, S.; Lidman, C.; Meylan, G.
1999Msngr..97...26C Altcode:
High spatial resolution undoubtedly plays a key role in most major
advances in observational astrophysics. In this context, considerable
effort has been devoted to the development of numerical methods aimed
at improving the spatial resolution of astronomical images. However,
the most commonly used techniques (e.g., Richardson 1972, Lucy
1974, Skilling & Bryan 1984) tend to produce the so-called
“deconvolution artefacts” (oscillations in the vicinity of
high spatial frequency structures) which alter the photometric
and astrometric properties of the original data. Recently, Magain,
Courbin & Sohy (1998ab; hereafter MCS) proposed and implemented
a new deconvolution algorithm which overcomes such drawbacks. Its
success is mainly the consequence of a deliberate choice to achieve
an improved resolution rather than an infinite one, hence avoiding
retrieving spatial frequencies forbidden by the sampling theorem.
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Title: Linking Field Metal-Poor Stars and Globular Clusters: the
Ease Scenario
Authors: Jehin, E.; Magain, P.; Neuforge, C.; Noels, A.; Parmentier,
G.; Thoul, A.
1999Ap&SS.265..287J Altcode:
No abstract at ADS
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Title: About the origin of extinction in the gravitational lens
system MG J0414+0534
Authors: Angonin-Willaime, M. -C.; Vanderriest, C.; Courbin, F.;
Burud, I.; Magain, P.; Rigaut, F.
1999A&A...347..434A Altcode:
Photometric measurements of the highly reddened gravitational mirage
MG J0414+0534 have been carried out either by PSF subtraction or
by applying accurate deconvolution algorithms to optical (R, I) and
near-infrared (K) images obtained at CFHT and NOT under sub-arcsecond
seeing conditions. It is confirmed that the close pair of images
A1-A2 suffers a larger extinction than B and C. While the colours
of image A2 obtained from ground-based data seem inconsistent with
a simple reddening law, higher resolution images available from
HST archives reveal an additional extended component (arc) which
introduces significant errors in the photometric decomposition. When
the arc component is properly taken into account, the colours of the 4
nucleus images do agree with a classical reddening law, with A2 being
by far the most obscured component. Such a differential extinction
(maximum difference Delta E(R-I) =~ 0.6) is likely due to the lensing
galaxy. This does not mean that {all} the extinction occurs into the
lens. Indeed, the fact that the arc is much less red than the images
of the nucleus suggests that an important part of the reddening is
intrinsic to the source. Finally, no significant variability is
observed within this data set, i.e. between 1994 and 1997, while
a discrepancy from earlier data is noticed for (A1 + A2). Based on
observations collected with the Canada-France-Hawaii Telescope at
Mauna Kea (Hawaii, USA), the Nordic Optical Telescope (Canary, Spain)
and archive data from the Hubble Space Telescope (NASA/ESA)
---------------------------------------------------------
Title: BIMA and Keck Imaging of the Radio Ring PKS 1830-211
Authors: Frye, B. L.; Courbin, F.; Broadhurst, T. J.; Welch, W. J. W.;
Lidman, C.; Magain, P.; Pahre, M.; Djorgovski, S. G.
1999ASPC..156..240F Altcode: 1998astro.ph..2347F; 1999hrrl.conf..240F
We discuss BIMA (Berkeley Illinois Maryland Association) data and
present new h igh quality optical and near-IR Keck images of the
bright radio ring PKS 1830-211. Applying a powerful new deconvolution
algorithm we have been able to identify both images of the radio
source. In addition we recover an extended source in the optical,
consistent with the expected location of the lensing galaxy. The source
counterparts are very red, I-K ~7 suggesting strong Galactic absorption
with additional absorption by the lensing galaxy at z = 0.885, and
consistent with the detection of high redshift molecules in the lens.
---------------------------------------------------------
Title: Abundance correlations in mildly metal-poor stars
Authors: Jehin, E.; Magain, P.; Neuforge, C.; Noels, A.; Parmentier,
G.; Thoul, A. A.
1999A&A...341..241J Altcode: 1998astro.ph..9405J
Accurate relative abundances have been obtained for a sample of 21
mildly metal-poor stars from the analysis of high resolution and
high signal-to-noise spectra. In order to reach the highest coherence
and internal precision, lines with similar dependency on the stellar
atmospheric parameters were selected, and the analysis was carried out
in a strictly differential way within the sample. With these accurate
results, correlations between relative abundances have been searched
for, with a special emphasis on the neutron capture elements. This
analysis shows that the r elements are closely correlated to the
alpha elements, which is in agreement with the generally accepted
idea that the r-process takes place during the explosion of massive
stars. The situation is more complex as far as the s elements are
concerned. Their relation with the alpha elements is not linear. In a
first group of stars, the relative abundance of the s elements increases
only slightly with the alpha elements overabundance until the latter
reaches a maximum value. For the second group, the s elements show a
rather large range of enhancement and a constant (and maximum) value
of the alpha elements overabundance. This peculiar behaviour leads
us to distinguish between two sub-populations of metal-poor stars,
namely Pop IIa (first group) and Pop IIb (second group). We suggest
a scenario of formation of metal-poor stars based on two distinct
phases of chemical enrichment, a first phase essentially consisting
in supernova explosions of massive stars, and a second phase where
the enrichment is provided by stellar winds from intermediate mass
stars. More specifically, we assume that all thick disk and field
halo stars were born in globular clusters, from which they escaped,
either during an early disruption of the cluster (Pop IIa) or, later,
through an evaporation process (Pop IIb). Based on observations obtained
at the European Southern Observatory, La Silla, Chile.
---------------------------------------------------------
Title: Image deconvolution of lensed QSOs observed with the NOT:
Competing with the HST (poster)
Authors: Burud, I.; Courbin, F.; Magain, P.
1999anot.conf..105B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Linking Field Metal-Poor Stars and Globular Clusters: The
Ease Scenario
Authors: Jehin, E.; Magain, P.; Neuforge, C.; Noels, A.; Parmentier,
G.; Thoul, A.
1999gecd.conf..287J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Deep imaging of AXJ2019+112: The luminosity of a “Dark
Cluster”
Authors: Benitez, N.; Broadhurst, T.; Rosati, P.; Courbin, F.; Squires,
G.; Lidman, C.; Magain, P.
1998tx19.confE.504B Altcode:
We detect a distant cluster of galaxies at z ~1 centered on
the QSO lens and luminous X-ray source AXJ2019+112 (Hattori et
al 1997). The mass-to-light ratio within an aperture of 0.4 h
^{-1}Mpc determined using the X-ray temperature is M_x / L_V =
190^{+95}_{-66}h(M/L_V)<SUB>sun</SUB>. The strong lens model yields
a compatible value, M/L_V = 315^{+80}_{-80}h(M/L_V)<SUB>sun</SUB>,
whereas an independent weak lensing analysis sets an upper limit of
M/L_V < 440 h(M/L_V)<SUB>sun</SUB>. This confirms that AXJ2019+112
has a M/L ratio similar to that of z < 1 massive clusters.
---------------------------------------------------------
Title: Three photometric methods tested on ground-based data of
Q 2237+0305
Authors: Burud, I.; Stabell, R.; Magain, P.; Courbin, F.; Ostensen,
R.; Refsdal, S.; Remy, M.; Teuber, J.
1998A&A...339..701B Altcode: 1998astro.ph..9107B
The Einstein Cross, Q 2237+0305, has been photometrically observed in
four bands on two successive nights at NOT (La Palma, Spain) in October
1995. Three independent algorithms have been used to analyse the data:
an automatic image decomposition technique, a CLEAN algorithm and the
new MCS deconvolution code. The photometric and astrometric results
obtained with the three methods are presented. No photometric variations
were found in the four quasar images. Comparison of the photometry from
the three techniques shows that both systematic and random errors affect
each method. When the seeing is worse than 1farcs0 , the errors from the
automatic image decomposition technique and the Clean algorithm tend to
be large (0.04-0.1 magnitudes) while the deconvolution code still gives
accurate results (1sigma error below 0.04) even for frames with seeing
as bad as 1farcs7 . Reddening is observed in the quasar images and is
found to be compatible with either extinction from the lensing galaxy or
colour dependent microlensing. The photometric accuracy depends on the
light distribution used to model the lensing galaxy. In particular,
using a numerical galaxy model, as done with the MCS algorithm,
makes the method less seeing dependent. Another advantage of using
a numerical model is that eventual non-homogeneous structures in the
galaxy can be modeled. Finally, we propose an observational strategy
for a future photometric monitoring of the Einstein Cross. Based on
observations obtained at NOT, La Palma.
---------------------------------------------------------
Title: High-Resolution Optical and Near-Infrared Imaging of the
Quadruple Quasar RX J0911.4+0551
Authors: Burud, I.; Courbin, F.; Lidman, C.; Jaunsen, A. O.; Hjorth,
J.; Østensen, R.; Andersen, M. I.; Clasen, J. W.; Wucknitz, O.;
Meylan, G.; Magain, P.; Stabell, R.; Refsdal, S.
1998ApJ...501L...5B Altcode: 1998astro.ph..3175B
We report the detection of four images in the recently discovered
lensed QSO RX J0911.4+0551. With a maximum angular separation of
3.1", it is the quadruply imaged QSO with the widest known angular
separation. Raw and deconvolved data reveal an elongated lens
galaxy. The observed reddening in at least two of the four QSO images
suggests differential extinction by this lensing galaxy. We show that
both an ellipticity of the galaxy (ɛ<SUB>min</SUB>=0.075) and an
external shear (γ<SUB>min</SUB>=0.15) from a nearby mass have to be
included in the lensing potential in order to reproduce the complex
geometry observed in RX J0911.4+0551. A possible galaxy cluster is
detected about 38" from RX J0911.4+0551 and could contribute to the
X-ray emission observed by ROSAT in this field. The color of these
galaxies indicates a plausible redshift in the range of 0.6-0.8. <P
/>Based on observations obtained at NOT and ESO La Silla.
---------------------------------------------------------
Title: Image Deconvolution of the Radio Ring PKS 1830-211
Authors: Courbin, F.; Lidman, C.; Frye, B. L.; Magain, P.; Broadhurst,
T. J.; Pahre, M. A.; Djorgovski, S. G.
1998ApJ...499L.119C Altcode: 1998astro.ph..2156C
New high-quality Keck and ESO images of PKS 1830-211 are presented. By
applying a powerful new deconvolution algorithm to these optical and
infrared data, both images of the flat spectrum core of the radio
source have been identified. An extended source is also detected in
the optical images which is consistent with the expected location of
the lensing galaxy. The source counterparts are very red at I-K~7,
which suggests strong Galactic absorption with additional absorption
by the lensing galaxy at z=0.885 and is consistent with the detection
of high-redshift molecules in the lens. <P />Based on observations
obtained at the ESO La Silla Observatory, Chile and at the W. M. Keck
Observatory, Hawaii, which is operated jointly by the California
Institute of Technology and the University of California.
---------------------------------------------------------
Title: RX J0911.4+0551: a complex quadruply imaged gravitationally
lensed QSO.
Authors: Burud, I.; Courbin, F.; Lidman, C.; Meylan, G.; Magain, P.;
Jaunsen, A. O.; Hjorth, J.; Østensen, R.; Andersen, M. I.; Clasen,
J. W.; Stabell, R.; Refsdal, S.
1998Msngr..92...29B Altcode:
The authors present their first observations of RX J0911.4+0551 at
the 2.2-m ESO/MPI IRAC 2b in K-band which made them suspect that the
QSO might be quadruple. This was confirmed on the optical data from
the 2.56-m Nordic Optical Telescope, and on the NTT/SOFI data of the
object. Careful deconvolution of the data allows to clearly resolve
the object into four QSO components and a lensing galaxy.
---------------------------------------------------------
Title: Deconvolution with Correct Sampling
Authors: Magain, P.; Courbin, F.; Sohy, S.
1998ApJ...494..472M Altcode: 1997astro.ph..4059M
A new method for improving the resolution of astronomical images
is presented. It is based on the principle that sampled data cannot
be fully deconvolved without violating the sampling theorem. Thus,
the sampled image should be deconvolved not by the total point-spread
function but by a narrower function chosen so that the resolution of
the deconvolved image is compatible with the adopted sampling. <P />Our
deconvolution method gives results that are, in at least some cases,
superior to those of other commonly used techniques: in particular, it
does not produce ringing around point sources superposed on a smooth
background. Moreover, it allows researchers to perform accurate
astrometry and photometry of crowded fields. These improvements
are a consequence of both the correct treatment of sampling and the
recognition that the most probable astronomical image is not a flat
one. <P />The method is also well adapted to the optimal combination
of different images of the same object, as can be obtained, e.g.,
from infrared observations or via adaptive optics techniques.
---------------------------------------------------------
Title: Heavy elements abundances in metal-poor stars
Authors: Magain, P.; Jehin, E.; Neuforge, C.; Noels, A.
1998AIPC..425..592M Altcode:
A sample of 21 metal-poor stars have been analysed on the basis
of high resolution and high signal-to-noise spectra. Correlations
between relative abundances of 16 elements have been studied, with a
special emphasis on the neutron-capture ones. This analysis reveals the
existence of two sub-populations of field halo stars, namely Pop IIa and
Pop IIb. They differ by the behaviour of the s-process elements versus
the α and r-process elements. We suggest a scenario of formation of
these stars, which closely relates the field halo stars to the evolution
of globular clusters. The two sub-populations would have evaporated
the clusters during two different stages of their chemical evolution.
---------------------------------------------------------
Title: Detection of the lensing galaxy in HE 1104-1805
Authors: Courbin, F.; Lidman, C.; Magain, P.
1998A&A...330...57C Altcode: 1997astro.ph..7183C
We report on deep IR imaging of the double quasar HE 1104-1805. A new
image deconvolution technique has been applied to the data in order to
optimally combine the numerous frames obtained. The resulting J and K'
images allow us to detect and study the lensing galaxy between the two
lensed QSO images. The near infrared images not only confirm the lensed
nature of this double quasar, but also support the previous redshift
estimate of z=1.66 for the lensing galaxy. No obvious overdensity of
galaxies is detected in the immediate region surrounding the lens, down
to limiting magnitudes of J=22 and K=20. The geometry of the system,
together with the time delays expected for this lensed quasar, make
HE 1104-1805 a remarkable target for future photometric monitoring
programs, for the study of microlensing and for the determination of
the cosmological parameters in the IR and optical domains. Based on
observations obtained at ESO, La Silla, Chile
---------------------------------------------------------
Title: Field halo stars: the globular cluster connection
Authors: Jehin, E.; Magain, P.; Neuforge, C.; Noels, A.; Thoul, A. A.
1998A&A...330L..33J Altcode:
High resolution and high signal-to-noise spectra of about 20 metal-poor
stars have been analysed. The correlations between the relative
abundances of 16 elements have been studied, with a special emphasis on
the neutron-capture ones. This analysis reveals the existence of two
subpopulations of field halo stars, namely Pop IIa and Pop IIb. They
differ by the behaviour of the s-process elements versus the alpha
and r-process elements. A scenario for the formation of these stars
is presented, which closely relates the origin of field halo stars
to the evolution of globular clusters. According to this scenario,
the two sub-populations originate from two different stages in the
globular cluster's chemical evolution. Based on observations carried
out at the European Southern Observatory (La Silla, Chile)
---------------------------------------------------------
Title: The impact of AGB stars on the chemical evolution of globular
clusters
Authors: Jehin, E.; Magain, P.; Neuforge, C.; Noels, A.; Parmentier,
G.; Thoul, A. A.
1998IAUS..191P.603J Altcode:
We have analyzed high resolution and high signal-to-noise spectra
of about 20 metal-poor stars. The correlations between the relative
abundances of 16 elements have been studied, with a special emphasis on
the neutron-capture ones. This analysis reveals the existence of two
sub-populations of field halo stars, namely Pop IIa and Pop IIb. They
differ by the behaviour of the s-process elements versus the alpha
and r-process elements. We present a scenario for the formation of
these stars, which closely relates the origin of field halo stars
to the evolution of globular clusters. According to this scenario,
the two sub-populations originate from two different stages in the
globular cluster's chemical evolution. In the first stage, the massive
stars of the globular cluster's first stellar generation evolve,
ending their lives as supernovae and ejecting alpha-elements and
r-process elements into the interstellar medium. A second generation
of stars forms out of this enriched ISM. In the second stage, the
intermediate mass stars reach the end of the main sequence and the
AGB stage, ejecting s-elements into the ISM through stellar winds or
superwinds events. The matter released in the ISM by the AGB stars
will be accreted by the lower-mass stars, enriching those stars in
s-elements and accounting for PopIIb stars. We calculate the rates
of interstellar gas production by stellar winds and the rates of
gas accretion to estimate the changes in the globular cluster stars
abundances. We compare those results to our observations.
---------------------------------------------------------
Title: ESO & NOT photometric monitoring of the Cloverleaf quasar
Authors: Ostensen, R.; Remy, M.; Lindblad, P. O.; Refsdal, S.; Stabell,
R.; Surdej, J.; Barthel, P. D.; Emanuelsen, P. I.; Festin, L.; Gosset,
E.; Hainaut, O.; Hakala, P.; Hjelm, M.; Hjorth, J.; Hutsemekers, D.;
Jablonski, M.; Kaas, A. A.; Kristen, H.; Larsson, S.; Magain, P.;
Pettersson, B.; Pospieszalska-Surdej, A.; Smette, A.; Teuber, J.;
Thomsen, B.; van Drom, E.
1997A&AS..126..393O Altcode:
The Cloverleaf quasar, H1413+117, has been photometrically monitored
at ESO (La Silla, Chile) and with the NOT (La Palma, Spain) during the
period 1987--1994. All good quality CCD frames have been successfully
analysed using two independent methods (i.e. an automatic image
decomposition technique and an interactive CLEAN algorithm). The
photometric results from the two methods are found to be very similar,
and they show that the four lensed QSO images vary significantly in
brightness (by up to 0.45 mag), nearly in parallel. The lightcurve of
the $D$ component presents some slight departures from the general trend
which are very likely caused by micro-lensing effects. Upper limits,
at the 99% confidence level, of 150 days on the absolute value for the
time delays between the photometric lightcurves of this quadruply imaged
variable QSO, are derived. This is unfortunately too large to constrain
the lens model but there is little doubt that a better sampling of the
lightcurves should allow to accurately derive these time delays. Pending
a direct detection of the lensing galaxy (position and redshift),
this system thus constitutes another good candidate for a direct and
independent determination of the Hubble parameter. Based on observations
collected at the European Southern Observatory (La Silla, Chile) and
with the Nordic Optical Telescope (La Palma, Spain). Table 1. Logbook
for the ESO and NOT observations together with photometric results for
the Cloverleaf quasar. This long table can be accessed on the WWW at the
URL address: http://vela.astro.ulg.ac.be/grav_lens/glp_homepage.html}
---------------------------------------------------------
Title: Spectroscopic analysis of the Alpha Centauri system
Authors: Neuforge-Verheecke, C.; Magain, P.
1997A&A...328..261N Altcode:
A detailed spectroscopic analysis of the two components of the binary
system alpha Centauri has been carried out on the basis of extensive
high resolution and high signal-to-noise spectra. The temperatures of
the stars have been determined from the Fei excitation equilibrium and
checked from the H_α line wings. The abundances of 17 elements have
been obtained and indicate a general overabundance of 0.24 dex relative
to the Sun, with no significant difference between the two stars. All
elements analysed, from CNO to the iron peak, show basically the same
overabundance. Only nickel seems to be significantly more overabundant,
while the neutron capture elements appear less enhanced. Based on
observations carried out at the European Southern Observatory (La
Silla, Chile)
---------------------------------------------------------
Title: The LMC transition star R 84 and the core of the LH 39 OB
association.
Authors: Heydari-Malayeri, M.; Courbin, F.; Rauw, G.; Esslinger, O.;
Magain, P.
1997A&A...326..143H Altcode: 1997astro.ph..6052H
On the basis of sub-arcsecond imaging obtained at the ESO NTT with
SUSI and the ESO ADONIS adaptive optics system at the 3.6m telescope,
we resolve and study the core components of the LMC OB association LH
39. The central star of the association, the rare transition object
R 84, is also investigated using CASPEC echelle spectroscopy at
the ESO 3.6m telescope. A new, powerful image restoration code that
conserves the fluxes allows us to obtain the magnitudes and colors of
the components. We bring out some 30 stars in a ~16"x16" area centered
on R 84. At a resolution of 0.19"(FWHM), the closest components to R 84
are shown to be stars #21 and #7 lying at 1.1"NW and 1.7"NW respectively
of the transition star. The former is possibly a blue star of V=16.7mag
and the latter with its V=17.5mag is the reddest star of the field,
after R 84. Star #7 turns out to be too faint to correspond to the
red M2 supergiant previously reported to contaminate the spectrum of
R 84. If the late-type spectrum is due to a line-of-sight supergiant
with a luminosity comparable to R 84, it should lie closer than 0.12"
to R 84. The transition star shows spectral variability between 1982
and 1991. We also note some slight radial velocity variations of the Of
emission lines over timescales of several years. Furthermore, we derive
the spectral types of two of the brightest stars of the cluster, using
long slit spectra obtained at the NTT telescope equipped with EMMI,
and discuss the apparent absence of O type stars in this association.
---------------------------------------------------------
Title: The geometry of the quadruply imaged quasar PG 1115+080:
implications for H_0_.
Authors: Courbin, F.; Magain, P.; Keeton, C. R.; Kochanek, C. S.;
Vanderriest, C.; Jaunsen, A. O.; Hjorth, J.
1997A&A...324L...1C Altcode: 1997astro.ph..5093C
Time delay measurements have recently been reported for the lensed
quasar PG 1115+080. These measurements can be used to derive H_0_,
but only if we can constrain the lensing potential. We have applied a
recently developed deconvolution technique to analyze sub-arcsecond I
band images of PG 1115+080, obtained at the Nordic Optical Telescope
(NOT) and the Canada France Hawaii Telescope (CFHT). The high
performance of the deconvolution code allows us to derive precise
positions and magnitudes for the four lensed images of the quasar,
as well as for the lensing galaxy. The new measurement of the galaxy
position improves its precision by a factor of 3 and thus strengthens
the constraints on the lensing potential. With the new data, a range
of models incorporating some of the plausible systematic uncertainties
yields H_0_=53^+10^_-7_km/s/Mpc.
---------------------------------------------------------
Title: VizieR Online Data Catalog: Spectroscopy of Alpha Cen
(Neuforge-Verheecke+ 1997)
Authors: Neuforge-Verheecke, C.; Magain, P.
1997yCat..33280261N Altcode:
This table presents the results of a spectroscopic analysis
(differentially to the Sun) of the two components of the binary system
Alpha Centauri. This analysis has been carried out on the basis of
extensive high resolution and high signal-to-noise spectra taken at
the European Southern Observatory (La Silla, Chile). (1 data file).
---------------------------------------------------------
Title: Deconvolution with correct sampling.
Authors: Magain, P.; Courbin, F.; Sohy, S.
1997Msngr..88...28M Altcode:
The authors briefly describe the basic ideas behind a new deconvolution
technique which overcomes some of the drawbacks of the traditional
methods and which gives results of high photometric and astrometric
accuracy. The authors also show how it can be combined with other
techniques (e.g. adaptive optics) to give even better results.
---------------------------------------------------------
Title: Sub-arcsecond imaging and spectroscopy of the radio-loud
highly polarized quasar PKS 1610-771.
Authors: Courbin, F.; Hutsemekers, D.; Meylan, G.; Magain, P.;
Djorgovski, S. G.
1997A&A...317..656C Altcode: 1996astro.ph..6114C
We report on imaging and spectroscopic observations of the radio-loud,
highly polarized quasar PKS 1610-771 (z=1.71). Our long-slit
spectroscopy of the companion 4.55" NW of the quasar confirms the
stellar nature of this object, so ruling out the previously suspected
gravitationally lensed nature of this system. PKS 1610-771 looks
fuzzy on our sub-arcsecond R and I images and appears located in a
rich environment of faint galaxies. Possible magnification, without
image splitting of the quasar itself, by some of these maybe foreground
galaxies cannot be excluded. The continuum fuzz (made of the closest
two objects, viz. A and D) is elongated in a direction orthogonal
to the E vector of the optical polarization, as in high-redshift
radio-galaxies. The spectrum of PKS 1610-771 appears strongly curved,
in a convex way, with a maximum of intensity at ~7,600Å (2,800AÅ rest
frame), possibly indicating a strong ultraviolet absorption by dust.
---------------------------------------------------------
Title: PKS 1610-771: a highly reddened quasar?
Authors: Courbin, F.; Hutsemékers, D.; Meylan, G.; Magain, P.;
Djorgovski, S. G.
1996Msngr..85...27C Altcode:
No abstract at ADS
---------------------------------------------------------
Title: WR22: the most massive Wolf-Rayet star ever weighed.
Authors: Rauw, G.; Vreux, J. -M.; Gosset, E.; Hutsemekers, D.; Magain,
P.; Rochowicz, K.
1996A&A...306..771R Altcode:
The results of an extensive spectroscopic campaign on the eclipsing
binary WR22 are presented. A new radial velocity curve is deduced for
the WN7 component, allowing us to improve the parameters of the orbit,
formerly determined on the basis of photographic spectra. The high
signal-to-noise ratio of our data also allows the detection of some weak
absorption lines which, for the first time, can definitely be attributed
to the companion. A study of their radial velocities gives a mass ratio
of m_WR_/m_O_=2.78 leading to a minimum mass of 72M<SUB>sun</SUB>_ for
the WN7 star. The companion can be classified as a "late O" (O6.5-O8.5)
star with a luminosity ratio of the system q=L_WR_^y^/L_O_^y^ at 5500A
of about 8. The exceptionally high mass of the WN7 star and its high
hydrogen mass-fraction suggest that WR22 is at the beginning of its
Wolf-Rayet evolution. As a matter of fact, with such a high mass, WR22
most probably is still a hydrogen burning object. Therefore, the WN7
component is much closer to a main sequence O star with a "Wolf-Rayet
clothing" than to the other members of the Wolf-Rayet family, which
are rather highly evolved He-burning descendants of massive progenitors.
---------------------------------------------------------
Title: Chemical composition of solar-type stars
Authors: Neuforge, C.; Magain, P.
1996ASPC..109..695N Altcode: 1996csss....9..695N
No abstract at ADS
---------------------------------------------------------
Title: Empirical study of departures from the excitation equilibrium
of FeI in metal-poor stars.
Authors: Magain, P.; Zhao, G.
1996A&A...305..245M Altcode:
A detailed analysis of neutral iron lines in a sample of 13 metal-poor
dwarfs and subgiants is carried out on the basis of high resolution
spectra obtained with the ESO Coude Echelle Spectrometer. The deduced
iron abundance is found to depend on the excitation potential
of the line used, higher excitation lines generally indicating
higher abundances. This could be caused by departures from the local
thermodynamic equilibrium (LTE) or by temperature inhomogeneities in
the stellar atmospheres. The dependency of this effect on the stellar
atmospheric parameters is investigated. From the comparison of iron
lines with lines of other elements, it is concluded that the low
excitation FeI lines are much more affected than the high excitation
lines. The consequences of these effects for the classical abundance
analyses are examined. It is found that they may explain, at least in
part, some previously reported discrepancies between the results of
different authors.
---------------------------------------------------------
Title: Photometric monitoring (1987 to 1994) of the gravitational
lens candidate UM 425.
Authors: Courbin, F.; Magain, P.; Remy, M.; Smette, A.; Claeskens,
J. F.; Hainaut, O.; Hutsemekers, D.; Meylan, G.; van Drom, E.
1995A&A...303....1C Altcode: 1995astro.ph..4053C
We present the results of a 7 year long photometric monitoring of two
components (A and B) of UM 425, thought to be images, separated by 6.5",
of the same z=1.47 quasar. These components have been imaged through
an R filter in order to obtain their light curves. The photometry was
obtained by simultaneously fitting a stellar two-dimensional profile
on each component. The brightest image (component A, m_R_=15.7) shows a
slow and smooth increase in brightness of 0.2 magnitude in seven years,
while the faintest one (component B, m_R_=20.1) displays an outburst
of 0.4 magnitude which lasts approximately two years. The variation
of component B may be interpreted in two ways, assuming UM 425 is
gravitationally lensed. If it is due to an intrinsic variation of
the quasar, we derive a lower limit of 3 years on the time delay from
the fact that it is not observed in component A. On the other hand,
if it is a microlensing "High Amplification Event", we estimate the
size of the source to be ~10^-3^pc, in agreement with standard models
of AGNs. These observations are consistent with the gravitational lens
interpretation of the object. Furthermore, all the CCD frames obtained
under the best seeing conditions have been co-added, in an attempt to
detect the deflector. The final R image reveals a rich field of faint
galaxies in the magnitude range m_R_~22-24. No obvious deflector,
nor any system of arcs or arclets is detected, down to a limiting
magnitude of m_R_~24.
---------------------------------------------------------
Title: VizieR Online Data Catalog: Fe I in metal-poor stars (Magain+,
1996)
Authors: Magain, P.; Zhao, G.
1995yCat..33050245M Altcode:
A detailed analysis of neutral iron lines in a sample of 13 metal-poor
dwarfs and subgiants is carried out on the basis of high resolution
spectra obtained with the ESO Coude Echelle Spectrometer. The deduced
iron abundance is found to depend on the excitation potential
of the line used, higher excitation lines generally indicating
higher abundances. This could be caused by departures from the local
thermodynamic equilibrium (LTE) or by temperature inhomogeneities in
the stellar atmospheres. The dependency of this effect on the stellar
atmospheric parameters is investigated. From the comparison of iron
lines with lines of other elements, it is concluded that the low
excitation Fe I lines are much more affected than the high excitation
lines. The consequences of these effects for the classical abundance
analyses are examined. It is found that they may explain, at least in
part, some previously reported discrepancies between the results of
different authors. (1 data file).
---------------------------------------------------------
Title: Heavy elements in halo stars: the r/s-process controversy.
Authors: Magain, P.
1995A&A...297..686M Altcode:
It has been suggested by Truran (1981) that rapid neutron captures
(the r-process) dominate the production of heavy elements in very
metal-poor stars. Several spectroscopic works analyzing that hypothesis
are reviewed and rediscussed and it is shown that there is, in fact,
no secure observational evidence in support of Truran's suggestion. A
method to determine the odd-to-even isotopic ratio of barium, and thus
to estimate the relative contributions of the r and s-processes, is
presented. It takes advantage of the hyperfine structure affecting the
spectral lines of the odd isotopes to distinguish them from the even
isotopes. This method, applied to the classical metal-poor subgiant
HD 140283, shows that the barium isotopic ratio in that star is in
agreement with a pure s-process production, and excludes any significant
enhancement of the r-process contribution, in disagreement with previous
works based on elemental abundances.
---------------------------------------------------------
Title: Stellar Atmospheres : The Link between Theory and Observation
Authors: Magain, P.
1995LIACo..32..139M Altcode: 1995sews.book..139M
No abstract at ADS
---------------------------------------------------------
Title: Barium Abundances of 20 Metal Deficient Stars
Authors: Zhao, G.; Magain, P.
1995ASPC...81..574Z Altcode: 1995lahr.conf..574Z
No abstract at ADS
---------------------------------------------------------
Title: A seven year campaign on WR 22
Authors: Rauw, G.; Vreux, J. -M.; Gosset, E.; Hutsemekers, D.; Magain,
P.; Manfroid, J.; Remy, M.; Rochowicz, K.
1995IAUS..163..241R Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Vhrs - the Very High Resolution Spectrograph for the VLT
Authors: Magain, P.; Dekker, H.; Delabre, B.
1995ESOSR..15....1M Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Elemental and Isotopic Abundances in Metal-Poor Stars
Authors: Magain, P.
1995svlt.conf...79M Altcode:
No abstract at ADS
---------------------------------------------------------
Title: WR22 as a core hydrogen-burning Wolf-Rayet star
Authors: Rauw, G.; Vreux, J. M.; Gosset, E.; Hutsemekers, D.;
Magain, P.
1995LIACo..32..463R Altcode: 1995sews.book..463R
The analysis of an extensive sample of high resolution spectra of
the Wolf-Rayet binary WR22 recently allowed us to determine a minimum
mass of 72 M_solar for the WN7 star. With such a high mass, WR22 is
expected to be a core H-Burning star which has just evolved from a
progenitor of at least 90-110 M_solar.
---------------------------------------------------------
Title: VHRS: the Very High Resolution Spectrograph for the VLT.
Authors: Magain, P.; Dekker, H.; Delabre, B.
1994fvlt.conf...37M Altcode:
No abstract at ADS
---------------------------------------------------------
Title: (Erratum) Further observational evidence that MG J0414+0534
is a gravitational mirage.
Authors: Angonin-Willaime, M. -C.; Vanderriest, C.; Hammer, F.;
Magain, P.
1994A&A...292..722A Altcode:
In Sect. 3.3, the identifications of components A1 and A2 for
the optical data were inadvertently inverted. This does not change
substantially the discussion; just read A1 for A2 and vice versa. In
particular, the ratio A2/A1 = 0.3 cannot be made compatible with the
radio value without one or several of the mechanisms we suggested. We
apologize for the error and thank Dr S. Mao for bringing it to our
attention. Erratum to Astron. Astrophys. 281, 388-394 (1994)
---------------------------------------------------------
Title: Further observational evidence that MG J0414+0534 is a
gravitational mirage.
Authors: Angonin-Willaime, M. -C.; Vanderriest, C.; Hammer, F.;
Magain, P.
1994A&A...281..388A Altcode:
Deep imaging of MG J0414+0534 with R and I filters reveals a faint,
fuzzy and red object at the exact location expected for a lensing
galaxy in the gravitational mirage hypothesis. Furthermore, the
(extremely red and almost featureless) spectra of the 2 brightest
components are very similar. These are strong indications that
the system results from multiple gravitational imaging of a single
source, but the nature of this source is not yet clear. It could
be the nucleus of a low metallicity galaxy at a high redshift or a
new type of object. Significant differences are observed between the
flux ratios of the images at radio and optical wavelengths. The most
likely explanation for this effect is a differential amplification of
the image pair A_1_-A_2_ because of the large magnification gradient
near a caustic.
---------------------------------------------------------
Title: On the linearity of ESO CCD#9 at CAT+CES.
Authors: Gosset, E.; Magain, P.
1993Msngr..73...13G Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Gravitational Lensing Statistics Based on a Large Sample of
Highly Luminous Quasars
Authors: Surdej, J.; Claeskens, J. F.; Crampton, D.; Filippenko,
A. V.; Hutsemekers, D.; Magain, P.; Pirenne, B.; Vanderriest, C.;
Yee, H. K. C.
1993AJ....105.2064S Altcode:
Results on gravitational lensing statistics applied to a sample of 469
highly luminous quasars are reported. The objects were directly imaged,
either from the ground (ESO, CFH) under optimal seeing conditions,
or using the Hubble Space Telescope. We have derived values for the
effectiveness parameter F of galaxies, modeled by means of singular
isothermal spheres, to produce macrolensed images of distant quasars,
and upper limits on the density parameter {OMEGA}_L_ of compact objects
with masses ~10^10^ - 10^12^ M_sun_. Adopting H_0_ = 50 km/s/Mpc,
{OMEGA}_0_= 1 and λ = 0, we find that at the 99.7% confidence level,
0.005 < F < 0.478 and that {OMEGA}_L_ < 0.02. A critical
discussion of these results is presented. Finally, comparing the
efficiencies of ground-based and space instruments used to search for
gravitational lens systems among highly luminous quasars, we conclude
that for the near future, ground based direct imaging characterized by a
good dynamical range still constitutes the best observational strategy.
---------------------------------------------------------
Title: Erratum - Q:1208+1011 - the Most Distant Multiply Imaged
Quasar or a Binary
Authors: Magain, P.; Surdej, J.; Vanderriest, C.; Pirenne, B.;
Hutsemekers, D.
1993A&A...272..383M Altcode:
In the title of this Letter, the word "multiply" was accidentally
omitted. The correct title is shown above.
---------------------------------------------------------
Title: Barium isotopes in the very metal-poor star HD 140283.
Authors: Magain, P.; Zhao, G.
1993A&A...268L..27M Altcode:
The fractions of odd and even isotopes of barium in the metal-poor
star HD140283 are determined from an analysis of the profile of the
Ba II resonance line, taking advantage of the differences in hyperfine
structure splitting between the different isotopes. Although one would
expect an increased contribution of the r-process in very metal-poor
stars, it is found that the isotopic ratio is very close to solar.
---------------------------------------------------------
Title: Search for gravitational lenses in a large sample of highly
luminous quasars and statistical determination of cosmological
parameters
Authors: Claeskens, J. F.; Crampton, D.; Filippenko, A. V.;
Hutsemekers, D.; Magain, P.; Pirenne, B.; Surdej, J.; Vanderriest,
C.; Yee, H. K. C.
1993LIACo..31..263C Altcode: 1993glu..conf..263C
Results on gravitational lensing statistics applied to a sample of
469 highly luminous quasars are reported.
---------------------------------------------------------
Title: Barium isotopes in metal-poor stars.
Authors: Magain, P.; Zhao, G.
1993oee..conf..480M Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Coincidences
Authors: Magain, P.; Remy, M.
1993LIACo..31..137M Altcode: 1993glu..conf..137M
No abstract at ADS
---------------------------------------------------------
Title: Two new very close pairs of quasars with discordant redshifts
and a gravitational lens candidate.
Authors: Surdej, J.; Remy, M.; Smette, A.; Claeskens, J. -F.; Magain,
P.; Refsdal, S.; Swings, J. -P.; Veron-Cetty, M.
1993Lie93..31..153S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The cloverleaf quasar H1413+117: a preliminary light curve
Authors: Arnould, P.; Remy, M.; Gosset, E.; Hainaut, O.; Hutsemekers,
D.; Magain, P.; Smette, A.; Surdej, J.; van Drom, E.
1993LIACo..31..169A Altcode: 1993glu..conf..169A
The cloverleaf quasar H1413+117 was discovered to be a gravitational
lens system in 1988. Since then, it has been photometrically monitored
essentially as part of the ESO key-program Gravitational lensing: we
present here a first preliminary lightcurve for its four individual
images.
---------------------------------------------------------
Title: Galaxies statistics around highly luminous quasars: the
ESO Sample
Authors: van Drom, E.; Surdej, J.; Magain, P.; Hutsemekers, D.;
Gosset, E.; Claeskens, J. F.; Shaver, P.; Melnick, J.
1993LIACo..31..301V Altcode: 1993glu..conf..301V
We present observational evidence on the correlation between the
positions of Highly Luminous Quasars and those of galaxies for a sample
of 136 objects, observed under good seeing conditions.
---------------------------------------------------------
Title: The relative photometric lightcurve of UM673 A&B
Authors: Daulie, G.; Hainaut, O.; Hutsemekers, D.; Magain, P.; Remy,
M.; Smette, A.; Surdej, J.; van Drom, E.
1993LIACo..31..181D Altcode: 1993glu..conf..181D
From 1987 to 1993, we have carried out at ESO a photometric monitoring
of the gravitationally lensed quasar UM673. The main result is that
the two lensed images of UM673 did not show any significant relative
variation during more than five years.
---------------------------------------------------------
Title: ESO key programme, gravitational lensing: quasars and radio
galaxies; a status report
Authors: Surdej, J.; Angonin, M. C.; Arnaud, J.; Bauer, T.; Borgeest,
U.; Hainaut, O.; Hammer, F.; Hutsemekers, D.; Le Fevre, O.; Nottale,
L.; Magain, P.; Meylan, G.; Remy, M.; Shaver, P.; Smette, A.; Swings,
J. P.; van Drom, E.; Veron-Cetty, M.; Veron, P.
1992daec.conf...97S Altcode:
The scientific background and objectives of our ESO Key Programme are
first recalled. A brief account of our research activities (observing
runs at ESO and elsewhere, meetings, etc.) is then given. Preliminary
scientific results are presented concerning 1) our observational
database for highly luminous quasars and distant powerful radiogalaxies;
2) speckle observations of highly luminous quasars; 3) the photometric
monitoring and 4) detailed studies of several known gravitational
lenses; 5) optical observations of 3C and 4C radio galaxies and 6)
of the well known Einstein ring MG 1131+0456.
---------------------------------------------------------
Title: A Spectroscopic Study of UM 673 A and B: On the Size of
Lyman-Alpha Clouds
Authors: Smette, A.; Surdej, J.; Shaver, P. A.; Foltz, C. B.; Chaffee,
F. H.; Weymann, R. J.; Williams, R. E.; Magain, P.
1992ApJ...389...39S Altcode:
We present a study of the Lyα forest spectra (2 A resolution) obtained
for the A and B images of the gravitationally lensed high- redshift
quasar UM 673. We also present higher resolution data of the brightest
(A) image. In the 2 A resolution spectra, all the absorption lines
detected at 5 σ in the spectrum of the fainter B image are present in
the A image; however, we find two anticoincidences, i.e., two lines in
A which do not have a counterpart in B at more than a 3 σ confidence
level. Given the fact that corresponding Lyα lines in the spectra of
A and B have their equivalent widths well correlated, this proves that
both light beams actually cross the same clouds. Most of the velocity
differences between corresponding lines are compatible with 0 km s^-1^
within the error bars, with a standard deviation of 17 km s^-1^. As
the comoving linear separation increases from virtually 0h^-1^_50_ kpc
(H_0_ = 50h_50_ km s^-1^ Mpc^-1^, q_0_ = 0) at the redshift of the QSO
to 2h^-1^_50_ kpc, we derive a best value of 12h^-1^_50_1 kpc for the
2 σ lower limit and of 160h^-1^_50_ kpc for the 2 σ upper limit of
the diameter of spherical Lyα clouds in the redshift range 2.1-2.7,
by means of Monte Carlo simulations. However, if we interpret the two
anticoincidences as due to a Mg II doublet at z = 0.4261, we find in
this case a best value of 23h^-1^_50_ kpc to the 2 σ lower limit of
the Lyα cloud diameter, but we cannot derive any upper limit. For the
two major heavy-element systems detected in the spectrum of UM 673,
we do not find any significant difference between the corresponding
lines in the two spectra, indicating that these systems do not show
dramatic variations over scales of 0.8h^-1^_50_ and 2.1h^-1^_50_
kpc, respectively.
---------------------------------------------------------
Title: The new gravitational lens candidate Q 1208+1011 and the
importance of high quality data.
Authors: Magain, P.; Surdej, J.; Vanderriest, C.; Pirenne, B.;
Hutsemékers, D.
1992Msngr..67...30M Altcode: 1992Mgr....67...30M
No abstract at ADS
---------------------------------------------------------
Title: Using the HST Archive - gravitational lenses from the
Snapshop Survey
Authors: Pirenne, B.; Surdej, J.; Magain, P.
1992STECF..17...22P Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Search for gravitational lensing in a sample of highly
luminous quasars
Authors: Magain, P.; Hutsemekers, D.; Surdej, J.; Vandrom, E.
1992LNP...406...88M Altcode: 1992grle.conf...88M
The status of the ESO survey for gravitational lensing among highly
luminous quasars (HLQs) is briefly reviewed. The statistics of lensing,
both concerning the multiple images and the associations of galaxies
with quasars, are examined. We find a significant overdensity of
galaxies very close to the line-of-sight to the HLQs. We also report
the discovery of a new multiply lensed quasar candidate.
---------------------------------------------------------
Title: Magain P., Surdej J., Vanderriest C., Pirenne B., Hutsemekers
Authors: Magain, P.; Surdej, J.; Vanderriest, C.; Pirenne, B.;
Hutsemekers, D.
1992A&A...253L..13M Altcode:
We report the discovery of a new gravitational lens candidate: the
high redshift (z = 3.803) and highly luminous (V = 17.5, M_V_ = - 30.3)
quasar Q 1208+1011. As derived from the analysis of direct CCD frames
taken with the ESO/MPI 2.2m telescope, this multiple quasar consists
of two point-like images, separated by 0.45" and characterized by a
brightness ratio of 3.5, in red light. Existing spectroscopic data
support the gravitational lens interpretation for this system but
cannot exclude the hypothesis of a binary quasar. In the former case,
the spectrum suggests that, if the metallic absorption line system
reported by Steidel (1990) at a redshift z = 2.9157 is associated
with the deflector, the mass of the lens should be of the order of M
= 7.8 10^11^M_sun_(q_0_ = 0, H_0_ = 50 km s^-1^ Mpc^-1^). Evaluation
of a recent HST PC frame obtained for Q 1208+1011 within the snapshot
survey for gravitational lenses confirms the above results.
---------------------------------------------------------
Title: Gravitational lensing statistics based on a large sample of
highly luminous quasars observed with ground-based telescopes and HST
Authors: Surdej, J.; Claeskens, J. F.; Crampton, D.; Filippenko,
A. V.; Hutsemekers, D.; Magain, P.; Pirenne, B.; Vanderriest, C.;
Yee, H. K. C.
1992ESOC...44..111S Altcode: 1992swhs.conf..111S
We present here some recent results on gravitational lensing statistics
as applied to a sample of 470 highly luminous quasars.
---------------------------------------------------------
Title: Optical observations of gravitational lenses
Authors: Surdej, J.; Claeskens, J. F.; Hutsemekers, D.; Magain, P.;
Pirenne, B.
1992LNP...406...27S Altcode: 1992grle.conf...27S
We report here on some of the major developments achieved on optical
observations of gravitational lenses since the last conference devoted
to 'Gravitational Lensing'.
---------------------------------------------------------
Title: Calibration of the alpha Centauri system : metallicity and age.
Authors: Noels, A.; Grevesse, N.; Magain, P.; Neuforge, C.; Baglin,
A.; Lebreton, Y.
1991A&A...247...91N Altcode:
The binary system Alpha Cen A and B, with its well known parallax,
its high quality orbit and the reasonable hypothesis of a common
origin and age for both components, is a useful test of stellar
evolution models. Evolutionary sequences are computed for 1.085
and 0.9 solar masses with different values of Z, Y and alpha (=
l/Hp). Adopting luminosities and effective temperatures as derived from
the observations, Z = 0.04, Y = 0.32, alpha = 1.6 and t = 5 Gyr. The
Z-value derived from evolutionary sequences is very sensitive to the
difference in effective temperature between the two components.
---------------------------------------------------------
Title: Abundances of neutron capture elements in metal-poor dwarfs. I
Yttrium and zirconium.
Authors: Zhao, G.; Magain, P.
1991A&A...244..425Z Altcode:
The yttrium and zirconium abundances are determined in a sample
of 20 metal-poor stars on the basis of high resolution, high SNR
spectra. Significant differences between the behaviors of these two
neighboring elements are found, zirconium being less deficient than
yttrium in Population II stars. Moreover, there is a genuine cosmic
scatter in the abundances of these two elements relative to iron, of
the order of 20 percent. The scatter is lower when these elements are
compared to titanium, which might indicate that a significant fraction
of the lighter neutron-capture elements are produced in massive stars.
---------------------------------------------------------
Title: A Spectroscopic Study of UM673 A &B: on the size of Lyman-
αClouds
Authors: Smette, A.; Surdej, J.; Shaver, P. A.; Foltz, C. B.; Chaffee,
F. H.; Weymann, R. J.; Williams, R. E.; Magain, P.
1991qal..work...37S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Miscellaneous spectroscopic observations of quasars and
quasar candidates.
Authors: Veron, P.; Veron-Cetty, M. -P.; Djorgovski, S.; Magain, P.;
Meylan, G.; Surdej, J.
1990A&AS...86..543V Altcode:
We report about new spectroscopic observations of 11 quasar candidates,
19 quasars with uncertain redshift and three BL Lac candidates, and
11 objects located within few arcseconds from a quasar.
---------------------------------------------------------
Title: The chemical composition ofthe extreme halo
stars. III. Equivalent widths of 20.
Authors: Zhao, G.; Magain, P.
1990A&AS...86...85Z Altcode:
In the first two papers of this series the chemical composition of
20 extreme halo stars was discussed. The abundances of a number of
elements were determined using model atmosphere analysis of equivalent
widths. In this paper a tabulation of the equivalent width data is
presented. A comparison of the measurements with the equivalent widths
from different sources is used to assess the quality of the data.
---------------------------------------------------------
Title: New Observations and Gravitational Lens Models of the
Cloverleaf Quasar H1413+117
Authors: Kayser, R.; Surdej, J.; Condon, J. J.; Kellermann, K. I.;
Magain, P.; Remy, M.; Smette, A.
1990ApJ...364...15K Altcode:
New optical and radio observations of the quadruple quasar H1413 + 117,
the Cloverleaf, carried out with the 1.54 m Danish telescope at ESO
and with the VLA at NRAO are presented. The VLA data, obtained in the
A configuration at 3.6 cm, show radio counterparts at the positions of
the four optical images and an additional strong radio source between
images B and D. Gravitational lens models of H1413 + 117 using (a) a
single elliptical galaxy and (b) two spherical galaxies are presented,
which fit the positions of the four images of the quasar remarkably
well. The models suggest that the strong radio source is a feature of
the quasar, e.g., an ejected blob, which lies right on the caustic of
the lens and is thereby strongly amplified. The time delays predicted
by our models are sufficiently short to allow for their determination
within one observational season, making H1413 + 117 an exceptionally
well suited object for gravitational lens research.
---------------------------------------------------------
Title: Core velocity dispersion and mass-to-light ratio of the old
Magellanicglobular cluster NGC 1835.
Authors: Dubath, P.; Meylan, G.; Mayor, M.; Magain, P.
1990A&A...239..142D Altcode:
The projected velocity dispersion in the core of the old Large
Magellanic Cloud globular cluster NGC 1835 is deduced from integrated
light spectra obtained at the European Southern Observatory (ESO)
with CASPEC, the Cassegrain ESO Echelle Spectrograph mounted on the
ESO 3.6-m telescope at La Silla, Chile. A numerical cross-correlation
technique gives a projected velocity dispersion σ_p_(core) = 10.1 + 0.2
km s^-1^. Multimass anisotropic King-Michie dynamical models are applied
to the observational constraints given by the surface brightness profile
and the above central projected velocity dispersion. Depending on the
model, the values obtained for the total mass of the cluster range
from 0.70 to 1.55 10^6^ M_sun_, with a mean total mass <M_tot_>
= 1.0 +/- 0.3 10^6^ M_sun_, corresponding to a global mass-to-light
ratio <M/L_V_> = 3.4 +/- 1.0 (M/L_V_). The present study
shows that when the same kind of dynamical models (King-Michie)
constrained by the same kind of observations (surface brightness
profile and central value of the projected velocity dispersion) are
applied to an old rich Magellanic globular cluster, viz., NGC 1835,
the results seem similar to those obtained in the case of galactic
globular clusters. Consequently, the rich old globular clusters in
the Magellanic clouds could be quite similar (in mass and M/L_V_)
to the rich globular clusters in the Galaxy.
---------------------------------------------------------
Title: The chemical composition of the extreme halo stars. II. Green
spectra of 20 dwarfs.
Authors: Zhao, G.; Magain, P.
1990A&A...238..242Z Altcode:
The abundances of nine elements in the atmospheres of 20 extreme
metal-poor stars are derived from green spectra obtained with the
ESO Cassegrain Echelle Spectrograph (CASPEC). Sodium is found to be
overabundant with respect to aluminum by as much as one dex. There
is some scatter in Ca/Fe which cannot be accounted for by random
errors in equivalent widths or atmospheric parameters. Scandium is
overabundant relative to iron. Some barium lines may be affected
by strong departures from local thermodynamic equilibrium. The
nitrogen-rich metal-poor star HD 74000, which was found in previous
work to be also Al-rich, also presents higher than usual abundances
of Na and of s-process elements. It can thus be considered as a mild
barium dwarf of Population II.
---------------------------------------------------------
Title: High-Resolution Spectroscopy of the C 2 Swan 0--0 Band from
Comet P/Halley
Authors: Lambert, D. L.; Sheffer, Y.; Danks, A. C.; Arpigny, C.;
Magain, P.
1990ApJ...353..640L Altcode:
High-resolution spectra of the C2 Swan system's 0-0 band from Comet
P/Halley in March 1986 show that the populations of the upper state's
rotational levels may be described by two rotational temperatures. The
low rotational levels provide a low temperature, Trot = about 600 -
700 K. The higher levels correspond to about 3200 K. If a contribution
from the 3200-K molecules is subtracted from the populations of the
low-J-prime levels, the latter are characterized by Trot = about 190
K. A comparison with recent predictions for C2 molecules fluorescing
in sunlight shows that the observed and predicted level populations
are in good agreement for J-prime greater than about 15, but there is
a sharp disagreement for the low rotational levels.
---------------------------------------------------------
Title: A search for gravitational lensing among highly luminous
quasars : observational strategy and survey
Authors: Swings, J. P.; Magain, P.; Remy, M.; Surdej, J.; Smette,
A.; Hutsemekers, D.; van Drom, E.
1990LNP...360...83S Altcode: 1990grle.work...83S
The observational technique used for our search for gravitational
mirages is presented : recent results, as well as future observations,
are outlined.
---------------------------------------------------------
Title: Preliminary analysis of high-resolution spectra for UM 673
A & B
Authors: Smette, A.; Surdej, J.; Shaver, P. A.; Foltz, C. B.; Chaffee,
F. H., Jr.; Magain, P.
1990LNP...360..122S Altcode: 1990grle.work..122S
No abstract at ADS
---------------------------------------------------------
Title: A Search for Gravitational Lensing Among Highly Luminous
Quasars: New Results
Authors: Magain, P.; Remy, M.; Surdej, J.; Swings, J. -P.; Smette, A.
1990LNP...360...88M Altcode: 1990grle.work...88M
Images of highly luminous QSOs are analyzed to determine whether
the gravitational magnification of the background QSO by matter
associated with the foreground galaxies accounts for the excess of
galaxies in the fields of distant QSOs. Galaxy detection is increased
by utilizing red-filter images, 40 taken with the EFOSC at the ESO
3.6-m telescope and 43 taken with a direct CCD camera at the ESO/MPI
2.2-m telescope. The R-magnitude ranges from 22.5 to 23.0 for the
sample, for which the number of galaxies is counted by eye, showing
45 galaxies of radio and optical type. The overdensity found is not as
pronounced as that of Fugmann (1988) or that of Webster et al. (1988). A
systematic subtraction of the point spread function is also described to
investigate the idea that some galaxies responsible for the QSO light
magnification are within the inner 3-arcsec circle. The galaxies very
close to the line-of-sight are theorized to contribute significantly
to the magnification of these QSOs.
---------------------------------------------------------
Title: Two more very massive stars resolved.
Authors: Heydari-Malayeri, M.; Magain, P.; Remy, M.
1989A&A...222...41H Altcode:
We present new evidence against the existence of very massive stars in
the Magellanic Clouds. Using high resolution CCD images and appropriate
image restoration methods, we show that Sk 157 and Sk-69^deg^253
(Sanduleak, 1968, 1969), lying in the SMC and LMC respectively, are
not single, very massive, but multiple systems. Thus, two of the most
massive stars in existence, with the estimated masses of ~ 85 _sun_
and > 120 M_sun_, vanish from astronomy. The results presented
here have important implications for star formation models and the
extragalactic distance scale.
---------------------------------------------------------
Title: A study of the interstellar medium in line to NGC 5128 from
high resolution observations of the supernova 1986G.
Authors: D'Odorico, S.; di Serego Alighieri, S.; Pettini, M.; Magain,
P.; Nissen, P. E.; Panagia, N.
1989A&A...215...21D Altcode: 1989A&A...215...21O
We present new high resolution, high S/N ratio spectra of supernova
1986G in NGC 5128 (Cen A). These data allow a detailed study of the
rich interstellar absorption spectrum originating in the line of sight
to the SN. At least 12 distinct Ca II and Na I absorbing clouds are
identified. The gas associated with NGC 5128 is spread over a velocity
range of 178 km s^-1^ and it is split in at least 7 components. A
new result unique to NGC 5128 is the presence of 3 components with
Ca^+^/Na^0^ column densities ratios smaller than 1, that is typical
of cool disc gas. This is interpreted as a further indication of the
existence of an extended warped disc or a ring of cool gas. From the
discussion of the velocities of the absorption components seen in its
spectrum it is inferred that the SN was at least half way within the
dust and gaseous disc of the galaxy. An intriguing result of this work
is the discovery of two absorption components at v_H_ = 236 and 257 km
s^-1^, which cannot be easily explained within the velocity field of
either the Galaxy or NGC 5128, and may be related to high velocity
clouds of neutral hydrogen observed at nearby lines of sight. We
detected and measured several diffuse interstellar bands at galactic
and NGC 5128 velocities. This is the first time that such a detailed
study has been done in a galaxy beyond the Magellanic Cloud. At NGC 5128
velocities, we also detected, for the first time beyond the Local Group,
molecular absorption lines of CH and CH^+^ at optical wavelengths.
---------------------------------------------------------
Title: What is the mass-to-light ratio of the old Magellanic globular
cluster NGC 1835?
Authors: Meylan, G.; Dubath, P.; Mayor, M.; Magain, P.
1989Msngr..55...55M Altcode: 1989Mgr....55...55M
We astronomers are lucky: our Galaxy as two companion galaxies, the
Large and Small Magellanic Clouds, situated weil above the galactic
plane, which Contain a huge potential of astrophysical information. For
example, concern: ng star clusters, the realm of the globuar clusters
is much richer and more Varied in the Magellanic Clouds than in the
Galaxy: rich clusters of all ages are observed, from the youngest,
having ages of a few tens 10^6 yr to the oldest 1haV'lng ages of the
order"or larger than 10 10^9 yr. In this paper, only old Magellanic
and galactic globular clusters are considered.
---------------------------------------------------------
Title: Absolute dimensions of eclipsing binaries. XIV. UX Mensae.
Authors: Andersen, J.; Clausen, J. V.; Magain, P.
1989A&A...211..346A Altcode:
Spectroscopic orbits are determined for the 4-day, F8 V eclipsing binary
UX Mensae. The masses of the binary components are 1.24 and 1.20 solar
masses with errors of + or - 0.5 percent. The results of the analysis of
the uvby light curves by Clausen and Gronbech (1976) are confirmed. The
metal abundance is found to be Fe/H = +0.04 + or - 0.10. Absolute
dimensions are computed for the binary. Theoretical evolutionary
sequences for the masses and metal abundance are interpolated from
the models of VandenBerg (1988) and Andersen et al. (1988).
---------------------------------------------------------
Title: IRC +10216: a peanut nebula!
Authors: Le Bertre, T.; Magain, P.; Remy, M.
1989Msngr..55...25L Altcode:
Carbon stars with low effective temperature (2,000-3,000 K) are thought
to be long-period variables evolving on the Asymptotic Giant Branch
(AGB). These objects are burning alternately hydrogen and helium
in different shells around a degenerate core of carbon and oxygen
[1]. Material processed during the helium burning phase is dredged-up by
convection to the surface and enriches it in carbon relative to oxygen.
---------------------------------------------------------
Title: Profiles of a Key Programme: Gravitational Lensing
Authors: Surdej, J.; Arnaud, J.; Borgeest, U.; Djorgovski, S.;
Fleischmann, F.; Hammer, F.; Hutsemekers, D.; Kayser, R.; Le Fevre,
O.; Nottale, L.; Magain, P.; Meylan, G.; Refsdal, S.; Remy, M.;
Shaver, P.; Smette, A.; Swings, J. P.; Vanderriest, C.; van Drom,
E.; Véron-Cetty, M.; Véron, P.; Weigelt, G.
1989Msngr..55....8S Altcode: 1989Mgr....55....8S
Prior to Professor van der Laan's enquiry, in the March 1988 issue
of the Messenger, on the general interest among astronomers from the
European community to possibly participate in Key Programmes (KPs)
at the European 80uthern Observatory, at least three distinct groups
(including more than half of the above authors) were already involved
in the study of "gravitational lensing" effects (see box on pages
10-11). Observations were being performed with the help of various
telescopes on La 8illa as weil as at other observatories (VLA, CFHT,
Palomar, Kitt Peak, etc.).
---------------------------------------------------------
Title: Core Velocity Dispersion of the LMC Globular Cluster NGC 1835
Authors: Meylan, G.; Dubath, P.; Mayor, M.; Magain, P.
1989BAAS...21..711M Altcode:
No abstract at ADS
---------------------------------------------------------
Title: A Simple Deconvolution Algorithm
Authors: Magain, P.
1989ESOC...31..205M Altcode: 1989daan.work..205M
A very simple image deconvolution algorithm is described in three
cases. It is first established in the case of noise-free data. Then, a
method for taking noise into account is presented. Finally, a smoothing
constraint is included in the algorithm.
---------------------------------------------------------
Title: The chemical composition of the extreme halo stars. I. Blue
spectra of 20 dwarfs
Authors: Magain, P.
1989A&A...209..211M Altcode:
Spectra obtained with the ESO Cassegrain echelle spectrograph are
used to determine the abundances of 13 elements in the atmospheres of
20 extreme halo dwarfs. It is found that the alpha elements Mg, Ca,
and Ti are overabundant with respect to Fe, that the Cr/Fe ratio is
solar at all metallicities, and that Al is overdeficient relative to
Mg. The results also indicate that the s elements Sr, Y, and Ba are
overdeficient with respect to Fe in stars with Fe/H ratios of less
than 2.3, and that for ratios greater than 2.3 the s element abundances
relative to Fe are roughly constant (at either solar or higher values).
---------------------------------------------------------
Title: New evidence against the existence of very massive stars.
Authors: Heydari-Malayeri, M.; Magain, P.; Remy, M.
1988A&A...201L..41H Altcode:
The most luminous stars are our first probes for exploring the
stellar content of distant galaxies. They have also been used as
standard candles for extragalactic distance determinations. We
show that Sk-66^deg^ 41, one of the brightest stars in the Large
Magellanic Cloud (LMC), is a multiple system consisting of at least six
components. This result has important consequences for the understanding
of star formation mechanisms, especially the upper limit to stellar
masses. Moreover, when primary distance indicators are not available,
care should be taken in using the brightest blue stars. The derived
distances, depending on the number of cluster members, can easily be
underestimated by more than a factor 2, leading to larger values for
the Hubble constant.
---------------------------------------------------------
Title: Discovery of a quadruply lensed quasar: the 'clover leaf
H1413 + 117
Authors: Magain, P.; Surdej, J.; Swings, J. -P.; Borgeest, U.;
Kayser, R.
1988Natur.334..325M Altcode: 1988Nat...334..325M
In November 1986 we began an optical search for examples of
gravitational lensing in a sample of highly luminous quasars (HLQs,
M<SUB>v</SUB> < -29), with the aims of improving our knowledge of
the quasar luminosity function, studying the dark matter content of the
Universe, and redetermining some important cosmological parameters. This
survey has found one new case of lensing<SUP>1,2</SUP> and the general
implications of the search have been summarized<SUP>3</SUP>. Here we
report the discovery of a second gravitational lens system in the
broad absorption line quasar H1413 + 117 (refs 4-6). Four images
of comparable brightness are seen, separated by ~1 arcsec. Spectra
obtained of two of the images are identical apart from the presence
of sharp absorption lines in one component, which are presumably due
to gas clouds along the line of sight. The unique configuration of
the images, together with the fairly rare occurrence of this type of
quasar, makes it incontrovertible that this is a lensed system, not a
cluster of quasars, and this second discovery made by imaging bright
quasars establishes the power of the method for finding systems with
small separations.
---------------------------------------------------------
Title: Observations of the new gravitational lens system UM 673 =
Q 0142-100.
Authors: Surdej, J.; Magain, P.; Swings, J. -P.; Borgeest, U.;
Courvoisier, T. J. -L.; Kayer, R.; Kellermann, K. I.; Kuhr, H.;
Refsdal, S.
1988A&A...198...49S Altcode:
In order to better understand the effects of gravitational lensing
on the observed quasar luminosity function, on the source counts
of extragalactic objects, etc., we have recently initiated a high
resolution direct imaging survey of a selected sample of Highly
Luminous Quasars (HLQs). The observations are being carried out
with the 2.2 m telescope at ESO, and with the VLA at the NRAO, New
Mexico. Following a first observing run at ESO, we have reported the
discovery of a new gravitational lens system for the HLQ UM 673 =
Q0142-100. Additional observations supporting this interpretation
are discussed here. We confirm that UM 673 is resolved into two
quasi-stellar images A(m_V_=17.0) and B(m_V_=19.1) separated by 2.22"
and having essentially the same redshift (z_e_=2.719 with z_e_(A)-
z_e_(B)=-0.0002 +/-0.0008). Their emission (Lyα, N V, Si IV, C IV,
etc.) as well as absorption (including a high ionization system at
z_a_=2.3564) line spectra also appear to be quite identical. Further
evidence for the presence of a lensing galaxy (m_R_=19, z_g_=0.49)
between the two QSO images is given by the detection of faint absorption
lines due to Ca II H and K, and possibly Na I D1 and D2, at a redshift
z=0.493 in the spectrum of UM 673 B. Application of gravitational
optometry to this system is given in the present article: a value of
M_0_ = 2.4 10^11^ M_sun_ is derived for the mass of the lensing galaxy
located between UM 673 A and B and a most likely estimate of {DELTA}t =
7 weeks is found for the expected delay between the arrival times of
a similar variability event in the two lensed images of the quasar
(H_0_=75 km s^-1^ Mpc^-1^, q_0_=0). A VLA observation of UM 673 has
been obtained at 6 cm in the hybrid C/D-array configuration. This
radio map indicates the presence of a faint elongated structure which
is possibly associated with the UM 673 gravitational lens system.
---------------------------------------------------------
Title: The SMC compact blob N 81 : a detailed multi-wavelength
investigation.
Authors: Heydari-Malayeri, M.; Le Bertre, T.; Magain, P.
1988A&A...195..230H Altcode:
This paper is devoted to an extensive investigation of the compact Small
Magellanic Cloud H II region N81. Several observational techniques with
various telescopes at ESO have been employed to acquire a multi-aspect
view of the physical characteristics of this interesting nebula:
CCD, IDS and Reticon high, medium and low resolution spectroscopy
(range 3700-10000 A), CCD imaging using 17 different filters,
optical and infrared photometry at UBVRI and JHK. We also use the H I
emission observations reported in the literature. The nebula N81 is
probably excited by one star of about 60 M_sun_, (T_eff_ = 47500 K)
accompanied by a cluster of about 10 B0 stars (M = 15 M_sun_, T_eff_
= 32000 K). We derive the absolute visual magnitude of the exciting
star to be -5.1, corresponding to a bolometric magnitude of M_bol_=
-9.1 and a luminosity of 3.5 10^5^ L_sun_. This nebula is a young H II
region. From the equivalent width of the Hβ emission line we derive an
age of 2.5 10^6^yr for N81. We stress the importance of correcting the
continuum emission around Hβ for the nebular contribution. We derive
the gas electron density and temperature and compute the chemical
abundances of He, O, N, Ne, S, and Ar. The results are compared with
the mean values available for the SMC. The high resolution profile
of N81 at Hβ was decomposed into its various components. We find
the most probable three dimensional turbulent velocity in N81 to
be about 3 km s^-1^. We observationally confirm the proposition by
Koornneef and Israel (1985) that the H_2_ emission may be produced by
the action of a mild shock moving through the ambient cloud of this
nebula. Interestingly, unlike other representatives of this category
of H II regions in the Magellanic Clouds, N81 is not affected by the
local dust. The nebula N81 is associated with the SMC H I cloud of
radial velocity +167 km s^-1^, observed by McGee and Newton (1981). The
neighboring H II complexes N83 are associated with a density peak of
this H I cloud. N 88 A, another SMC H II blob, lying in the vicinity of
N 81, is associated with another H I cloud. We speculate that N 81 and
N 88 A may have been formed due to a collision between these two clouds.
---------------------------------------------------------
Title: Very low upper limits on the strength of interstellar lithium
lines toward SN 1987A.
Authors: Baade, D.; Magain, P.
1988A&A...194..237B Altcode:
Seven CCD and eleven Reticon spectra of high spectral resolution and
low noise have been carefully analysed in search for faint absorption
lines due to neutral interstellar lithium λ 6708 A along the line
of sight to SN 1987A in the Large Magellanic Cloud (LMC). At the
velocities of the strongest interstellar Ca II and Na I lines,
no evidence of any interstellar feature has been found. An upper
limit for the strongest components expected is 0.15 mA for both the
Galaxy and the LMC. From these we infer elemental column densities
N_Galaxy_ <= 2.6 10^11^ cm^-2^ and N_LMC_ <= 1.4 10^11^ cm^-2^
and gaseous elemental abundances (Li/H I)_Galaxy_ <= 7.7 10^-10^
and (Li/H I)_LMC_ <= 1.0 10^-10^ with an estimated uncertainty of
the abundance limits of a factor of 4 (0.6 dex).
---------------------------------------------------------
Title: Pre- and post-perihelion spectrographic and photometric
observations of Comet Wilson (1986 l)
Authors: Arpigny, C.; Dossin, F.; Manfroid, J.; Magain, P.; Haefner, R.
1988Msngr..51...27A Altcode:
The behavior of Comet Wilson before and after its passage through
perihelion, which occurred on April 21, 1987, was studied on the basis
of spectrographic and photometric observations. Results pertaining to
spectra in the UV, blue, and red regions, and to photometry through
narrow-band filters are presented. It is suggested that the fading of
Comet Wilson might reflect some general trend in the comet's evolution,
or that it could be the result of a geometrical effect associated with
the rotation of the comet's nucleus and the presence of discrete active
areas on its surface.
---------------------------------------------------------
Title: Search for Gravitational Lensing from a Survey of Highly
Luminous Quasars
Authors: Surdej, J.; Swings, J. -P.; Magain, P.; Borgeest, U.; Kayser,
R.; Refsdal, S.; Courvoisier, T. J. -L.; Kellermann, K. I.; Kuhr, H.
1988ASPC....2..183S Altcode: 1988osq..conf..183S
The authors have shown that their search for gravitational lensing
from a survey of optically selected highly luminous quasars (HLQ)
appears very promising. Observational features (multiple images,
image elongation, jet-like feature, fuzz, etc.) possibly associated
with the HLQ phenomenon have been detected for more than 20% of the
objects under study. While it is not yet known how many of the HLQs
are gravitational mirages, at least 5 (out of 111) of the investigated
quasars appear to be highly luminous because of amplification of their
brightness by gravitational lensing.
---------------------------------------------------------
Title: Could the gravitational lensing alter the observational data
in the extragalactic field?
Authors: Surdej, J.; Magain, P.; Swings, J. P.; Remy, M.; Borgeest,
U.; Kayser, R.; Refsdal, S.; Kühr, H.
1988lsso.conf...95S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Non-Lte Effects and Abundance Analyses of Halo Stars
Authors: Magain, P.
1988IAUS..132..485M Altcode:
The possible existence of departures from LTE affecting the abundance
analyses of halo dwarfs and subgiants is analysed from the observational
point of view, and illustrated by the case of the intermediate halo
subgiant HD 76932.
---------------------------------------------------------
Title: A new CCD camera for the Echelec spectrograph.
Authors: Gilliotte, A.; Magain, P.
1987Msngr..50...46G Altcode:
The Echelec spectrograph, installed at La Silla in 1973, was designed
to be used with an electronographic camera. However, by adding a
flatfield corrector, it can be operated with other detectors, such as
CCD's. As part of the upgrading programme of the 1.52-m telescope, and
in order to improve the spectroscopic capabilities of that instrument,
the Echelec spectrograph has been modified and is now working with
the same CCD detector as used on the Boiler and Chivens spectrograph.
---------------------------------------------------------
Title: Resolution of the OI + NH2 Blend in Comet p/ Halley
Authors: Arpigny, C.; Magain, P.; Manfroid, J.; Dossin, F.; Danks,
A. C.; Lambert, K. L.
1987A&A...187..485A Altcode:
Spectra of comet P/Halley have been taken at very high resolution
(0.015 nm) with a view to evaluating the contamination of
the forbidden oxygen doublet at 630 nm by NH<SUB>2</SUB>
features at low resolution. Comparison is made with a few other
bright comets. Appreciable variations are found not only in the
NH<SUB>2</SUB>/[O I] ratio but also in the relative intensities of the
various NH<SUB>2</SUB> emissions themselves. The authors comment upon
the accuracy obtained on the oxygen abundance derived from the [O I]
lines. Mapping of these emissions over the coma is required in order
to correctly remove any important NH<SUB>2</SUB> contribution at low
resolution. This should in addition provide information bearing upon
the origin of the oxygen atoms in the <SUP>1</SUP>D level.
---------------------------------------------------------
Title: A new case of gravitational lensing
Authors: Surdej, J.; Magain, P.; Swings, J. -P.; Borgeest, U.;
Courvoisier, T. J. -L.; Kayser, R.; Kellermann, K. I.; Kuhr, H.;
Refsdal, S.
1987Natur.329..695S Altcode: 1987Nat...329..695S
Even before the discovery of the first gravitational lens
system<SUP>1</SUP> in 1979 (see ref. 2 for a recent review of the
other published candidates), it was recognized that a statistical
evaluation of the occurrence of gravitational lensing within a
well-defined sample of quasars is important to understand better
the quasar luminosity function and possibly the QSO phenomenon
itself<SUP>3</SUP>, to test cosmological models<SUP>4,5</SUP> and to
probe the luminous and dark matter distribution on various scales in
the Universe<SUP>4-6</SUP>. A year ago, we began a systematic search
from the European Southern Observatory (ESO) at La Silla, Chile, for
gravitational lens systems in a selected sample of highly luminous
quasars; M<SUB>v</SUB><-29.0. These objects are promising candidates
for gravitationally lensed QSO images with arc-second and sub-arc-second
separations (J.S. et al., manuscript in preparation and refs 7 and
8). Since December 1986, we have identified four possible cases. Here
we give a brief description of our first identified gravitational
lens system UM673 = Q0142-100 =PHL3703<SUP>9-11</SUP>. It consists
of two images, A (m<SUB>R</SUB> = 16.9) and B (m<SUB>R</SUB> = 19.1),
separated by 2.2arcs at a redshift z<SUB>q</SUB> = 2.719. The lensing
galaxy (m<SUB>R</SUB>~ 19, Z<SUB>L</SUB>~0.49) has also been found. It
lies very near the line connecting the two QSO images, ~0.8 arc s
from the fainter one. Application of gravitational optometry to this
system leads to a value M<SUB>0</SUB>~2.4×10<SUP>11</SUP>Msolar for
the mass of the lensing galaxy and to δt~7 weeks for the most likely
travel-time difference between the two light paths to the QSO (assuming
H<SUB>0</SUB>= 75 km s<SUP>-1</SUP> Mpc<SUP>-1</SUP>,q<SUB>0</SUB> = 0).
---------------------------------------------------------
Title: Detection of interstellar CH and CH+ towards SN 1987A.
Authors: Magain, P.; Gillet, D.
1987A&A...184L...5M Altcode:
The authors report the detection of interstellar CH and CH<SUP>+</SUP>
towards supernova 1987A. For both of these molecules, one component is
detected at a heliocentric velocity of about 280 km/s, corresponding
to material inside the LMC. Some implications of the authors' results
with regards to the H<SUB>2</SUB>-to-dust ratio are briefly discussed.
---------------------------------------------------------
Title: Interstellar calcium towards supernova 1987A in the Large
Magellanic Cloud
Authors: Magain, Pierre
1987Natur.329..606M Altcode: 1987Nat...329..606M
We present high-resolution and high signal-to-noise spectra of
interstellar calcium towards SN1987A in the Large Magellanic Cloud
(LMC). They supplement previously published observations<SUP>1,2</SUP>
for Ca II and provide completely new results for the Ca I spectrum,
in which eleven components are detected, not only at velocities
corresponding to our Galaxy and the LMC, but also at intermediate
velocities. Our spectra, that allow us to estimate the ionization
balance in these interstellar clouds, provide some clues about their
physical state and location. In particular, the components between
150 and 200 km s<SUP>-1</SUP> show a much lower ionization degree than
other components. This may be due to recent compression of the gas by
a shock, possibly associated with a former supernova explosion. This
interpretation would require the corresponding clouds to be located
inside the LMC, indicating that at least some intermediate velocity
components are not of halo origin.
---------------------------------------------------------
Title: On the interpretation of the CH cometary spectrum.
Authors: Arpigny, C.; Zeippen, C. J.; Klutz, M.; Magain, P.;
Hutsemekers, D.
1987ESASP.278..607A Altcode: 1987dsc..proc..607A
A procedure to compute cometary spectra taking into account radiative
processes and collisional effects is described. The populations of the
rotational levels are determined by solving the statistical equilibrium
equations at a certain number of locations within the coma (which can be
modelled with n(R), T(R), v(R) laws) and the emerging intensity is then
evaluated by integrating the emissions along the line of sight. Such
a program was applied to the CH radical. The importance of collisions
in exciting the lower rotational levels of CH is confirmed.
---------------------------------------------------------
Title: On the forbidden red lines of oxygen in comets.
Authors: Arpigny, C.; Manfroid, J.; Magain, P.; Haefner, R.
1987ESASP.278..571A Altcode: 1987dsc..proc..571A
Eighteen spectra of 8 different comets observed at high and medium
resolution were analyzed in the 627 to 637 nm region to determine the
contributions of the (OI) red doublet and of the various NH2 lines
present in this wavelength interval. Results confirm that there exist
appreciable variations not only in the (OI)/NH2 ratio, but also in the
relative intensities of the NH2 features among themselves, therefore,
it is not justified to derive the (OI) line flux from the 630.0 blend,
as was done in previous low-resolution work, by assuming a fixed
relative strength of the NH2 emission contained in this blend. Mapping
of these emissions over the coma is recommended.
---------------------------------------------------------
Title: High Resolution Spectroscopy and Analysis of the
C<SUB>2</SUB>(0,0) Band in Comet P/Halley
Authors: Danks, A. C.; Lambert, D. L.; Sheffer, Y.; Arpigny, C.;
Dossin, F.; Magain, P.
1987BAAS...19.1124D Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The missing opacity and the temperature calibration of
solar-type stars.
Authors: Magain, P.
1987A&A...181..323M Altcode:
The novel temperature calibration of some color indices presented for
G and F dwarfs is based on the IR flux method and extends the work of
Saxner and Hammarback (1985) to the Population II stars. Attention
is given to the discrepancy between theoretical and empirical
temperature calibrations. It is suggested that the most straightforward
interpretation of the disagreement between empirical colors and some
model predictions is that of the 'missing opacity' due to a veil of
faint metal lines, present in the blue and UV regions of the spectra
of solar-type and cooler stars, but excluded from the model.
---------------------------------------------------------
Title: HD 151932 variability revisited.
Authors: Vreux, J. M.; Magain, P.; Manfroid, J.; Scuflaire, R.
1987A&A...180L..17V Altcode:
The observation of variations in the blue absorption component of the
He I lines as well as in the Si IV 4089 emission line of HD 151932 is
reported. Possible explanations for these variations are addressed,
and it is concluded that none is satisfactory. The possibility of a
periodicity in the variations is briefly considered.
---------------------------------------------------------
Title: Abundances of light elements in halo dwarfs : a re-analysis.
Authors: Magain, P.
1987A&A...179..176M Altcode:
The abundances of a few light elements in the atmospheres of halo
dwarfs are redetermined on the basis of literature data reanalysed in
an homogeneous way. It is shown that the scatter of the resulting Mg
and Al abundances is strongly reduced and that no discrepancy remains
between the abundances deduced from blue and red lines. Mg, Si and
Ca show constant overabundances while the Al overdeficiency seems in
agreement with the predictions of explosive carbon burning.
---------------------------------------------------------
Title: Photometric Observations of WR78 = HD 151932
Authors: Magain, P.; Vreux, J. M.; Manfroid, J.
1987IBVS.3022....1M Altcode:
No abstract at ADS
---------------------------------------------------------
Title: BD +03 deg 740 - A new extreme metal-poor dwarf
Authors: Magain, P.
1987Msngr..47...18M Altcode:
The results of a preliminary analysis of BD +03 deg 740 are
presented. The analysis was based on the blue spectrum which was
obtained with an exposure time of 40 min, giving a good S/N ratio
for this 9.8-mag star. Graphs are presented which reveal the extreme
weakness of the metal lines in the spectrum. The analysis of BD +03 deg
740, which is the most metal-poor dwarf in which s element abundances
have been determined, confirms the presence of secondary elements in
the atmospheres of the extreme halo dwarfs.
---------------------------------------------------------
Title: Supernova 1987A in the Large Magellanic Cloud
Authors: Cristiani, S.; Gouiffes, C.; Hanuschik, R.; Magain, P.;
Dawe, J.; McNaught, R. H.; Beresford, T.
1987IAUC.4350....1C Altcode: 1987IAUC.4350....0C
S. Cristiani and C. Gouiffes, European Southern Observatory;
R. Hanuschik, Bochum University; and P. Magain, ESO, report: "Spectra
taken at intermediate resolution (0.2-0.3 nm) between Mar. 14 and
22, with the spectrum scanner attached to the Bochum University
0.61-m telescope and with the ESO 1.5-m telescope at La Silla,
showed changes in the P-Cyg profile of H-alpha. On Mar. 15, a weak
bump at 647 nm appeared on the previously-very-smooth P-Cyg profile
(near the bottom of the absorption) which developed in the following
days, assuming a peaked structure and reaching the continuum level
about Mar. 20. A comparison with previous spectra suggests that this
is an additional emission feature. Spectra taken with the CAT 1.4-m
telescope (resolution 80000) do not show smaller- scale structures. The
precise wavelength of the relative maximum in the spectrum is 647.0 nm,
followed by a minimum at 648.8 nm. The FWHM of the two features is 1.45
and 2.10 nm, respectively. If identified with H-alpha, the emission
corresponds to a velocity of -4500 km/s. No corresponding structures
have been observed in the P-Cyg profiles of H-beta and Ca 860-nm. Those
observations suggest a distortion in the spherical symmetric outflow of
the explosion, which can be confirmed by polarization observations of
the H-alpha profile." Provisional photoelectric photometry by J. Dawe
and R. H. McNaught with the Australian National University 0.61-m
reflector at Siding Spring Observatory: Mar. 20.456 UT, V = 4.12, B-V
= +1.58, U-B = +2.04. Further visual magnitude estimates: Mar. 19.39,
4.1 (McNaught); 19.52, 4.0 (T. Beresford, Adelaide, South Australia);
20.45, 4.0 (McNaught); 20.48, 3.9 (Beresford).
---------------------------------------------------------
Title: Supernova 1987A in the Large Magellanic Cloud
Authors: Cristiani, S.; Gouiffes, C.; Hanuschik, R.; Magain, P.;
Dawe, J.; McNaught, R. H.; Beresford, A.
1987IAUC.4350.....C Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Resolution of the [O I]+NH<SUB>2</SUB> blend in comets.
Authors: Arpigny, C.; Magain, P.; Manfroid, J.; Dossin, F.; Haefner, R.
1987LIACo..27..315A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Very Low Upper Limits on the Strength of Interstellar Lithium
Lines Toward Supernova 1987A
Authors: Baade, D.; Magain, P.
1987ESOC...26..537B Altcode: 1987sn...work..537B
No abstract at ADS
---------------------------------------------------------
Title: CES+CCD Observations of Interstellar Lines Towards Supernova
1987A
Authors: Magain, P.
1987ESOC...26..533M Altcode: 1987sn...work..533M
No abstract at ADS
---------------------------------------------------------
Title: High resolution spectroscopy with the E.S.O. Coudé Echelle
Spectrometer.
Authors: Magain, Pierre
1987LIACo..27...15M Altcode: 1987oahp.proc...15M
Various applications of high resolution spectroscopy with the ESO Coude
Echelle Spectrometer (CES) are discussed. The aim of this paper is not
to present a complete survey of the CES capabilities, but to illustrate
some possible applications, with emphasis on rather unusual aspects. In
all the observations presented here, the CES has been used with the new
short camera and a CCD detector (high resolution RCA SID 503, 640 x 1024
pixels, 15x15 microns each). Compared to the long camera and Reticon
detector, this new combination represents an increase of efficiency
of 2 to 3 magnitudes with only a moderate loss of resolving power.
---------------------------------------------------------
Title: Resolution of the (OI)+NH<SUB>2</SUB> Blend in Comet P/halley
Authors: Arpigny, C.; Magain, P.; Manfroid, J.; Dossin, F.; Danks,
A. C.; Lambert, D. L.
1986ESASP.250c..81A Altcode:
Spectra of P/Halley were taken at very high resolution (0.15A)
to evaluate contamination of the forbidden oxygen doublet by NH2
features at low resolution. Comparison is made with other bright
comets. Appreciable variations are found in the NH2/(OI) ratio and
in the relative intensities of the NH2 emissions themselves. The
accuracy obtained on the oxygen abundance derived from the (OI) lines
is discussed. Mapping of these emissions over the coma is required to
correctly remove any important NH2 contribution at low resolution. This
should also provide information on the origin of the oxygen atoms in
the 1D level.
---------------------------------------------------------
Title: Spectroscopy, Photometry and Direct Filter Imagery of Comet
P/Halley
Authors: Arpigny, C.; Dossin, F.; Manfroid, J.; Magain, P.; Danks,
A. C.; Lambert, D. L.; Sterken, C.
1986Msngr..45....8A Altcode: 1986Msngr..45....8S
Observational techniques and instrumentation applied in ground-based
studies of the cometary coma during the post-perihelion phase of
the recent passage of Comet Halley are summarized. Applications of
a 1.5 m telescope equipped with a coude spectrograph for long slit
investigations of spectral intensity distributions, a 1.4 m CAT,
coude echelle spectrometer and reticon to evaluate the C-12/C-13
isotopic abundance ratio, and a 50 cm photometric telescope for
narrow bandwidth spectroscopy are described. Finally, the 1.5 m Danish
telescope, equipped with a CCD camera, collected high spatial resolution
photographs of the various coma components when the comet was 0.42 AU
from the sun.
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Title: Contribution functions and the depths of formation of
spectral lines
Authors: Magain, P.
1986A&A...163..135M Altcode:
A rigorous expression is derived for the contribution function to the
spectral line depression in a stellar atmosphere; this, in effect, gives
the contribution of the different atmospheric layers to the formation of
the line depression. This contribution function is the solution of the
transfer equation for the line depression. It is the only appropriate
distribution function for the computation of the depths of formation of
spectral lines. It indicates, in contrast to some earlier contribution
functions, that a faint spectral line is not necessarily formed in
the same layers as the continuum. The response function of the line
depression to a given perturbation is briefly discussed.
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Title: Spectroscopic analysis of extreme metal-poor
”dwarfs”. II. Improvedmodel atmospheres and detailed abundances.
Authors: Magain, P.
1985A&A...146...95M Altcode:
High resolution spectrophotometric data were obtained for the stellar
objects HD 19445 and HD 140283. The spectra gathered were well-matched
by model stellar atmospheres for the continuous flux and Fe I excitation
equilibrium. HD 19445 was identified as a dwarf star and HD 140283
as a subgiant. Abundance analyses indicated an Fe abundance lower
than previously estimated, oxygen overabundant relative to C and Fe,
Mg, Si and Ca overabundant relative to Fe, and deficiencies of Al and
Mn. Sr was overabundant relative to Ba. The abundance discrepancies are
in disagreement with the standard nucleosynthesis model. Further such
spectroscopic data are needed to develop accurate galactic chemical
evolution models.
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Title: A comment on systematic errors in determinations of
microturbulent velocities
Authors: Magain, P.
1984A&A...134..189M Altcode:
It is shown that the usual method of microturbulent velocity
determination from the "abundance versus equivalent width" plot leads
to a systematic overestimate of the microturbulent velocity when
the observd equivalent widths are affected by random errors. This
overestimate is due to the correlation between errors in observed
equivalent widths and in line abundances. This error rises rapidly with
decreasing quality of the observational material and may be avoided
by using theoretical equivalent widths instead of observed ones as
abscissa of the "abundance versus equivalent width" plot.
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Title: Spectroscopic analysis of extreme metal-poor
'dwarfs'. I. Observational material, Fe lines, and model atmospheres.
Authors: Magain, P.
1984A&A...132..208M Altcode:
Fe lines are analysed in the spectra of the two extreme metal-poor
stars MD 19445 and MD 140283 on the basis of new observational
material. It is shown that the use of accurate equivalent widths
and very accurate oscillator strengths improves significantly the
quality of the analysis. In particular, these stars are found to be
more metal-deficient than precedingly thought. This result may imply a
significant revision of the adopted abundance scale. It is shown that
differential analyses of such stars relative to the Sun are subject to
important systematic errors due to the very large difference between
the stellar and solar equivalent widths. Finally, the temperature
criteria are analysed and it is argued that the criteria linked to deep
atmospheric layers, such as the B - V colour or the hydrogen line wings,
should not be used to select a model representing satisfactorily the
line-forming layers.
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Title: Etude détaillée d'étoiles froides pauvres en métaux Title:
Etude détaillée d'étoiles froides pauvres en métaux Title:
Detailed study of cold metal-poor stars;
Authors: Magain, Pierre
1984PhDT.......162M Altcode:
No abstract at ADS
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Title: A Test of the Planck-Larkin Partition Function
Authors: Magain, P.
1984LIACo..25..234M Altcode: 1984trss.conf..234M; 1984tpss.conf..234M
No abstract at ADS
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Title: The A1/Mg abundance ratio in halo stars.
Authors: Arpigny, C.; Magain, P.
1983A&A...127L...7A Altcode:
The Al to Mg abundance ratio is redetermined in two extreme metal-poor
stars, HD 19445 and HD 140283, on the basis of accurate spectral
material. It is found that: (1) one of the two lines used for the
Al abundance determination is blended by CH lines; (2) no anomalous
difference appears between the hotter and the cooler star, both showing
an Al overdeficiency; (3) the observations are in fair agreement with
predictions from the theory of explosive carbon burning.
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Title: The missing UV opacity and the colours of solar-type stars.
Authors: Magain, P.
1983A&A...122..225M Altcode:
A simple method is proposed to take into account the "missing UV
opacity" in solar-type stars. It is shown that the mere inclusion of
that UV opacity through a very simple formula is sufficient to bring
the theoretical colours in agreement with observed ones for stars of
different metal abundances and belonging to the spectral range from
mid-F to late-G. Synthetic colours computed in the Geneva and UBV
systems reproduce the various observed relations satisfactorily. The
relations based on these colours allow reliable estimates of effective
temperatures, surface gravities and metal abundances of stars. In
addition, solar colours are obtained and three more solar twin
candidates are proposed.
