explanation blue bibcodes open ADS page with paths to full text
Author name code: marmolino
ADS astronomy entries on 2022-09-14
author:"Marmolino, Ciro"
---------------------------------------------------------
Title: Phase Differences and Gains between Intensity and Velocity
in Low-Degree Acoustic Modes Measured by SOHO
Authors: Jiménez, Antonio; Roca Cortés, Teodoro; Severino, Giuseppe;
Marmolino, Ciro
1999ApJ...525.1042J Altcode:
Helioseismic instruments aboard SOHO are making possible a more accurate
way of investigating the internal structure of the Sun. Making use of
the different techniques and characteristics of these instruments,
it is possible to measure solar oscillations as variations of the
photospheric velocity (GOLF, MDI) or as irradiance and radiance
fluctuations (VIRGO, MDI). Among the other advantages of observing solar
oscillations simultaneously with different instruments and techniques,
the study of velocity and irradiance measurements provides information
on nonadiabatic effects in the radiatively cooled solar atmosphere. The
thermodynamical properties of the atmosphere determine a phase shift
between intensity and velocity (downward positive) oscillations of
-90° in the case of an adiabatic atmosphere. Here we compute the phase
differences and gains between intensity and velocity acoustic modes
measured by SOHO to quantify the nonadiabatic degree of the solar
atmosphere. After correcting the observed phase differences of the
solar background influence, we find not exactly an adiabactic behavior,
but close to it. Finally, we compare our results with three different
theoretical models of the solar atmosphere, finding the best agreement
with a model that includes turbulent pressure associated with convection
and fluctuations of the superadiabatic temperature gradient. <P />Based
on observations with the VIRGO, GOLF, and MDI instruments on board SOHO.
---------------------------------------------------------
Title: Intensity-velocity phase relations in the l - ν diagram
Authors: Masiello, G.; Marmolino, C.
1998MmSAI..69..619M Altcode:
No abstract at ADS
---------------------------------------------------------
Title: A Review of Intensity-Velocity Phase Relations in the Solar
Atmosphere: Observations
Authors: Masiello, G.; Marmolino, C.; Straus, Th.
1998ESASP.418..261M Altcode: 1998soho....6..261M
It is well known that the observation of the frequencies of solar
oscillations is a powerful diagnostic of the solar interior. In the
same way, the Intensity-Velocity (I - V) phase differences are more
and more becoming an efficient tool to investigate the dynamics of
the solar atmosphere. Here we present an up-to-date review of observed
phase differences Phi<SUB>I-V</SUB>, as function of temporal frequency
(nu), of degree (l), and of height in the atmosphere (h). The workers
active in this field use different conventions and definitions. This
heterogeneity does not help in the interpretation of an observable
which has not yet been completely understood on theoretical grounds. We
suggest to use the notation which attributes positive values to the
phase difference when the intensity perturbation leads the velocity
perturbation, taken positive away from the Sun. In our opinion, this
choice is the more convenient when comparing observed and theoretical
phase differences. The collection of the observed results in a ”box”,
with edges nu, l, and h, reveals an almost coherent scenario and allows
to state what is missing from an observational point of view. For
example, are still missing, at every height in the atmosphere,
observations of phase differences for intermediate l values (~4
<= l <= ~100), while some depths in the atmosphere are little
explored. Different phase regimes can be identified in the l - ν
diagram and it is possible to follow their behavior with the height
in the atmosphere. Since, up to now, phase differences have been
discussed only in terms of atmospheric oscillations, the comparison
between theory and observation is still in its infancy and it is not
yet complete the identification of the different phase regimes with
different dynamic and atmospheric phenomena.
---------------------------------------------------------
Title: Phase spectra seen from space
Authors: Straus, Th.; Deubner, F. -L.; Fleck, B.; Marmolino, C.;
Severino, G.; Tarbell, T.
1998IAUS..185..455S Altcode:
We discuss preliminary results of a study of the dynamics of the solar
atmosphere including a first space based investigation of k-omega phase
difference spectra between velocity and intensity perturbations. The
data, including simultaneous line shift, line depth, and continuum
intensity measurements at disk center, have been obtained from a MDI
time series in its high resolution mode. Line depth and continuum
intensity are used to calculate the line intensity which is the more
frequently used parameter in phase difference studies. We compare the
results to ground based observations.
---------------------------------------------------------
Title: K-ϖ Phase Spectra Obtained from Space
Authors: Straus, Th.; Fleck, B.; Severino, G.; Deubner, F. -L.;
Marmolino, C.; Tarbell, T.
1998ESASP.417..293S Altcode: 1998cesh.conf..293S
No abstract at ADS
---------------------------------------------------------
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.
---------------------------------------------------------
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.
---------------------------------------------------------
Title: Preface
Authors: Cauzzi, G.; Marmolino, C.
1997MmSAI..68..359C Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The ARGO full Coverage Detector
Authors: Bacci, C.; Bartoli, B.; Barone, F.; Dai, Behzhong; Bernardini,
P.; Calloni, E.; Cardarelli, R.; Catalanotti, S.; Cavaliere, A.;
Cessaroni, F.; Xu, Chunxian; Creti, P.; Banzengluobu; D'Ettorre
Pizaaoli, B.; De Vincenzi, M.; Di Sciascio, G.; Cai, Dong; Grado, A.;
Yu, Guangce; Kuang, Haohuai; Jia, Hunayu; He, Huilin; He, Huihai; Guo,
Hongwei; Lee, Huidong; Iacovacci, M.; Iucci, N.; Li, Jinyu; Le, Meng;
Marmolino, C.; Manearella, G.; Mari, S. M.; Martello, D.; Morselli,
A.; Milano, L.; Oliviero, M.; PAdovani, P.; Panareo, M.; Parisi, M.;
Shen, Peiruo; Pistilli, P.; Saavedra, O.; Santonico, R.; Severino,
G.; Sparvolli, R.; Stanescu, C.; Storini, M.; Surdo, A.; Vernetto,
S.; Villoresi, G.; Zhao, Xin; Zhang, Xueyao; Jiang, Yinlin; Chen,
Yongzhong; Tan, Youheng; Fu, Yu; Feng, Zhenyong
1997ICRC....5..265B Altcode: 1997ICRC...25e.265B
No abstract at ADS
---------------------------------------------------------
Title: The inconstant Sun. Proceedings. 2nd Napoli Thinkshop on
Physics and Astrophysics, Napoli (Italy), 18 Mar 1996.
Authors: Cauzzi, G.; Marmolino, C.
1997MmSAI..68..355C Altcode:
This Thinkshop addresses the problem of the contribution that solar
physics can give to modern physics and astrophysics.
---------------------------------------------------------
Title: ARTHEMIS: The Archive Project for the IPM and THEMIS
Authors: Reardon, K.; Severino, G.; Cauzzi, G.; Gomez, M. T.; Straus,
T.; Russo, G.; Smaldone, G.; Marmolino, C.
1997ASPC..118..398R Altcode: 1997fasp.conf..398R
We describe the plan for ARTHEMIS, the italian archive for THEMIS, from
the point of view of the prospective users of the archive. This archive
is designed to store the data from the Italian Panoramic Monochromator
(IPM) instrument installed on THEMIS as well as the full-disk images
obtained by the telescope. We break the expected users down into
seven categories: a) prospective IPM users; b) campaign planners; c)
data analysts, d) external collaborators; e) instrument monitors, f)
archival observers; and g) the general public.
---------------------------------------------------------
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
---------------------------------------------------------
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
---------------------------------------------------------
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
---------------------------------------------------------
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: Phases and amplitudes of acoustic-gravity waves. 2: The
effects of reflection
Authors: Marmolino, C.; Severino, G.; Deubner, F. -L.; Fleck, B.
1993A&A...278..617M Altcode:
We study wave reflection caused by the temperature stratification
of the solar atmosphere, assumed to be a succession of two layers
of different temperatures and radiative decay times. Considering
waves which propagate energy upward in the atmosphere, we compute
the complex amplitude reflection and transmission coefficients and
investigate the effects that reflection introduces on the phases of
acoustic-gravity waves. In the evanescent region of the k<SUB>x</SUB>
- omega diagram, between the Lamb waves and the acoustic cut-off
frequency, the reflection coefficient is small, in particular zero on
the fundamental mode. Therefore, in this region, the reflected wave
has a small amplitude and its superposition to the incident wave does
not affect the latter in a significant way. In particular, the T - V
phase differences of the total wave are very similar to those of the
incident wave. Furthermore, a heruisitic formula is presented which
describes the observed coexistence of two different phase regimes
between velocity and intensity oscillations in the evanescent area
above the fundamental mode.
---------------------------------------------------------
Title: Solar astronomy: the GOLF experiment on board of SOHO
Authors: Severino, G.; Gomez, M. T.; Andretta, V.; Marmolino, C.
1993MmSAI..64..790S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The center-to-limb variations of four Ca i lines in the
photospheric spectrum at λ6500
Authors: Ambruoso, P.; Marmolino, C.; Gomez, M. T.; Severino, G.
1992SoPh..141...35A Altcode:
We study the center-limb (CL) variation of the average profiles of four
Ca I lines near λ6500 and compare these observations with synthetic
data obtained from several line formation models having different
thermal structures, line parameters, LTE and non-LTE conditions,
and micro and macroturbulence values, to assess the formation
characteristics of our Ca I lines in the solar photosphere.
---------------------------------------------------------
Title: Phases and amplitudes of acoustic-gravity waves. I - Upward
and downward solutions
Authors: Marmolino, C.; Severino, G.
1991A&A...242..271M Altcode:
A study is presented of the phases and amplitudes of acoustic-gravity
waves in the kx-omega diagram. Waves which propagate energy both upward
and downward in the solar atmosphere are considered. The wave model
considers linear perturbations in a compressible medium assumed to be
a perfect gas stably stratified at uniform temperature and radiatively
damped. The kx-omega diagrams are also displayed for the temperature
and pressure amplitudes relative to velocity. The results from the
model are discussed and compared with recent observations of the phase
relations between velocity and brightness oscillations.
---------------------------------------------------------
Title: Dynamics of the solar atmosphere. IV - Evanescent waves of
small amplitude
Authors: Deubner, F. -L.; Fleck, B.; Marmolino, C.; Severino, G.
1990A&A...236..509D Altcode:
The phase spectra of velocity and brightness perturbations in the quiet
photosphere have been studied in the evanescent domain of the k-omega
diagram. A regime of low-amplitude evanescent motions, occupying a
large sector of the diagnostic diagram bordered by the Lamb and the
fundamental mode, has been discovered. This regime forms a continuum
in the k-omega plane, in contrast to the 5-min oscillations. Beyond the
fundamental mode, it extends to much higher frequencies in between the
power ridges of the resonant p-modes. It is suggested that the observed
V-I phase is characteristic of evanescent waves, whose progressive
part carries energy downward, and that a continuum of such waves is
produced through scattering of ordinary resonant p-modes at higher
levels in the atmosphere.
---------------------------------------------------------
Title: On the 5-MINUTE Photospheric Oscillation and its Modeling
Authors: Marmolino, C.; Severino, G.
1990IAUS..138..251M Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Wave Behavior in the Solar Photosphere - a Comparison of
Theory and Observation
Authors: Marmolino, Ciro; Stebbins, Robin T.
1989SoPh..124...23M Altcode:
We report detailed comparisons between theoretical and empirical
eigenfunctions of velocity and intensity for the 5-min modes in the
photosphere. The comparison process is accomplished by obtaining
synthetic profiles of the FeI λ5434 Å line in the presence
of waveforms given by dynamical calculations and then applying
a common procedure of reduction both to the observed and to the
synthetic data. For the velocity waveforms, our results show a general
agreement between theory and observations together with some systematic
differences; in particular the theory systematically underestimates the
observations in the low photosphere. These systematic differences are
stressed by the intensity results since both the computed amplitudes
and phases appear to be wrong in the deeper layers.
---------------------------------------------------------
Title: The signature of the 5-minute photospheric oscillation on
the solar spectral line profiles
Authors: Marmolino, C.; Severino, G.
1989MmSAI..60..181M Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observation and Interpretation of Photospheric Line Asymmetry
Changes near Active Regions
Authors: Keil, S. L.; Roudier, Th.; Cambell, E.; Koo, B. C.;
Marmolino, C.
1989ASIC..263..273K Altcode: 1989ssg..conf..273K
No abstract at ADS
---------------------------------------------------------
Title: The 5-minute oscillation in the solar photosphere - Theoretical
behaviour versus observations
Authors: Marmolino, C.; Stebbins, R. T.
1989MmSAI..60...71M Altcode:
Calculations are used to explore how theoretical waveforms for the
five-minute solar oscillation reproduce the observed behavior of
the solar Fe I 5434 A line. Comparison of theoretical and empirical
velocity eigenfunctions shows some systematic differences in a framework
of general agreement. The theory systematically underestimates the
observations in both amplitude and phase shift in the low photosphere;
the differences between the various theoretical treatments is much
smaller than the difference between theory and observation. The
intensity agreement is poor, with the theoretical treatments again
differing much less with each other than with observation. These results
are evidence for systematic problems with the assumptions involved in
the calculation of the waveforms pertaining to the deeper layers of
the photosphere.
---------------------------------------------------------
Title: Fe II lines in the presence of photospheric oscillations
Authors: Marmolino, C.; Roberti, G.; Severino, G.
1988ASSL..138..217M Altcode: 1988pffl.proc..217M; 1988IAUCo..94..217M
The synthesis of the Fe II 6516 A line in the solar photosphere in the
presence of granulation and five-minute oscillation is described. The
asymmetry of the spatially resolved profiles in the presence of
granulation is much stronger than that of the mean, unresolved
profile. There is a blueshift of the spatially averaged line profile
corresponding to a velocity of 360 m/s in the center of gravity. The
line bisector produced by the five-minute oscillation are plotted as
a function of time. When both granulation and five-minute oscillation
are present, the general behavior of the spatially averaged line
bisector vs. time is just the temporal fluctuation of the spatially
mean C-shape due to the granulation. When granulation is present, the
blue flank in the line profiles oscillates with a velocity amplitude
lower than the red flank does.
---------------------------------------------------------
Title: Temporal variations of solar spectral line profiles induced
by the 5-minute photospheric oscillation
Authors: Gomez, M. T.; Severino, G.; Marmolino, C.; Roberti, G.
1987A&A...188..169G Altcode:
The authors simulated the variations induced by the 5 min photospheric
oscillation on the line profiles. They found that a phase lag of the
order of 150 degree between temperature and velocity wave perturbations
can explain the observed differences between the oscillations of the
line flanks at residual intensity levels I/I<SUB>c</SUB> < 0.7. Such
a phase relation in the 5 min oscillation differs from that of the
adiabatic case in which the temperature and pressure fluctuations are 90
degrees out of phase with respect to the velocity. It is shown that a
simple model of radiative damping in the solar photosphere can produce
the required phase lag between temperature and velocity. Finally,
it is also shown that the granulation can affect differentially the
oscillations of the line flanks. This effect, however, does not fit
the observed behaviour of the flank oscillations.
---------------------------------------------------------
Title: Effects of acoustic and gravity waves on the curve of growth
Authors: Marmolino, C.
1987SoPh..112..211M Altcode:
Unresolved motions, or `microturbulence', play a very important role in
determining the Doppler width of the line-absorption coefficient. The
concept of microturbulence was introduced because observed solar and
stellar lines are broader than is explicable within the framework of
other line-broadening mechanisms. By constructing a curve-of-growth in
the presence of a dynamical model for simple acoustic and gravity waves,
this paper evaluates the errors introduced by the use of kinematic
models for line-broadening (microturbulence) into the determinations of
non-thermal velocity fields and element abundances. Distinct differences
between gravity and acoustic waves are apparent in the trend of the line
asymmetry with the excitation potential as well as in the magnitude
of the errors introduced by the temperature and pressure variations
associated with the velocity field.
---------------------------------------------------------
Title: Broadening and shift of Fe i lines perturbed by atomic
hydrogen
Authors: Gomez, M. T.; Marmolino, C.; Roberti, G.; Severino, G.
1987SoPh..112..227G Altcode:
The broadening and shift parameters for a number of FeI lines perturbed
by atomic hydrogen are computed using the interatomic potential due to
Hindmarsh et al. (1967, 1970). It is also shown that the rms radius
and the effective radius of the radiating atom, which determine the
force constants in the interatomic potential, can be simply related
each other, depending on the orbital quantum number of the atomic level.
---------------------------------------------------------
Title: Line asymmetries and shifts in the presence of granulation
and oscillations: The CLV of the K i 7699 resonance line
Authors: Marmolino, C.; Roberti, G.; Severino, G.
1987SoPh..108...21M Altcode:
We study the effects of both the solar granulation and short-period
oscillations on the solar profile of the KI 7699 resonance line and
its center-to-limb variations.
---------------------------------------------------------
Title: On the Differences between Line Bisectors in Quiet and
Active Sun
Authors: Marmolino, C.; Roberti, G.; Severino, G.
1987rfsm.conf...30M Altcode:
The asymmetry and shift of solar lines show systematic variations
between quiet and active regions. Marmolino et al. (1984, 1986) studied
the effects produced by photospheric motions (waves and granulation)
on the K I 7699 Å line in the quiet Sun. In this paper the authors
extend this study to the synthesis of line bisectors in plages.
---------------------------------------------------------
Title: Diagnostics for Propagating Waves in the Solar Photosphere
Authors: Keil, Stephen L.; Marmolino, Ciro
1986ApJ...310..912K Altcode:
The effects of pure acoustic waves of different frequencies on a
number of Fe I lines formed in the photosphere are investigated. A
dynamical model of the waves which considers velocity, temperature, and
pressure fluctuations as functions of time is used to compute the line
profiles. The extent to which the waves cause the lines to fluctuate,
the time-averaged properties of the line profiles, and the measurability
of vertical phase differences are all determined as functions of the
frequency of the propagating wave. It is concluded that there is no
intrinsic radiative limit, for frequencies of current observational
interest, on ability to measure phase differences. The asymmetry induced
by the propagation of acoustic waves in the photosphere is found to
depend on the frequency of the waves. Acoustic waves contribute only
marginally to line broadening.
---------------------------------------------------------
Title: The effects of acoustic-gravity waves on the K i 7699 line
Authors: Severino, G.; Roberti, G.; Marmolino, C.; Gomez, M. T.
1986SoPh..104..259S Altcode:
We examine the effects of acoustic-gravity waves with long and short
periods on the solar profile of the K I7699 line using a dynamic model
of line formation.
---------------------------------------------------------
Title: The Effects of Acoustic Waves on the Curve of Growth
Authors: Marmolino, C.
1986BAAS...18Q.663M Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Line Asymmetries and Shifts in Presence of Granulation and
Oscillations - the CLV of the KI7699 Resonance Line
Authors: Marmolino, C.; Roberti, G.; Severino, G.
1985tphr.conf...89M Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Line asymmetries and shifts in presence of granulation and
oscillations: the CLV of the K I 7699 resonance line.
Authors: Marmolino, C.; Roberti, G.; Severino, G.
1985MPARp.212...89M Altcode:
The authors study the effects of both the solar granulation and a
monochromatic acoustic-gravity wave on the solar profile of the K I
7699 resonance line and its center-to-limb variations (CLV).
---------------------------------------------------------
Title: The response of the line KI 7699 to the solar oscillations
Authors: Marmolino, C.; Roberti, G.; Severino, G.; Vazquez, M.;
Woehl, H.
1984ESASP.220..191M Altcode: 1984ESPM....4..191M
The time behavior of the KI 7699 line profile in presence of
acoustic-gravity waves with periods of 300, 180, and 30 sec was
studied. The response of the line to the waves depends strongly on
the period and is not linear for the 30 sec wave. The height increase
of the amplitude in the longer period waves explains the observed
anticorrelation between line asymmetry and line core shift. The time
averaged profile for the 30 sec wave has a red shifted line core. This
could account for the lowest part of the C shaped solar bisectors.
---------------------------------------------------------
Title: CA II K emission diagnostics. I - The widths and the strengths
in a one-dimensional model
Authors: Marmolino, C.; Severino, G.
1983A&A...127...33M Altcode:
The authors modeled the widths and the strengths of the Ca II K
emission from a one-dimensional atmosphere in terms of a limited set of
parameters. Partial frequency redistribution (PRD) in the scattering
process was correctly accounted for. The emission characteristics
depend generally on several model parameters. However the dependence
on chromospheric microturbulence appears to fit easily the observed
behaviour of the K<SUB>2</SUB> peak separation, W<SUB>2</SUB>, and of
the full width at half-maximum, W<SUB>0</SUB>. The authors remark that
emission in the core of the K line can occur as a PRD effect, without
any chromospheric temperature rise, and discuss some implications of
this event.
---------------------------------------------------------
Title: Detection of Propagating Waves in the Solar Photosphere
Authors: Keil, S. L.; Marmolino, C.
1983BAAS...15Q.971K Altcode:
No abstract at ADS
---------------------------------------------------------
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: The third central moment of photospheric lines as a measure
of velocity gradients and line shifts
Authors: Marmolino, C.; Severino, G.
1981A&A...100..191M Altcode:
The significance of the third central moment (M3) of photospheric
line profiles as an indicator of velocity, temperature and pressure
perturbations is analyzed. A linear inversion method is applied to the
third central moments of a set of synthetic lines computed using the
temperature structures of the B2 and D2 models of Altrock and Musman
(1976) for the granular and intergranular atmospheres, respectively,
in order to derive mean photospheric velocity gradients. It is found
that for data taken with infinite spatial resolution, M3 is a nearly
linear measure of the velocity gradients, whereas at finite resolution
it is essentially determined by the different weights of the shifted
granular and intergranular line components. Results also suggest a
means of disentangling velocity gradients and the horizontal integration
of inhomogeneities.
---------------------------------------------------------
Title: On the retrieval of velocity gradients from photospheric line
asymmetries - A linearized approach
Authors: Caccin, B.; Marmolino, C.
1980A&A....83...73C Altcode:
The first-order effects of a velocity field on the asymmetry of
Fraunhofer lines are analyzed and a method for recovering the velocity
gradient from the observed asymmetries is described. The method -
which does not require the concept of formation depth - is applied
to the inversion of synthetic data; the results obtained show that it
has the properties of stability and sensitivity necessary for working
in practice within a fairly large range of photospheric velocities
(up to the order of the Doppler width of the lines).
---------------------------------------------------------
Title: Determinazione dei gradienti di velocità nella fotosfera
solare dalle asimmetrie delle righe di Fraunhofer: un approccio
lineare.
Authors: Caccin, B.; Marmolino, C.
1979RSAI...22..146C Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Response functions and contribution functions of photospheric
lines.
Authors: Caccin, B.; Gomez, M. T.; Marmolino, C.; Severino, G.
1977A&A....54..227C Altcode:
An attempt is made to obtain the response function (RF) of a
photospheric Fraunhofer line by solving the equation of radiative
transfer in LTE using an appropriate perturbation method. A first-order
expression for the RF is derived with which effects of arbitrary
perturbations in thermodynamic quantities or velocity-field parameters
on emergent line intensity can be evaluated. Perturbations considered
to be amenable to such treatment include line-opacity Doppler shifts
due to velocity fields, microturbulence variations, and temperature
variations at constant electron density. Some examples of RFs for
photospheric lines are presented, and an attempt is made to define
the contribution function (CF) of a line depression in full analogy
with that of the emergent intensity. It is noted that a CF should not
be employed in place of the appropriate RF to predict the sensitivity
of a Fraunhofer line to a perturbation at a given depth.
