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Author name code: smaldone
ADS astronomy entries on 2022-09-14
author:"Smaldone, Luigi A."
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Title: Quantum groups and polymer quantum mechanics
Authors: Acquaviva, G.; Iorio, A.; Smaldone, L.
2021MPLA...3650229A Altcode: 2021arXiv210514792A
In Polymer Quantum Mechanics, a quantization scheme that naturally
emerges from Loop Quantum Gravity, position and momentum operators
cannot be both well defined on the Hilbert space (ℋPoly). It
is henceforth deemed impossible to define standard creation and
annihilation operators. In this paper, we show that a q-oscillator
structure, and hence q-deformed creation/annihilation operators, can be
naturally defined on ℋPoly, which is then mapped into the sum of many
copies of the q-oscillator Hilbert space. This shows that the q-calculus
is a natural calculus for Polymer Quantum Mechanics. Moreover, we show
that the inequivalence of different superselected sectors of ℋPoly
is of topological nature.
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Title: Bekenstein bound from the Pauli principle
Authors: Acquaviva, G.; Iorio, A.; Smaldone, L.
2020PhRvD.102j6002A Altcode: 2020arXiv200513973A
Assuming that the degrees of freedom of a black hole are finite
in number and of fermionic nature, we naturally obtain, within a
second-quantized toy model of the evaporation, that the Bekenstein
bound is a consequence of the Pauli exclusion principle for these
fundamental degrees of freedom. We show that entanglement, Bekenstein,
and thermodynamic entropies of the black hole all stem from the
same approach, based on the entropy operator whose structure is the
one typical of Takahashi and Umezawa's thermofield dynamics. We then
evaluate the von Neumann black hole-environment entropy and noticeably
obtain a Page-like evolution. We finally show that this is a consequence
of a duality between our model and a quantum dissipativelike fermionic
system.
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Title: Information entropy in solar atmospheric fields. I. Intensity
photospheric structures
Authors: Consolini, G.; Berrilli, F.; Florio, A.; Pietropaolo, E.;
Smaldone, L. A.
2003A&A...402.1115C Altcode:
The existence of a quasi-regular pattern in solar photospheric
convective fields is an open question. In the present work, this problem
is quantitatively approached by means of the normalised information
entropy measure H'(r) as introduced by Van Siclen (\cite{VanSic97}),
which reports on the information content at different scales. Images
were acquired at the THEMIS telescope of the European Northern
Observatory by the IPM observing mode, and at the Richard B. Dunn
Solar Telescope of the National Solar Observatory. The evaluation of
H'(r) in the case of photospheric intensity binarized images shows the
presence of maxima which are evidence of different prominent scales
in the photospheric pattern. The relative positions of these maxima
defines an ordering scale ~ 1.6 Mm in both instantaneous and average
images. This is read as the evidence of a spatio-temporal organization
in the evolution of convective pattern. The emergence of an ordering
scale is discussed in the framework of pattern formation in random
systems and in connection with the findings of previous works. By
averaging images with time, an increase of the information content
characterized by a coherence time of ~ 1 h is observed in the range
of scales from 5.0 Mm to 10.0 Mm.
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Title: Solar and Heliospheric Observatory/Coronal Diagnostic
Spectrograph and Ground-based Observations of a Two-Ribbon Flare:
Spatially Resolved Signatures of Chromospheric Evaporation
Authors: Teriaca, L.; Falchi, A.; Cauzzi, G.; Falciani, R.; Smaldone,
L. A.; Andretta, V.
2003ApJ...588..596T Altcode:
During a coordinated observing campaign (Solar and Heliospheric
Observatory, SOHO JOP 139), we obtained simultaneous spectroheliograms
of a solar active region in several spectral lines, sampling levels
from the chromosphere to the corona. Ground-based spectroheliograms
were acquired at the Dunn Solar Tower of the National Solar
Observatory/Sacramento Peak in four chromospheric lines, while the
coronal diagnostic spectrograph on board SOHO was used to obtain
rasters of the active region in transition region (TR) and coronal
lines. Such a complete data set allowed us to compare the development
of intensity and velocity fields during a small two-ribbon flare
in the whole atmosphere. In particular, we obtained for the first
time quasi-simultaneous and spatially resolved observations of
velocity fields during the impulsive phase of a flare, in both the
chromosphere and upper atmosphere. In this phase, strong downflows
(up to 40 km s<SUP>-1</SUP>) following the shape of the developing
ribbons are measured at chromospheric levels, while strong upward
motions are instead measured in TR (up to -100 km s<SUP>-1</SUP>)
and coronal lines (-160 km s<SUP>-1</SUP>). The spatial pattern of
these velocities have a common area about 10" wide. This is the first
time that opposite-directed flows at different atmospheric levels
are observed in the same spatial location during a flare. These
signatures are highly suggestive of the chromospheric evaporation
scenario predicted in theoretical models of flares.
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Title: Mass Motions in a Young Active Region
Authors: Cauzzi, G.; Falchi, A.; Falciani, R.; Smaldone, L. A.
2003MmSAI..74..659C Altcode:
We present an observational program devoted to the study of dynamic
phenomena at small spatial and temporal scales throughout the solar
atmosphere, with special attention to chromospheric events that have
an impact on the coronal structure. On the one hand, we show the
existence of flare signatures in the chromosphere at the smallest
scales, supporting the idea that (micro)flares represent a viable
mechanism for supply of heat and mass to the corona. On the other,
such events are quite scarce in our dataset, while much more common
are surge-like events, occurring repeatedly in the same locations
and visible both in the chromosphere and the corona, and that do not
display obvious flare signatures.
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Title: Spatially resolved signatures of chromospheric evaporation
during a small two-ribbon flare
Authors: Teriaca, L.; Falchi, A.; Cauzzi, G.; Falciani, R.; Smaldone,
L. A.; Andretta, V.
2003MmSAI..74..635T Altcode:
Ground based spectroheliograms of a solar active region were acquired
in four chromospheric lines simultaneously with rasters in transition
region (TR) and coronal lines obtained with the Coronal Diagnostic
Spectrograph (CDS) aboard SOHO. Such a complete dataset allows us to
study the development of intensity and velocity fields during a small
two-ribbon flare in the whole atmosphere. In particular, we obtain for
the first time quasi-simultaneous and spatially resolved observations
of velocity fields during the impulsive phase of a flare, both in
chromosphere and upper atmosphere. In this phase, strong downflows
(up to 40 km s<SUP>-1</SUP>) following the shape of the developing
ribbons are measured at chromospheric levels, while strong upward
motions are measured in TR (up to -100 km s<SUP>-1</SUP>) and coronal
lines (-160 km s<SUP>-1</SUP>). The spatial pattern of these velocities
have a common area about 10 arcsec wide. This is the first time that
opposite directed flows at different atmospheric levels are observed
in the same spatial location during a flare. These signatures are
highly suggestive of the chromospheric evaporation scenario predicted
in theoretical models of flares.
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Title: CONCORDIASTRO/Italy: A Solar High-Resolution Observation
Program at Dome-C
Authors: Severino, G.; Andretta, V.; Berrilli, F.; Cascone, E.;
Centrone, M.; Criscuoli, S.; Del Moro, D.; Ermolli, I.; Giorgi, F.;
Jefferies, S. M.; Magri, M.; Moretti, P. F.; Oliviero, M.; Parisi,
L.; V; Porzio; Smaldone, L. A.; Straus, Th.
2003MSAIS...2..181S Altcode:
CONCORDIASTRO is the Nice-Napoli joint project for site
testing of the Dome C for solar and stellar astronomy in the
visible. CONCORDIASTRO/Italy is the solar physics part of this project,
whose the Napoli team has the principal responsibility. Beyond the
well-known interest for the helioseismology, CONCORDIASTRO/Italy pointed
out that, because of its special atmospheric conditions, Dome C promises
to be one of the best sites on Earth to perform high-resolution solar
physics. Here we review the basis for this statement and the solar
observations program planned by CONCORDIASTRO/Italy.
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Title: Chromospheric and Transition region He lines during a flare
Authors: Falchi, A.; Mauas, P. J. D.; Andretta, V.; Teriaca, L.;
Cauzzi, G.; Falciani, R.; Smaldone, L. A.
2003MmSAI..74..639F Altcode:
An observing campaign (SOHO JOP 139), coordinated between ground
based and SOHO instruments, has been planned to obtain simultaneous
spectroheliograms of the same area in several spectral lines. The
chromospheric lines Ca II K, Hα and Na I D as well as He I 10830,
5876, 584 and 304 Ålines have been observed. These observations allow
us to build semi-empirical models of the atmosphere before and during
a small flare. With these models, constructed to match the observed
line profiles, we can test the He abundance value.
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Title: Chromospheric evaporation in a two-ribbon flare
Authors: Cauzzi, G.; Falchi, A.; Teriaca, L.; Falciani, R.; Smaldone,
L. A.; Andretta, V.
2002ESASP.506..561C Altcode: 2002ESPM...10..561C; 2002svco.conf..561C
We present simultaneous, spatially and temporally resolved
chromospheric, transition region and coronal observations of a small
eruptive flare studied throughout its whole development. We show
that strong and co-spatial plasma motions, oppositely directed in the
chromosphere (downflows) and in upper atmospheric layers (upflows),
develop at the onset of the flare. For the first time, we prove that
such oppositely directed flows originate from the same flaring kernels
in different atmospheric layers. Using realistic values for the plasma
parameters in the flaring loop, we also estimate a balance between
the upward and downward momenta. Our observations confirm in a very
convincing way the scenario of chromospheric evaporation predicted in
theoretical models of flares.
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Title: Combined space and ground based observations of a C-1 flare
Authors: Teriaca, L.; Falchi, A.; Cauzzi, G.; Falciani, R.; Smaldone,
L. A.; Andretta, V.
2002ESASP.508..457T Altcode: 2002soho...11..457T
We present temporally and spatially resolved space and ground based
observations of a C1 flare. Ground based spectroheliograms were acquired
at the Dunn Solar Tower of NSO/Sacramento Peak in several chromospheric
lines. Simultaneously, the Coronal Diagnostic Spectrograph (CDS)
aboard SoHO was used to obtrain rasters of the same active region
in transiton region (TR) and coronal lines. This unique dataset
provides us, for the first time, with spatially resolved observations
of velocity fields during the impulsive phase of the flare, from the
chromosphere up to the TR and the corona. At the time of the emission
peak, a large area of the flaring kernel observed in TR lines is
characterized by upward velocities. A ~6"×6" kernel displays upflows
velocity above 80 km s<SUP>-1</SUP>. In this same area we found, in
data obtained about 3 minutes later, chromospheric downflows of 10 -
20 km s<SUP>-1</SUP>. This is the first time that opposite directed
flows at different atmospheric levels are observed in the same spatial
location during a flare.
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Title: Foreword (SOLSPA 2001)
Authors: Schmieder, Brigitte; Smaldone, Luigi
2002ESASP.477D..15S Altcode: 2002scsw.confD..15S
No abstract at ADS
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Title: Understand spectroheliograms - insight from spectral line
analysis
Authors: Smaldone, L. A.; Scognamiglio, O.; Balasubramaniam, K. S.
2001MmSAI..72..553S Altcode:
In an effort to seek newer diagnostic tools for monitoring the solar
activity, we have reconstructed spectroheliograms in various spectral
lines in the range 3900-3940 Angstroms (around the Ca II K line), from
high spatial and spectral resolution measurements. In active regions,
we find that the spectroheliogram features in a number of spectral lines
are similar to the Ca II K1v spectroheliogram features. In plages, on
the contrary, only spectroheliograms in a few spectral lines correlate
with the Ca II K1v. In plages, we get the best correlation with the
Si I 3905. From these measurements we develop contrast functions to
isolate various active phenomena as seen in Ca II, and compare its
formation contribution of relative velocities, magnetic fields and
intensity as seen in Fe I and Si I spectral lines. These indicators
provide much insight into the formation of Ca II K line.
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Title: A chromospheric model for FU Ori
Authors: D'Angelo, G.; Errico, L.; Gomez, M. T.; Smaldone, L. A.;
Teodorani, M.; Vittone, A. A.
2000A&A...356..888D Altcode:
We present medium and high-dispersion optical spectra of the
FUOr variable FU Ori, demonstrating that some lines are subject to
variability both on a yearly and on a daily time scale. Some raw models
of accretion disk atmospheres are presented in order to explain both
qualitatively and quantitatively the dynamics of the observed line
variability. Computing synthetic profiles for the Hα line by using
the non-LTE MULTI code, we find that the emission component of this
feature is very sensitive to the temperature gradient and the maximum
temperature reached in a chromospheric-like layer. Further, the blue
absorption component of the Hα depends only on the velocity field
of the wind and the transition between the absorption and emission
components is produced where the chromosphere ends and the wind
begins. Similar chromospheric analysis is applied to the profile of
the Na I D lines in pure absorption.
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Title: FU Orionis: an accretion disk with an active chromosphere ?
Authors: D'Angelo, G.; Gomez, M. T.; Errico, L.; Smaldone, L. A.;
Vittone, A. A.
2000MmSAI..71.1037D Altcode:
No abstract at ADS
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Title: Wavelet Analysis of Spatial Coherent Structures in the
Photosphere
Authors: Pietropaolo, E.; Berrilli, F.; Consolini, G.; Smaldone,
L. A.; Straus, T.; Cauzzi, G.; Bruno, R.; Bavassano, B.
1999ESASP.448..343P Altcode: 1999ESPM....9..343P; 1999mfsp.conf..343P
No abstract at ADS
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Title: Simultaneous 2-D Spatial Spectra Using a Microlens Array
Authors: Balasubramaniam, K. S.; Suematsu, Y.; Smaldone, L. A.;
Yoshimura, K.; Hegwer, S.; Otani, H.
1999AAS...194.9306B Altcode: 1999BAAS...31R.989B
Simultaneous spatial spectra of extended solar structures, at a high
spatial resolution and temporal cadence is important to track and
understand the physics of dynamical evolutionary phenomena. Replacing
the slit of a conventional spectrograph with a micro-lens array will
then help to capture simultaneous spatial spectra using a large format
CCD camera. Such a technique will be useful to study small structures
(a few arcseconds across) such as Ellerman bombs, kernels of flares,
filamentary evolution and spicules. At the NSO/Richard B. Dunn Solar
Telescope, we have used a micro-lens array (0.6 mm pitch, 50 x 50
lens-lets) to observe structures with a spatial sampling of 0.24
arcseconds in Hα \ spectral line. The spectral sampling is 0.93
Angstroms/pixel over a 10- Angstroms bandwidth. The field-of-view
is however limited to about 12 arcseconds. We have also explored the
microlens array the observations to magnetic spectral lines such as
FeI 6301.5 and FeI 6302.5 Angstroms for variation of line-of-sight
of subarcsecond magnetic fields. We present initial results from an
engineering observational experiment at the Dunn Solar Telescope.
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Title: Effects of the Spectral and Spatial Resolution on the Detection
of K2v Grains
Authors: Smaldone, L.; Salvatore, A.
1999ASPC..183..412S Altcode: 1999hrsp.conf..412S
No abstract at ADS
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Title: Velocities in Solar Pores
Authors: Keil, S. L.; Balasubramaniam, K. S.; Smaldone, L. A.;
Reger, B.
1999ApJ...510..422K Altcode:
We use high spatial and spectral resolution filtergrams to examine the
three-dimensional morphology and velocity fields associated with solar
pores in a region of newly emerged magnetic flux. The observed amplitude
of the horizontal surface velocities decreases near the pores. Most of
the pores exhibit a downflow in the surrounding region. Time-averaged
line-of-sight velocities in and near the pores increased with the
strength of the associated magnetic field. The LOS velocities are
such that the maximum downflow is not centered about the continuum
intensity and sometimes traces an annulus ringlike structure around
the pore. From a time sequence of continuum images, it appears that
some pores shed flux at the photospheric level. “Cork movies” of the
surface velocities show that the “corks” are advected toward weak
downflows near the pore locations and that the loci of the advected
corks trace boundaries that resemble mesogranular and supergranular
flows. We analyze the vertical velocity structure in pores and show that
the downflow decreases exponentially with height, with a scale height
that is a factor of 2 smaller than the photospheric scale height for
granules. The line-of-sight flow associated with the pores appears
to expand with height. Our observations are compared with previous
measurements of flows in and around pores that were based on both
spectrograms and filtergrams. Finally, we provide a phenomenological
description for pores.
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Title: Chromospheric K<SUB>2v</SUB> grains properties
Authors: Salvatore, A.; Smaldone, L. A.
1998MmSAI..69..639S Altcode:
No abstract at ADS
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Title: The Wind of FU Orionis: Modelling the Atmosphere
Authors: D'Angelo, G.; Errico, L.; Gomez, M. T.; Smaldone, L. A.;
Teodorani, M.; Vittone, A. A.
1998cvsw.conf..323D Altcode:
No abstract at ADS
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Title: Properties of solar granulation cells in quiet regions as
derived from a time series of white light images
Authors: Cauzzi, G.; Consolini, G.; Berrilli, F.; Smaldone, L. A.;
Straus, T.; Bavassano, B.; Bruno, R.; Caccin, B.; Carbone, V.; Egidi,
A.; Ermolli, I.; Florio, A.; Pietropaolo, E.
1998MmSAI..69..647C Altcode:
No abstract at ADS
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Title: The Magneto-Optical Filter in Napoli: Perspectives and Test
Observations
Authors: Moretti, P. F.; Severino, G.; Cauzzi, G.; Reardon, K.;
Straus, T.; Cacciani, A.; Marmolino, C.; Oliviero, M.; Smaldone, L. A.
1997ASSL..225..293M Altcode: 1997scor.proc..293M
An observing station based on the Magneto-Optical-Filter (MOF)
technology is being installed at Osservatorio Astronomico di
Capodimonte, in Napoli. In this paper, the main characteristics and
goals of this new instrument are discussed, and several velocity and
magnetic observations from a test campaign are shown.
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Title: Active region effects on solar irradiance at NA I D lines
Authors: Marmolino, C.; Oliviero, M.; Severino, G.; Smaldone, L. A.
1997A&AS..125..381M Altcode:
The possibility to detect solar oscillations in the low frequency domain
depends crucially on the power contrast among the oscillation signal and
other time dependent signals in the same frequency range. The signal to
noise ratio is increased by our ability to understand and remove solar
sources of noise. In measurements of the mean Doppler velocity shift of
the integrated solar disk, the solar noise has a line component spectrum
with a major peak at 13.1 days, and a second less prominent peak at 27.2
days. Active region modulation is believed almost completely responsible
for this signal. We develop simulations of the flux and velocity
fluctuations produced by different solar active region distributions,
based on an analytical description of their action. From a grid of
models of active regions and from their spatial distribution over the
disk, we calculate the synthetic flux profile in the Na I D<SUB>1</SUB>
line and determine the velocity measure of a resonance spectrometer. Our
velocity results are compared with the offset velocities from the IRIS
network. There is a rather good agreement between the observed and
computed velocities, and the plage contribution to the noise appears to
be dominant. The simulation allows to test calibration procedures and
to study the effect on the spurious velocities of different parameters,
such as the intensity thresholds used to determine the areas of spots
and plages, and the contrast of the active regions. In particular, we
find that the inclusion of intrinsic line shifts in plages can change
strongly both the amplitude and the shape of the simulated signal,
and then may be an important source of uncertainty for the simulation.
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Title: Multispectral Observations of AN Eruptive Flare
Authors: Qiu, J.; Falchi, A.; Falciani, R.; Cauzzi, G.; Smaldone, L. A.
1997SoPh..172..171Q Altcode: 1997ESPM....8..171Q
We analyze the pre-flare and impulsive phase of an eruptive (two-ribbon)
flare at several wavelengths. The total energy (mechanical plus
radiative) released by the flare is 8 x 10<SUP>30</SUP> erg, about a
factor 6 higher than the free magnetic energy (1.3 10<SUP>30</SUP> erg)
estimated from the non-potentiality of the magnetic field configuration
in the flare area. During the impulsive phase, we find a very good time
coincidence between the hard X-ray light curve and the light curves
for 2 small areas (≃ 4″ in size) in the red wing of the Hα line
and in the He-D<SUB>3</SUB> line center. This temporal coincidence is
compatible with the interpretation that hard X-ray emission is produced
by bremsstrahlung of accelerated electron beams striking these dense
areas. For the other regions of the Hα ribbons we find more gradual
light curves, suggesting a different energy transport mechanism such
as conduction.
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Title: Dynamics of Minor Solar Activity \newline Coordinated
Observations SOHO-GBO JOP #37
Authors: Cauzzi, G.; Vial, J. C.; Falciani, R.; Falchi, A.; Smaldone,
L. A.
1997ASPC..118..309C Altcode: 1997fasp.conf..309C
We present a program for coordinated observations between ground based
observatories, mainly NSO/Sacramento Peak, and several instruments
onboard SOHO (primarily SUMER). The scientific goal is the study of
small activity phenomena, at high spatial and temporal resolution.
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Title: ARTHEMIS: The archive project for the Italian Panoramic
Monochromator
Authors: Reardon, K.; Severino, G.; Cauzzi, G.; Gomez, M. T.; Straus,
T.; Russo, G.; Smaldone, L. A.; Marmolino, C.
1997MmSAI..68..499R Altcode:
No abstract at ADS
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Title: Simultaneous Doppler and magnetic solar maps from a MOF
installed at the Osservatorio di Capodimonte
Authors: Cacciani, A.; Marmolino, C.; Moretti, P. F.; Oliviero, M.;
Severino, G.; Smaldone, L. A.
1997MmSAI..68..467C Altcode:
No abstract at ADS
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Title: Velocities in Solar Pores
Authors: Balasubramaniam, K. S.; Keil, S. L.; Smaldone, L. A.
1996AAS...188.0203B Altcode: 1996BAAS...28..820B
We investigate the three dimensional structure of solar pores and
their surroundings using high spatial and spectral resolution data. We
present evidence that surface velocities decrease around pores with
a corresponding increase in the line-of-sight (LOS) velocities. LOS
velocities in pores increase with the strength of the magnetic
field. Surface velocities show convergence toward a weak downflow which
appear to trace boundaries resembling meso-granular and super granular
flows. The observed magnetic fields in the pores appear near these
boundaries. We analyze the vertical velocity structure in pores and show
that they generally have downflows decreasing exponentially with height,
with a scale height of about 90 km. Evidence is also presented for the
expanding nature of flux tubes. Finally we describe a phenomenological
model for pores. This work was supported by AFOSR Task 2311G3. LAS was
partially supported by the Progetto Nazionale Astrofisica e Fisica
Cosmica of MURST and Scambi Internazionali of the Universita degli
Studi di Napoli Frederico II. National Solar Observatory, NOAO, is
operated for the National Science Foundation by AURA, Inc.
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Title: Coordinated observations of solar activity phenomena. II. The
velocity field pattern in an elementary flare.
Authors: Cauzzi, G.; Falchi, A.; Falciani, R.; Smaldone, L. A.
1996A&A...306..625C Altcode:
We present the line-of-sight velocity pattern determined from spectra
obtained before and during a small flare, whose emission properties have
been studied in Cauzzi et al. (1995, Paper I). The flare hard X-ray
(HXR) emission, in the range 25-100keV, consists of five separate
and short spikes (lasting 1-7s), which suggests that this flare
is a sequence of separate elementary bursts. 40 seconds before the
occurrence of any HXR emission the flare kernel is already bright in
H<SUB>alpha</SUB>_+1.5A and shows a typical chromospheric flare spectrum
with Balmer lines in emission up to H_13_. Also, few seconds before
the impulsive phase of the flare (as marked by the occurrence of the
first HXR spike) an upward motion is determined from lines originating
in high chromospheric layers (CaII K and H<SUB>delta</SUB>_) and from
metallic lines (Si I 3905, Fe I multiplets 4 and 5). These motions
together with a simultaneous strong emission suggest that the early
chromospheric modifications, which may be considered as signatures
of flare precursor, are due to some in situ mechanisms. 6 seconds
after the peak time of the first HXR spike we determine a downward
velocity, ranging from 1km/s for the metallic lines up to 20km/s for
H<SUB>delta</SUB>_ and CaII K lines, for all the points of the slit
intersecting the H<SUB>alpha</SUB>_+1.5A kernel. According to the known
dynamic flare models, the measured velocity can be explained either by
direct heating of the chromosphere from non-thermal electrons with a
low energy cutoff of 10keV, or by a thermal conduction front from the
hot corona. The downward velocity continues to increase (roughly by a
factor of 2) for 10s after the end of the first HXR spike; none of the
existing models predicts a similar behavior. After the fourth HXR spike
the direction of the velocity changes over the H<SUB>alpha</SUB>_+1.5 A
kernel and two small regions (=~3" in size), can be distinguished. In
the first one a downward velocity of about 15km/s is derived for
H<SUB>delta</SUB>_ and CaII K lines simultaneously to a velocity
=~1km/s from the metallic lines. In the second area, the velocities
derived from H<SUB>delta</SUB>_ and CaII K lines are upward directed,
with values up to -40km/s, while the velocity derived from the metallic
lines is still downward directed, with values =~1km/s. The sudden onset
of an upward motion could be related to the development of a surge
well visible after the flare; probably only the higher chromospheric
layers supply material to the surge.
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Title: Minor Photospheric and Chromospheric Magnetic Activity and
Related Coronal Signatures
Authors: Cauzzi, G.; Falchi, A.; Falciani, R.; Hiei, E.; Smaldone,
L. A.
1996mpsa.conf..433C Altcode: 1996IAUCo.153..433C
No abstract at ADS
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Title: Active regions effects on global oscillation measurements.
Authors: Marmolino, C.; Oliviero, M.; Severino, G.; Smaldone, L. A.
1996joso.proc..160M Altcode:
No abstract at ADS
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Title: Coordinated observations of solar activity
phenomena. I. Multispectral study of an elementary flare.
Authors: Cauzzi, G.; Falchi, A.; Falciani, R.; Smaldone, L. A.;
Schwartz, R. A.; Hagyard, M.
1995A&A...299..611C Altcode:
In this paper we present a multispectral analysis of a small flare
which may be considered as a sequence of elementary bursts rather than a
collective flare phenomenon. A series of 5 short-lived (duration =~1-7s)
emission spikes are in fact observed in hard X-ray (HXR). The flare was
also observed in soft X-ray (SXR), with 3s temporal resolution, and in
the optical range with very high spatial (=~0.5") and temporal (2.7s)
resolutions. Sequences of filter images, in H<SUB>alpha</SUB>_ +1.5A,
He-D_3_ and Na-D_2_ wavelengths were acquired. The flare impulsive
phase, indicated by the occurrence of the HXR spikes, is preceded by
an enhancement in the chromospheric and in the coronal SXR emissions
starting, respectively, 40 and 15s before the flare. This indicates
that a density and/or a temperature increase in the flaring loop starts
at chromospheric levels, and only after this phase are the 5 separate
electron beams sequentially accelerated and stopped in an atmosphere
that is already modified. Four of the 5 HXR spikes are temporally
associated with chromospheric emission features over small areas of
3" size, while the fifth spike does not have detectable associated
signatures. Apparent contradictions between H<SUB>alpha</SUB>_ +
1.5 A and He-D_3_ emissions can be explained assuming atmospheric
inhomogeneities, already present within the flaring loop. The flare
occurs within an area of positive magnetic polarity, which shows a
moderate but constant weighted magnetic shear. No inclusions of the
opposite polarity are found in the flaring region, and no changes
in the distribution of any of the magnetic field parameters are
detected before, during and after the flare occurrence. No detectable
modifications are measured in the continuum and in all the wavelength
points of the Na-D_2_ line profile apart from the line core; this means
that flare-associated modifications of the flaring loop atmosphere do
not penetrate below the temperature minimum region.
---------------------------------------------------------
Title: Magnetic Noise Simulations in Velocity
Authors: Marmolino, C.; Oliviero, M.; Severino, G.; Smaldone, L. A.
1995ESASP.376b.407M Altcode: 1995help.confP.407M; 1995soho....2..407M
No abstract at ADS
---------------------------------------------------------
Title: Restored Solar Velocity Measurements Obtained from the May 10,
1994 Annular Solar Eclipse
Authors: Keil, S. L.; Balasubramaniam, K. S.; Ljungberg, S. K.;
Smaldone, L. A.; Rimmele, T. R.
1995SPD....26..202K Altcode: 1995BAAS...27..951K
No abstract at ADS
---------------------------------------------------------
Title: Dynamics of Small Flux Tubes
Authors: Reger, Bernard; Keil, Stephen L.; Smaldone, Luigi A.; Cauzzi,
Gianna; Balasubramaniam, K. S.
1994ASPC...68..157R Altcode: 1994sare.conf..157R
No abstract at ADS
---------------------------------------------------------
Title: Observations of Active Region Dynamics: Preflare Flows and
Field Observations
Authors: Keil, Stephen L.; Balasubramaniam, K. S.; Bernasconi, Pietro;
Smaldone, Luigi A.; Cauzzi, Gianna
1994ASPC...68..265K Altcode: 1994sare.conf..265K
No abstract at ADS
---------------------------------------------------------
Title: High temporal and spatial resolution observations of a solar
flare on June 7, 1991
Authors: Cauzzi, G.; Falchi, A.; Falciani, R.; Smaldone, L. A.
1993AdSpR..13i.311C Altcode: 1993AdSpR..13..311C
We present some preliminary results on a small flare observed at the
NSO-Sacramento Peak with very good spatial resolution (.6”-.7”). The
flare occurred on June, 7 1991 at ~ 13:43 UT in the NOAA region 6659
and has been observed by the COMPTON BATSE experiment in the 25-50 KeV
range. A very complex velocity pattern is found for chromospheric and
metallic lines: a small region (5” wide) presents a strong blue-shifts
in all these lines, lasting through the flare, while, only in the Ca
II-K and H<SUB>δ</SUB> lines, we find a zone (again ~ 5” wide) of
strong red asymmetries contemporary to the hard X-rays spikes. These
observations show the importance of having high spatial and temporal
resolution measurements in the study of flares.
---------------------------------------------------------
Title: On the calibration of line-of-sight magnetograms
Authors: Cauzzi, G.; Smaldone, L. A.; Balasubramaniam, K. S.; Keil,
S. L.
1993SoPh..146..207C Altcode:
Inference of magnetic fields from very high spatial, spectral, and
temporal resolution polarized images is critical in understanding the
physical processes that form and evolve fine scale structures in the
solar atmosphere. Studying high spectral resolution data also helps
in understanding the limits of lower resolution spectral data. We
compare three different methods for calibrating the line-of-sight
component of the magnetic field. Each method is tested for varying
degrees of spectral resolution on both synthetic line profiles computed
for known magnetic fields and real data. The methods evaluated are:
(a) the differences in the center of gravity of the right and left
circular components for different spectral resolution, (b) conversion
of circular polarization, at particular wavelengths, to magnetic
fields using model-dependent numerical solutions to the equations of
polarized radiative transfer, and (c) the derivative method using
the weak field approximation. Each method is applied to very high
spatial and spectral resolution circular polarization images of an
active region, acquired in the FeI 5250 å Zeeman-sensitive spectral
line. The images were obtained using the 20 må pass-band tunable
filter at NSO/Sacramento Peak Observatory Vacuum Tower Telescope. We
find that the center-of-gravity separation offers the best way of
inferring the longitudinal magnetic field.
---------------------------------------------------------
Title: Observation of solar flares at high resolution.
Authors: Cauzzi, G.; Falciani, R.; Falchi, A.; Smaldone, L. A.
1992ESASP.344..141C Altcode: 1992spai.rept..141C
The authors present some preliminary results of the observation of
a flare performed at the NSO-Sacramento Peak with very good spatial
resolution. The flare occurred on June 7, 1991 at ≡13:43 UT in the
NOAA region 6659, showing an unusual high activity. A small region,
≡3″wide, shows strong blue shifts (of the order of the sound
speed) in some metallic lines formed in the high photosphere, during
the flare impulsive phase. These observations show the importance of
having measurements at higher spatial and temporal resolution for an
effective improvement of the knowledge of the fundamental dynamic of
active regions and flares.
---------------------------------------------------------
Title: Analysis of the optical spectra of the solar
flares. VI. Velocity field in the 13 June 1980 flare area.
Authors: Falchi, A.; Falciani, R.; Smaldone, L. A.
1992A&A...256..255F Altcode:
The 13 June 1980 flare area was observed at NSO-Sacramento Peak
Observatory, simultaneously with the Universal Spectrograph and with the
Universal Birefringent Filter in parallel with the Zeiss H<SUB>α</SUB>
filter. The authors consider the flare emission measured with the
spectrograph in the H<SUB>β</SUB>, H<SUB>γ</SUB>, H<SUB>δ</SUB>,
Ca II-K and Na-D<SUB>2</SUB> lines to detect possible asymmetry
in their profiles. A characteristic blue asymmetry, indicative of
coronal upflows, is present in the Ca XIX spectrum obtained with
the Bent Crystal Spectrometer on the Solar Maximum Mission. This is
qualitatively consistent with the generally accepted scenario of a
chromophseric evaporation sufficiently rapid to drive both coronal
upflows and chromospheric downflows. The velocities obtained from
chromospheric lines are compared with the ones predicted by numerical
simulations of gas dynamics in flare loops (Fisher 1986, 1989). The
results show that the chromospheric condensation, predicted to be
moving downwards with constant velocity within the condensation,
probably has a velocity gradient and that the layers ahead of it seem
to be affected by the motion of the condensation.
---------------------------------------------------------
Title: Velocity Field in the 1980JUN13 Flare Area
Authors: Falchi, A.; Falciani, R.; Smaldone, L. A.
1992LNP...399..342F Altcode: 1992esf..coll..342F; 1992IAUCo.133..342F
No abstract at ADS
---------------------------------------------------------
Title: Narrow Bandpass Filter Solar Observations
Authors: Smaldone, L. A.; Cauzzi, G.; Keil, S. L.
1991BAAS...23.1057S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: High resolution spectropolarimetry of an active region.
Authors: Bonaccini, D.; Landi Degl'Innocenti, E.; Smaldone, L. A.;
Tamblyn, P.
1991sopo.work..251B Altcode:
Some spectropolarimetric observations at moderately high spatial
resolution are presented. The observations, obtained through a
Fabry-Perot interferometer in cascade of an Universal Birefringent
Filter, show the high potentiality of this spectroscopic technique
for the detailed analysis of solar active regions.
---------------------------------------------------------
Title: Needs and constraints for coordinated programs of photospheric
and chromospheric studies of flares
Authors: Falchi, A.; Falciani, R.; Smaldone, L. A.
1991AdSpR..11e..85F Altcode: 1991AdSpR..11...85F
Suggestions for a coordinated observing program of the photospheric and
chromospheric components of a flare are given; the maximum efficiency
can be reached only if simultaneous measurements of coronal emission
component may be obtained. The observing program has to be changed
according to the different characteristics of a flare in each phase of
its development. During the build-up phase it is of particular interest
to establish the correlation between the photospheric velocity field
(determined from bidimensional spectroscopic images in the 5576 Fe
I line) and the magnetic field. During the transient explosive phase
particular emphasys should be given to high time resolution observations
(at least 1 sec) in order to correlate the response of chromospheric and
photospheric signatures to the energy release producing the impusive
phase in the hard X-ray and microwave emission. Observations with
different filters in the center and red wing of the H<SUB>α</SUB>
line, in CN (0-0) band and in some continuous windows are suggested in
order to have time and spatial resolution as high as possible. Spectral
observations in the region 3400 - 4300 Å give the possibility to
measure the red shift of the Balmer lines presumably associated
to the chromospheric condensation moving downward. When the flare
atmosphere may be considered in pressure balance (after tens of
seconds) the time resolution is not crucial and the H<SUB>α</SUB>
and Na-D<SUB>2</SUB> line profile may be obtained with the Zeiss and
UBF filter used in bidimensional spectroscopic mode. H<SUB>α</SUB>
line gives the possibility to test the effect of the heating mechanism
while the Na-D<SUB>2</SUB> line is useful to monitor the penetration
depth of the flare disturbance.
---------------------------------------------------------
Title: Analysis of the optical spectra of solar flares. V -
Sensitivity of the hydrogen Balmer signatures and of the Na-D2 line
profile to different energy transport mechanisms
Authors: Falchi, A.; Falciani, R.; Smaldone, L. A.
1990A&AS...84..601F Altcode:
The effects of nonthermal electron flux, thermal conductive flux,
and coronal pressure on the behavior of spectral signatures are
investigated using various solar flare models. The method used
to derive the Balmer and Na-D2 is described. It is observed that:
a high value for the nonthermal electron flux is indicated by very
broad wings of the Balmer lines and a well developed pseudocontinuum
emission; a central emission reversal depicts a small coronal pressure
value; and an intense Balmer line combined with a very weak Balmer
continuum indicate a high coronal pressure value, but a low electron
flux value. Changes in the Na-D2 line are detected only in the core
of its profile. It is also detected that an increase in the conductive
flux over a threshold level decreases both lines, the Balmer continuum,
and the Na-D2 line core emission.
---------------------------------------------------------
Title: Two-Dimensional High-Resolution Spectroscopy of Quiet Regions
on the Sun
Authors: Bonaccini, D.; Cauzzi, G.; Falchi, A.; Falciani, R.; Smaldone,
L. A.
1990Ap&SS.170..117B Altcode:
We present preliminary results of solar bi-dimensional spectroscopy
observations obtained with the new 20 mÅ NSO-Sacramento Peak tunable
filter. The procedures of image destretching and the corrections for
the modulation of the 5-min oscillations are briefly discussed.
---------------------------------------------------------
Title: Anisotropies in solar oscillations
Authors: Caccin, B.; Fofi, M.; Torelli, M.; Smaldone, L. A.
1990A&A...232..516C Altcode:
Spherical harmonic filtering 20 less than or equal to l = m less than
or equal to 100 has been applied to analyze a time series of Doppler
observations in Na light in order to find eventual anisotropies
between sectorial modes propagating along east-west and north-south
directions. The results obtained show that the strongest power is
connected with the north-south direction and that the power ratio
NS/EW grows linearly with l.
---------------------------------------------------------
Title: Spectroscopic Observations of the dMe Flare Stars V1216 Sgr
and V 1054 Oph
Authors: Falchi, A.; Tozzi, G. P.; Falciani, F.; Smaldone, L. A.
1990ApL&C..28...15F Altcode: 1990ApL....28...15F
No abstract at ADS
---------------------------------------------------------
Title: Did an outburst occur on 4 December 1985 in Halley's comet?
Authors: Festou, M. C.; Tozzi, G. P.; Smaldone, L. A.; Felenbok, P.;
Falciani, R.; Zucconi, J. -M.
1990A&A...227..609F Altcode:
Two sets of complementary observations of large-amplitude brightness and
gas production rate variations on Comet Halley made on 4.2-4.9 December,
1985 by two very different techniques are interpreted here using the
atmospheric model of Festou (1981). The brightness observations are
found to be not consistent with production of parent molecules at a
steady rate. It is shown that a noticeable gas production increase
occurred shortly before the observations were made. The interpretation
of the OH line profile requires that the velocity of the parent
molecules be larger than 1 km/s. A possible explanation in terms of
a variable velocity of the H2O molecules is given.
---------------------------------------------------------
Title: Bi-dimensional solar spectroscopy with the 20 mÅ filter:
capabilities and constraints.
Authors: Cauzzi, Gianna; Smaldone, Luigi A.
1990SPIE.1318..193C Altcode:
A new technique to perform bi-dimensional solar spectroscopy,
by means of a narrow passband filter, is examined. The technique,
combining high spatial and spectral resolution observations, allows
the determination of the dynamic and thermodynamic parameters of the
observed solar features, their spatial relationships and their evolution
properties. The authors discuss this technique, its observational
constraints and the data reduction procedures.
---------------------------------------------------------
Title: Some remarks on the data analysis problems in solar
two-dimensional spectroscopy
Authors: Cauzzi, G.; Smaldone, L. A.; Bonaccini, D.; Falciani, R.
1989hsrs.conf..261C Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Flare model sensitivity of the Balmer spectrum
Authors: Falchi, A.; Falciani, R.; Smaldone, L. A.; Tozzi, G. P.
1989dots.work..183F Altcode:
Careful studies of various chromospheric spectral signatures are
very important in order to explore their possible sensitivity to the
modifications of the thermodynamic quantities produced by the flare
occurrence. Pioneer work of Canfield and co-workers have shown how
the H alpha behavior is able to indicate different changes in the
atmospheric parameters structure associated to the flare event. It
was decided to study the behavior of the highest Balmer lines and of
the Balmer continuum in different solar flare model atmospheres. These
spectral features, originating in the deep photosphere in a quiet area,
may have a sensitivity different from H alpha to the modification of a
flare atmosphere. The details of the method used to compute the Stark
profile of the higher Balmer line (n is greater than or equal to 6)
and their merging were extensively given elsewhere (Donati-Falchi et
al., 1985; Falchi et al., 1989). The models used were developed by
Ricchiazzi in his thesis (1982) evaluating the chromospheric response
to both the nonthermal electron flux, for energy greater than 20 kev,
(F<SUB>20)</SUB> and to the thermal conduction, (F<SUB>c).</SUB> The
effect of the coronal pressure values (P<SUB>O)</SUB> at the apex of
the flare loop is also included.
---------------------------------------------------------
Title: The evaluation of the Balmer merging effects in different
chromospheric solar flare models.
Authors: Falchi, A.; Falciani, R.; Smaldone, L. A.; Tozzi, G. P.
1989sasf.confP.345F Altcode: 1988sasf.conf..345F; 1989IAUCo.104P.345F
Synthetic spectra computed with semiempirical and theoretical
models of the flare atmosphere are discussed. Stark profile of the
Balmer lines (n ≥ 6) and the Balmer continuum have been computed
according to Donati-Falchi et al., (1985). A semiempirical model in
between the F2 and F3 models proposed by Avrett et al., (1986) might
represent a good approximation of the atmosphere of a flare during the
impulsive phase. Among the theoretical models proposed by Ricchiazzi
(1982), the model, indicated as 1073, with very high coronal pressure
(P<SUB>υ</SUB> = 1000 dyne cm<SUP>-2</SUP>) probably represents the
best approximation of the emission observed during the impulsive phase
of a chromospheric flare.
---------------------------------------------------------
Title: Balmer lines and continuum emission for two flares of the
dMe star Gliese 729.
Authors: Falchi, A.; Falciani, R.; Smaldone, L. A.; Tozzi, G. P.
1989sasf.confP..79F Altcode: 1989IAUCo.104P..79F; 1988sasf.conf...79F
It has been shown for solar flares (Donati-Falchi et al., 1985)
that the continuum emission at the Balmer discontinuity (the blue
"pseudo-continuum") is a very sensitive tool to determine the electron
density. In order to use the same interpretative scheme for stellar
flares (Falchi et al., 1988), spectroscopic observations of various
flare stars have been performed in June 1987 at ESO Observatory
(Chile). In this paper the authors report the analysis of spectra of
the star n. 729 (V1216 Sgr) of the Gliese catalog.
---------------------------------------------------------
Title: Bidimensional spectroscopy of network bright points
Authors: Falchi, A.; Falciani, R.; Smaldone, L. A.; Tozzi, G. P.
1988SoPh..114...29F Altcode:
We develop an automatic, computer controlled procedure to select and
to analyze the Network Bright Points (NBPs) on solar images. These
have been obtained at the Sac Peak Vacuum Tower Telescope by means
of the Universal Birefringent Filter and Zeiss Hα filters, tuned,
respectively, along the profiles of the Hβ, Mg-b1, Na-D2, and Hα
lines.
---------------------------------------------------------
Title: JOSO Working Group 3 - Italian Contribution to a Data Analysis
Package for Solar Physics
Authors: Smaldone, L. A.; Tozzi, G. P.
1988iaia.conf...31S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observational Maps of the Moments of Strong Line Profiles on
the Solar Disk
Authors: Caccin, B.; Donati-Falchi, A.; Falciani, R.; Smaldone, L. A.;
Tozzi, G. P.
1987SoPh..112..383C Altcode:
Using the method of solar bidimensional spectroscopy based on
the Universal Birefringent Filter (UBF), we have determined the
bidimensional maps of moments of some chromospheric lines. The
observational material, referring to a quiet region on the disk center,
have been acquired with the UBF of the NSO at Sacramento Peak on
Aug. 27,1985. In this note we present the work in progress and the
new observational aspects arising from this diagnostic method.
---------------------------------------------------------
Title: Bidimensional spectroscopy of network bright points. I -
Morphological properties
Authors: Falchi, A.; Falciani, R.; Tozzi, G. P.; Smaldone, L. A.
1987SoPh..114...29F Altcode:
An automatic computer-controlled method for the selection and
analysis of network bright points (NBPs) on solar images is proposed
which uses a universal birefringent filter (monitoring the H-beta,
Mg-b1, and Na-D2 lines) and a H-alpha Zeiss Filter (monitoring the
H-alpha line). Identification constraints are discussed, and various
parameters, including position, area, mean and maximum contrast,
Dopplergram velocity, and compactness, are measured for each NBP. Two
types of NBPs are identified, the more frequently occurring type Is
(found on the boundaries of the supergranular network) and the type IIs
(preferentially found in the neighborhood of small, compact sunspots).
---------------------------------------------------------
Title: Spatial distribution of neutral and ionized gas in the Halley
comet coma after the perihelion.
Authors: Falciani, R.; Festou, M.; Smaldone, L. A.; Tozzi, G. P.
1987PAICz..67...79F Altcode: 1987eram....2...79F
Long slit Halley comet spectra taken at ESO Observatory after the
perihelion have been analyzed. It has been shown that the comet
increased its gas production rate of a factor 3 on 22.9 March 1986,
then it decreased to half the 23.1 March 1986.
---------------------------------------------------------
Title: Spatial Asymmetries of Some Gas Emissions in the Head of
Halley's Comet
Authors: Falciani, R.; Festou, M.; Smaldone, L. A.; Tozzi, G. P.
1986ESASP.250c..75F Altcode: 1986ehc3.conf...75F
Long slit visible spectra of Halley comet were recorded on Oct. 18.98
- 19.23, Nov. 14.86 - 15.09 and Dec. 4.74 - 4.91, 1985, along the
sunward direction. The radial profiles of the absolute intensity
emitted by the most prominent visible gas bands (CN, C<SUB>2</SUB>,
C<SUB>3</SUB>, NH<SUB>2</SUB>) have been obtained after careful
reduction and elaboration of the spectra. These data have been
interpreted using the vectorial model. On Dec. 4, it was possible
to explain the measured radial profiles with the occurrence of two
outbursts: the first one starting 1.5 days before the observations with
an increase of the gas production rate of about an order of magnitude,
the second one starting 0.6 days before, with an increasing of about
20% of the actual production rate.
---------------------------------------------------------
Title: Optical spectroscopy of the coma of comet Halley at ESO.
Authors: Falciani, R.; Smaldone, L. A.; Tozzi, G. P.
1986Msngr..44...15F Altcode:
Using optical spectra (3550-6800 A) obtained with the 1.5-m University
of Bologna telescope for the preperihelion phase, and with the 1.52-m
ESO telescope for the postperihelion phase, the coma of Comet Halley
is studied. A total of 25 spectra were obtained with different slit
orientations and exposure times. The observed extension of the scattered
solar radiation implies a very extended dust component.
---------------------------------------------------------
Title: Interpretation of continuum emissions in white light flares.
Authors: Falchi, A. Donati; Falciani, R.; Smaldone, L. A.
1986lasf.conf..136F Altcode: 1986lasf.symp..136F; 1986lasf.conf..136D
The authors computed the spectrum emitted by a white light flare (WLF)
schematically represented by an isothermal and uniform hydrogen slab
of geometrical thickness h. They assumed, as continuum opacities, H-,
Hb-f and Hf-f and included the effect of the merging of the Stark
broadened profiles of the highest Balmer lines. They conclude that
the interpretation of WLF spectra based only on very few "continuum"
windows can be misleading. When feasible the analysis of the Balmer line
profiles have to be properly taken into account, because these lines
yield useful information to put efficient constraints on the set of
physical parameters capable to explain the observed continuum emission.
---------------------------------------------------------
Title: Bidimensional spectroscopy observations of the 13 June
1980 flare.
Authors: Donati-Falchi, A.; Falciani, R.; Smaldone, L. A.
1986lasf.conf...59D Altcode: 1986lasf.symp...59D
For two bright chromospheric kernels the authors determined a
penetration depth of the flare disturbance of the order of 500 km
above r<SUB>0</SUB> = 1.0 and T<SUB>e</SUB> = 7000K. The brighter
kernel seems to fit an uniform slab model with N<SUB>e</SUB> =
10<SUP>13</SUP>cm<SUP>-3</SUP> and geometrical thickness h = 150 km,
the weaker one with N<SUB>e</SUB> ≤ 6×10<SUP>12</SUP>cm<SUP>-3</SUP>
and h ≤ 10 km. The brighter kernel shows a downward motion of 12
km/sec at the time of the maximum development of the flare and seems
to be connected with a weaker kernel (visible in Na-D<SUB>2</SUB> and
showing also a downward motion of 11 km/sec) by means of an absorbing
loop (visible in He-D<SUB>3</SUB>). Three interacting chromospheric
loops are detected as absorbing structures in He-D<SUB>3</SUB>.
---------------------------------------------------------
Title: Analysis of the optical spectra of solar flares. IV - The
'blue' continuum of white light flares
Authors: Donati-Falchi, A.; Falciani, R.; Smaldone, L. A.
1985A&A...152..165D Altcode:
The "blue" continuum emission at λ < 4000 Å of white light flares
(WLF) has been interpreted as mainly due to the merging of the Stark
broadened profiles of the highest Balmer lines. Stark profiles have
been computed according to the deFeiter (1966) method, using the Griem
(1962) asymptotic expressions for the electron broadening parameter. A
homogeneous and isothermal model for the WLF has been used to compute
a grid of emitted spectra; the NLTE hydrogen level populations are
from deFeiter (1966). A satisfactory agreement between some computed
spectra and those measured for the June 4, 1980 WLF has been found.
---------------------------------------------------------
Title: Spatial and Spectral Distribution of Photospheric Bright Points
Authors: Donati-Falchi, A.; Falciani, R.; Smaldone, L. A.; Tozzi, G. P.
1985tphr.conf...91D Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Spatial and spectral distribution of photospheric bright
points.
Authors: Donati-Falchi, A.; Falciani, R.; Smaldone, L. A.; Tozzi, G. P.
1985MPARp.212...91D Altcode:
Spatial and spectral properties of isolated bright points (IBP) are
studied. The authors conclude that the present IBP's properties can be
produced by seeing effects on effective facular point characteristics.
---------------------------------------------------------
Title: Line Profiles and Longitudinal Velocity Field in Seeing
Limited Small-Scale Atmospheric Structures
Authors: Falchi, F.; Falciani, R.; Smaldone, L. A.
1985LNP...233..172F Altcode: 1985hrsp.proc..172F
No abstract at ADS
---------------------------------------------------------
Title: Analysis of solar flares optical spectra. III - The line
emission of the June 4, 1980 white light flare
Authors: Donati-Falchi, A.; Sambuco, A. M.; Smaldone, L. A.;
Falciani, R.
1984A&AS...55..425D Altcode:
The spectra of the white light flare of June 4, 1980 observed with
the Universal Spectrograph of the Sacramento Peak Observatory have
been presented in paper II of this series. The authors give here all
the parameters (central peak wavelength and intensity, width at half
maximum, total power radiated in the line and so on) obtained from
the line emission analysis for central part of the flare kernel.
---------------------------------------------------------
Title: Analysis of the optical spectra of solar flares. II - The
energetics of the June 4, 1980 white light flare
Authors: Donati-Falchi, A.; Smaldone, L. A.; Falciani, R.
1984A&A...131..256D Altcode:
The spectra of the white light flare of June 4, 1980 observed with the
Universal spectrograph at the Sacramento Peak Observatory, have been
carefully analyzed with the interactive reduction procedure referred to
in Paper I of this series. The spectra of the flare kernel (possibly
the real footpoint of the flaring magnetic loop) have been divided
into 6 different adjacent strips in order to determine the variation
of emissions within the kernel itself. The authors obtain the absolute
values of the continuum and line emission. The time evolution of the
energy radiated in the optical range by the flare is also obtained
and the total energy in the range 3600 - 5900 Å is estimated to be
1.35×10<SUP>30</SUP>erg between 225950 UT and 230447 UT.
---------------------------------------------------------
Title: Bidimensional spectroscopy of the solar chromosphere during
the maximum year
Authors: Caccin, B.; Falchi, A.; Falciani, R.; Roberti, G.; Smaldone,
L. A.
1984AdSpR...4g.215C Altcode: 1984AdSpR...4..215C
Our program was based on simultaneous observations of the same solar
region with the Universal Birefringent Filter (UBF) at the Vacuum
Tower Telescope (VTT) and with the Big Dome BD Universal Spectrograph
(USG). For the UBF images analysis we refer to the 13 June 1980 RG
2502/2511 (N12-E11) observations. Selected pictures present the line
profiles for Hα, H<SUB>β</SUB>, Mg-b<SUB>1</SUB> and Na-D<SUB>2</SUB>
at some interesting “pixels” of the analyzed AR. We present the
detailed photometric morphology of the observed active area and the
longitudinal velocity field pattern. A comparison with the corresponding
UVSP data is given.
---------------------------------------------------------
Title: Recommendations on post focus instrumentation for LEST.
Authors: Wöhl, H.; Huber, M. C. E.; Mein, P.; Smaldone, L.
1984LFTR....5.....W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Bidimensional Analysis of Solar Active Regions and Flares -
Part One - Imaging Spectroscopy with Universal Birefringent Filters
Authors: Caccin, B.; Falciani, R.; Roberti, G.; Sambuco, A. M.;
Smaldone, L. A.
1983SoPh...89..323C Altcode:
We describe a method of solar bidimensional spectroscopy exploiting
the performances of a Universal Birefringent Filter (UBF) like that
of the Sacramento Peak Observatory, which enable an estimate of the
profile of some chromospheric lines with moderate spectral resolution
(). The numerical inversion technique of Backus and Gilbert has been
used to retrieve the estimated line profiles; the capabilities of
the proposed method is fully analyzed with some numerical tests and
examples. Correction procedures for errors in the positions of the UBF
passband, random fluctuations of the exposure times and non-uniform
brightness distribution on the filtergrams are also presented. The
whole method has been tested on the recovery of quiet atmosphere line
profiles and the results derived for the Na D<SUB>2</SUB> line show
that the proposed method is completely suitable for many investigations
in solar physics.
---------------------------------------------------------
Title: Analysis of the optical spectra of solar flares. I - The
flare of April 30, 1976
Authors: Acampa, E.; Smaldone, L. A.; Sambuco, A. M.; Falciani, R.
1982A&AS...47..485A Altcode:
A novel interactive method for the reduction of solar flare spectra is
described which permits the determination of values in the continuum
emission of the flare, as well as such line emission parameters
as wavelength, line maximum emission intensity, halfwidth, total
emissivity within the line, and line identification. The procedure
has been tested on existing observational material, and results are
presented for the case of the April 30, 1976 flare spectra.
---------------------------------------------------------
Title: Digital processing of high resolution solar filtergrams.
Authors: Caccin, B.; Russo, P.; Smaldone, L. A.
1982MmSAI..53..287C Altcode:
The authors describe the techniques for digital processing of
high resolution solar filtergrams developed at the Naples ASTRONET
station. Preliminary results obtained with Hα filtergrams provided
by the Ottawa River Solar Observatory are presented.
---------------------------------------------------------
Title: Magnetic Fine-Structures and Granular Velocities
Authors: Caccin, B.; Falciani, R.; Gomez, M. T.; Marmolino, C.;
Roberti, G.; Severino, G.; Smaldone, L. A.
1981SSRv...29..373C Altcode:
In the last years we have gained some experience in the diagnostics
of small-scale structures, both on the interpretative and on the
observational point of view. We report here the conclusions and the
suggestions for future developments attained in two main fields of
interest.
---------------------------------------------------------
Title: Some Results Concerning the Automatic Photometry of
Photographic Chromospheric Images
Authors: Azzarelli, L.; Casalini, P. L.; Cerri, S.; Falciani, R.;
Roberti, G.; Smaldone, L. A.
1981SoPh...71..247A Altcode:
The results of an exploratory work on the use of a high-speed,
computer-controlled flying-spot for quantitative photometry of solar
Hα images are given. The used method is briefly illustrated and
applied to the study of the photometric structure and evolution of
some chromospheric active regions. Evolutive curves and isophotes for
the 27 October 1969 plages (McMath 10381 and 10385) are presented.
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Title: Interactive reduction of solar flare spectra
Authors: Acampa, E.; Falciani, R.; Sambuco, A. M.; Smaldone, L. A.
1980MmSAI..51..423A Altcode:
No abstract at ADS
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Title: Far infrared spectroscopy during ESA/NASA ASSESS II mission
Authors: Melchiorri, B.; Melchiorri, F.; Natale, V.; Falciani, R.;
Smaldone, L. A.; Bussoletti, E.
1978MmSAI..49...43M Altcode:
One of the seven experiments selected by ESA for the NASA/ESA ASSESS II
(Airborne Scientific Spacelab Experiment System Simulation, II) mission
is described. The objectives of this experiment include measurements of
the temperature distribution in the upper solar atmosphere, IR emission
and absorption in the upper atmosphere of earth, and the limit of
anisotropy in sky emission. The equipment used for these measurements
is discussed, and a rough ground-calibration spectrum is presented to
illustrate the performance of the equipment. It is noted that about 40
interferograms of the sun, more than 100 interferograms of terrestrial
atmospheric emission, and some 10 hr of data on sky-noise anisotropy
have been obtained to date.
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Title: Far infrared spectroscopy during ESA/NASA ASSESS II mission.
Authors: Melchiorri, B.; Melchiorri, F.; Natale, V.; Falciani, R.;
Smaldone, L. A.; Bussoletti, E.
1978ASIC...38...43M Altcode:
No abstract at ADS
