Résumés des programmes français du Science Team de FUSE
FUSE French Guaranteed Time Observing Programs (Cycles 1, 2, and 3)
----------------------------------------------------------------------------
Prog ID: Q101
Title: H_2 Associated with Dust Color Variations
PI: Gry
Institution: Laboratoire d'Astrophysique de Marseille and ISO Data Center
We propose to study the H_2 excitation, as well as the H_2 abundance and
velocity distribution in nearby diffuse clouds in the Chamaeleon complex.
The selected lines of sight present a wide variety in infrared colors,
E(B-V), Rv and molecular abundances so that we can check the dependence of
H_2 properties with these characteristics. After IRAS data revealed
spatial variations in the dust emission color of these clouds, these
variations have been correlated with changes in the shape of the UV part of
the extinction curve, showing that they are due to variations in the size
distribution of small dust particles. Comparative studies in the
millimeter, visible and UV ranges have shown that highly energetic
processes are present in the cloud presenting mid-IR excess.
Magnetohydrodynamic shocks and intermittent dissipation of turbulence have
been considered. The proposed study of H_2 in these clouds will help
characterize these processes which should be of great significance for the
evolution of dust particles and of the gas itself.
----------------------------------------------------------------------------
Prog ID: Q103
Title: He I in Local ISM
PI: Vidal-Madjar
Institution: Institut d'Astrophysique de Paris
An attempt will be made on the brightest EUVE source showing emission in
the 600 Angstrom EUVE band (410 c/ksec), to try to detect some second order
absorption signature corresponding to He I in the local ISM.
----------------------------------------------------------------------------
Prog ID: Q105
Title: Lyman Break in Star-Forming Galaxies
PI: Deharveng
Institution: Laboratoire d'Astronomie Spatiale
We wish to observe a star-forming galaxy shortward of its (rest frame)
Lyman limit in order to measure or set limits on the Lyman continuum escape
fraction. An object with a redshift large enough to get rid of residual
galactic gas absorption (lyman series) is selected. Another related goal
is to use the spectrum longward of the Lyman limit for better understanding
the star, dust and gas content of the galaxy.
----------------------------------------------------------------------------
Prog ID: Q106
Title: O VI Phase in Galactic Haloes
PI: LeBrun
Institution: Laboratoire d'Astronomie Spatiale
We propose to make low resolution (R=2000 and S/N~20) observations of two
quasars, 3C 351 and Mark 205. Their sightlines cross the near environment
of already known and identified galaxies or groups of galaxies, at impact
parameters in the range 40-700 kpc (H0 = 50 km/s/Mpc). We will be able to
detect the O VI doublet lines in absorption down to a limiting equivalent
width of 0.2 Angstrom. We thus plan to determine whether a highly ionized
phase exists in the close galactic environment in which the cooler and
denser MgII absorbers would be embedded. These observations will also help
in determining whether collisional excitation is present in these clouds
and also to study the evolution of the shape and intensity of the
intergalactic UV flux at low redshift.
----------------------------------------------------------------------------
Prog ID: Q107
Title: H_2 in the Small Magellanic Cloud
PI: Ferlet
Institution: Institut d'Astrophysique de Paris
The star Sk 143 in the SMC has most peculiar properties: its extinction
curve in the far-UV is of Galactic type, contrary to all the other SMC
stars which have a small or absent extinction bump and a very strong rise in
the extinction at shorter wavelength. It also has an apparently Galactic ratio
of E(B-V) to atomic hydrogen column density. Still, the interstellar lines are
at the SMC velocity, and suggest that the extinction is due to a molecular
cloud in the SMC. However a deep integration in the CO(1-0) line with the
Swedish-ESO submillimeter telescope has given a null result. FUSE will help
solve this mystery by observing the H_2 lines and other lines which might
yield a detection of the absorbing gas.
----------------------------------------------------------------------------
Prog ID: Q108
Title: Central Stars of Planetary Nebulae
PI: Vidal-Madjar
Institution: Institut d'Astrophysique de Paris
Several investigations will be done simultaneously by observing the central
stars of some bright Planetary Nebulae (PN):
(a)The wavelength range is particularly appropriate to study the continuum,
the temperature and the wind of the PNe central stars;
(b)In addition to the stellar continuum, the spectra will yield information
concerning the nebula. The CIII line at 977A should be easily observable.
Its intensity will be an additional independent measurement to resolve
the controversy about the carbon abundance in PN;
(c)FUSE will offer the possibility to detect molecular hydrogen
lines in absorption against the stellar continuum. In several cases,
the velocity separation of that component formed in the vicinity of the
nebula and that formed in the general ISM will be possible. It should
then be possible to determine how much additionnal H_2 is formed by
shocks in the stellar winds.
(d)Finally, the non detection of deuterium should allow a direct check of its
evolution within stars since these PN were selected for their different 3He
environment.
----------------------------------------------------------------------------
Prog ID: Q109
Title: Peculiar White Dwarfs
PI: Vidal-Madjar
Institution: Institut d'Astrophysique de Paris
The standard post-AGB evolution theory predicts that throughout the
whole post-AGB phases the chemical surface composition of the star remains
essentially unchanged, because hydrogen shell burning ceases when the
surface H-rich layer has been thinned down to about 1.e-4 Msun. However
about 25% of the spectroscopically observed post-AGB stars in the planetary
nebula stage are hydrogen-deficient and the origin of their peculiar
surface abundances is still unclear. Among the hydrogen deficient post-AGB
stars the class of the PG1159 stars are the most peculiar. They cover the
hottest part of the post-AGB evolution (65000 - 180000K) and their surface
is composed of carbon, helium, and oxygen (typically 50/30/20% by mass).
Since mass loss could also be responsible for the observed peculiarities,
we need a determination of the mass-loss rate to be conclusive. The O VI
line at 1034 Angstroms is best suited since it is the most sensitive
indicator for mass-loss in these stars. In that frame we will observe
PG1159-035 the prototype as well as H1504+65 which is the most extreme one
of this class. Deuterium evaluations will be also made on the line of
sights towards these stars.
----------------------------------------------------------------------------
Prog ID: Q110
Title: Quasi-Molecular Satellite Lines in Lyman Beta
PI: Vidal-Madjar
Institution: Institut d'Astrophysique de Paris
Our purpose is to detect in the wing of Lyman Beta the signatures of
absorptions due to the quasimolecular satellites of H_2+ and H_2 in,
respectively, photospheric spectra of a white dwarf and a Lambda Boo star
where they have been observed in wing of Lyman Alpha. These targets are
suitable for such detection: the white dwarf WD1620-391 has a pure hydrogen
atmosphere and that of HD125162 is depleted in metals.
----------------------------------------------------------------------------
Prog ID: Q111
Title: The Symbiotic Binary IX Velorum
PI: Ferlet
Institution: Institut d'Astrophysique de Paris
The profiles of the absorption and emission lines, particularly of the O VI
doublet for the symbiotic binary AG Peg, will enable information to be
obtained on the kinematics of the regions of line formation. The very high
ionization O VI doublet may in particular be produced very near the compact
hot component. A wind from the cool component of the binary should be
present; signs of the continuing existence of a wind from the hot component
seen on older IUE spectra as well as a possible region where the winds
collide, will be looked for.
----------------------------------------------------------------------------
Prog ID: Q112
Title: Cataclysmic Binaries
PI: Ferlet
Institution: Institut d'Astrophysique de Paris
We propose to observe the highly mass-accreting cataclysmic binary IX Vel
in the far UV, for the first time at a very high spectral resolution
(R~30000), to infer the physics of the accretion very close to the white
dwarf. A detailed analysis of the absorption resonance lines of O VI, PV
and SVI by means of phase-resolved spectra (exposure time of 1/8 Porbital)
will bring important clues to probe the structure of the wind (geometry,
velocity law, inhomogeneities). When combined with the study of the
continuum distribution in the far UV, this will allow us to test the still
unknown mechanism of wind formation and to distinguish between different
proposed models for the boundary layer which plays a major role in the
dynamical evolution of these systems.
----------------------------------------------------------------------------
Prog ID: Q113
Title: The Old Nova V603 Aql
PI: Ferlet
Institution: Institut d'Astrophysique de Paris
The absorption and emission line profiles of the old nova V603 Aql will
be observed with FUSE in order to further study the properties of what
appear to be an accretion disk and wind coming from this disk, also studied
at longer wavelengths. Rapid line profile variations already seen for
other lines in HST spectra, will in be searched for and examined, this
being the case in particular for the O VI doublet.
----------------------------------------------------------------------------
Prog ID: Q114
Title: Be Stars
PI: Ferlet
Institution: Institut d'Astrophysique de Paris
The study of high excitation line transitions in the wavelength range
observed by FUSE will bring important information on the nature of
activities taking place in the outermost layers of Be stars. The Lyman
energy distribution predicted by thermal models of stellar atmospheres,
which does not even agree with observations of normal B stars, will
probably produce larger disagreements in Be stars, where, as highly
rotating objects, the atmospheric structure remains quite unknown. A young
B star in a binary system with a T-Tauri star will also be observed for the
purpose of comparison. This program is also conducted in the frame of
other observing programs toward B and Be stars.
----------------------------------------------------------------------------
Prog ID: Q119
Title: Circumstellar Disks
PI: Deleuil
The purpose of this program is to give new insights on the signatures of
circumstellar gas around main-sequence and pre-main-sequence stars. For
the stars Beta Pic (HD39060) and 51 Oph (HD158643), the gas already
detected may be the by-product of some activity (like evaporation and/or
collision of kilometer-sized bodies) in a young planetary system in its
clearing out phase. These observations are expected to allow the
identification of the main form of the gaseous phase (H_2, CO, OI, NI, CII
?) and to give information on the ionization equilibrium of the zero radial
velocity as well as accreting gas. Analysis of multiplet ratios will allow
to probe the sizes of the inflowing gas structures.
----------------------------------------------------------------------------
Prog ID: Q201
PI: Gry, Cecile
Institution: Laboratoire d'Astrophysique de Marseille and ISO Data Center
Title: IS Studies : H2 associated with dust color variations
We propose to study the H2 excitation, as well as the H2 abundance and
velocity distribution in nearby diffuse clouds.
This is to complement the study started with Q101 for clouds in
the Chamaeleon complex.
The selected lines of sight present a wide variety in infrared colors,
E(B-V), Rv and molecular abundances so that we can check for correlations
between these characteristics and H2 properties.
After IRAS data have evidenced spatial variations in the dust emission
color of these clouds, these variations have been correlated with changes
in the shape of the UV part of the extinction curve, showing that they are
due to variations in the size distribution of small dust particles.
Comparative studies in the millimeter, visible and UV ranges have shown
that highly energetic processes are present in the cloud presenting mid-IR
excess. Magnetohydrodynamic shocks and intermittent dissipation of turbulence
have been considered. The proposed study of H2 in these clouds will help
characterize these processes which should be of great significance for the
evolution of dust particles and of the gas itself.
----------------------------------------------------------------------------
Prog ID: Q206
PI: Le Brun, Vincent
Institution: Laboratoire d'Astronomie Spatiale
Title: O VI Phase in Galactic Haloes
This program is the continuation of the Q106 program on the study of the
OVI phase in galactic halos. We have selected a third quasar, Q0026+1259
(Bowen & Blades, 1997). Two galaxies lie close to the quasar sightline,
which could give rise to OVI absorption lines, which FUSE only would be
able to detect. The quasars has a flux of 2x10^-14 erg/s/cm^2/A.
----------------------------------------------------------------------------
Prog ID: Q210
PI: Hebrard, Guillaume
Institution: Institut d'Astrophysique de Paris
Title: Quasi-Molecular Satellite Lines in Lyman Beta
Quasi-molecular satellites provide an important source of opacity in
the DA white dwarf atmospheres not only in the red wing of Lyman alpha,
but also in the red wing of Lyman beta. The recently discovered line
satellites in the red wing of Lyman beta due to the close collisions of
atomic hydrogen with protons fall right on the range of maximum
sensitivity of FUSE (1050 - 1100 A). This spectrum region has a
great potential for determining basic stellar parameters, provided
that the physics underlying its formation is well described. This is
exactly what we are able to achieve. We propose to observe one DA
cool white dwarf in order to study the temperature
sensitivity of the Lyman beta spectrum and deduce the lower limit of
appearence of these line satellites.
----------------------------------------------------------------------------
Prog ID: Q219
PI: Lecavelier, Alain
Institution: CNES, Institut d'Astrophysique de Paris
Title: Circumstellar Disks
The purpose of this program is to obtain spectra of a new target for the
circumstellar disk program (P119, Q119) which aims to observe the signatures
of circumstellar gas around main-sequence and pre-main-sequence stars.
The selected target HD 163296 is a well known active HAeBe star. It is
surrounded by a circumstellar dust and gas. Episode of accretion and outflows
have been discovered with HST.
A remnant H2 similar to the one detected with FUSE toward AB Aur
(Roberge et al. 2001) could be observed.
In any case, the comparison with AB Aur will be very fruitful.
----------------------------------------------------------------------------
Prog ID: Q221
PI: Andre, Martial
Institution: The John Hopkins University
Title: Red Rectangle Nebula
The Red Rectangle is a remarkable bipolar nebula associated with the
star HD 44179. First studied by Cohen et al (1975), the nature of this
nebula is still not well understood. High-resolution infrared imaging
Mekarnia et al (1998) showed that the nebula is produced by a compact
equatorial disk of dust. Far ultraviolet observation of this nebula may
be an enormous benefit to the study of evolving disk systems, leading
to the best source information along with previous spectroscopic
studies.
----------------------------------------------------------------------------
Prog ID: Q222
PI: Deleuil, Magali
Institution: Laboratoire Astrophysique de Marseille
Title: The H2 molecular gas in the center of M100
We propose to observe the central region of the nearby spiral galaxy M100
in order to properly measure the column density of the molecular
hydrogen gas via its absorption lines (Lyman and Werner bands). CO (J=1-0)
data are available for this galaxy as well as metallicity measurments
within the same aperture as that of FUSE.
Therefore we will be able to perform a direct measure of the CO to H2
conversion factor in a normal spiral galaxy.
----------------------------------------------------------------------------
Prog ID: Q223
PI: Ferlet, Roger
Institution: CNRS, Institut d'Astrophysique de Paris
Title: Study of Mkn36
Mkn36 is known to be a blue compact galaxy presenting a relatively
low metallicity. The purpose of this investigation is to search for
H_2 in the context of an intermediate metallicity object.
These observations should also give access to a more precise
evaluation of the elements abundances within such a galaxy as well
as the physical state of the absorbing gas.
If the stellar component responsible for the UV light is well
placed behind absorbing material presenting a small enough spread of
the velocity distribution including thermal, turbulent and large
motion broadening, then possibly an estimation of the deuterium
abundance in such a low metallicity object could be attempted.
In such a case possible follow up observationbs will have
to be considered.
----------------------------------------------------------------------------
Prog ID: Q224
PI: Lemoine, Martin
Institution: CNRS
Title: ISM in IZW36
IZW36 is known to be a blue compact galaxy presenting a relatively
low metallicity. The purpose of this investigation is to search
for H_2 in the context of an intermediate metallicity object.
These observations should also give access to a more precise
evaluation of the elements abundances within such a galaxy as
well as the physical state of the absorbing gas.
If the stellar component responsible for the UV light is well
placed behind absorbing material presenting a small enough spread of
the velocity distribution including thermal, turbulent and large
motion broadening, then possibly an estimation of the deuterium
abundance in such a low metallicity object could be attempted.
In such a case possible follow up observationbs will have
to be considered.
----------------------------------------------------------------------------
Prog ID: Q225
PI: Vidal-Madjar, Alfred
Institution: Institut d'Astrophysique de Paris
Title: Star formation in the atypical S0 galaxy NGC 5102?
NGC 5102 is a very atypical giant lenticular galaxy: (1) its ultraviolet
emission is much stronger than in other early-type galaxies observed by
the IUE satellite; (2) it is a gas-rich galaxy where HII regions have been
detected; (3) individual observations of blue stars near the center of the
galaxy with the FOC/HST suggest they are young massive stars (Deharveng et
al. 1997). All these results are evidences of a recent star-forming event.
As shown by HUT observations of other early-type galaxies (Brown et al. 1995),
NGC 5102 should also have a population of hot old stars (post-AGB, hot
horizontal branch, AGB manque stars) contributing to the ultraviolet emission.
Between 900 and 1200 A, the spectrum is very sensitive to the temperature of
the hottest stars: FUSE data should therefore be especially efficient to
disentangle the young hot stellar populations from older ones.
To this purpose, the spectral energy distribution will also be connected to
IUE data and optical and near-infrared colors.
The global spectrum (continuum and stellar lines) will finally be analyzed
with our evolutionary synthesis model PEGASE (Fioc & Rocca-Volmerange 1997,
2000) in terms of star formation history and metallicity.
Modeling the spectral energy distribution of NGC 5102 is essential to
understand both the star-forming process in ellipticals and S0's and to
analyze observations of such galaxies at high redshift, when they underwent
star formation. This will put important constraints on cosmological models of
galaxy formation.
----------------------------------------------------------------------------
Prog ID: Q301
Title: Extra-solar Planet Aurorae
PI: Vidal-Madjar
Institution: Institut d'Astrophysique de Paris
We will search for extra-solar planet aurorae emission (HI, H2) in the spectrum
of stars with known extra-solar planets. The selected targets harbor "hot
Jupiter" type planets or/and multiple systems. The observations will be
performed during the quadrature to optimize the chance of detection
using the velocity Doppler shift of the planets.
----------------------------------------------------------------------------
Prog ID: Q302
Title: Quasi Periodic Oscillations in the accretion disk of Black holes.
PI: Andre
Institution: Institut d'Astrophysique de Paris
Quasi Periodic Oscillations (QPOs) in the X-ray brightness of neutron star and
black hole X-ray binaries provide a useful probe into the inner accretion flows.
Since the discovery in 1985 (Van der Klis) numerous neutron star QPOs have been
observed with properties that depend on the spectral type of the sources (high
or low luminosity). In current nomenclature, we distinguish 8 types of neutron
star QPOs (from kHz to Hz and below). As to the black hole QPOs, a few cases
have been observed in the same frequency range and show many similarities with
neutron star QPOs. Nevertheless, at present the BH QPO studies are based on very
few objects (Dimitrios 1999). Many theoretical models have been proposed for the
different QPOs. Some of them identify the frequency with Keplerian orbital
motion others suggest a hydrodynamic pulsation in the disk, others again imply
general relativistic effects. But some of these models only apply to neutron
star QPOs (hard surface, magnetic field) and some others only to BH QPOs.
Opening the FUV window, FUSE will allow for the study of highly ionised species
in the accretion disk. In particular, the O VI doublet ratio will help to put
a limit on the density of these disk and the broadening of these lines should
also put a constraint on the Keplerian model. Since BH QPO are found to be
consistently lower than the neutron star QPOs, we suggest also the possiblity
of time resolved spectroscopy (~.1 hz) in TTAG mode. The objects we propose to
observe have been selected on a wide variety of criteria : weak stellar
continuum, low distance and low frequency QPO.
----------------------------------------------------------------------------
Prog ID: Q303
Title: P cygni line variability in WR 140
PI: Gry
Institution: Laboratoire d'Astrophysique de Marseille and ISO Data Center
WR140 is going through periastron passage of its 7.94-year eccentric
orbit in February 2001. X-ray monitoring with RXTE has shown that the
heavy X-ray absorption expected as the Wolf-Rayet star moves into the
line-of-sight to the O-star primary has started.
Previous IUE observations have shown considerable
extra absorption in P Cygni profiles was seen even months later. Nearer
periastron these absorbtion effects should be much more pronounced.
Although the interstellar absorbtion is quite high to WR140, the region
longward of 1100 A has several lines of interest that should show heavy
absorption through the WR wind. The object will be observed once during
the periastron passage and once several months later to evidence the
variations.
----------------------------------------------------------------------------
Prog ID: Q304
Title: The rapidly evolving planetary nebula Hen 3-1357
PI: Gry
Institution: Laboratoire d'Astrophysique de Marseille and ISO Data Center
Hen 3-1357 (known as the 'Stingray Nebula') is the youngest Planetary Nebula
known in the sky. It has become ionized within the past few decades and its
central star seems to be still rapidly evolving in the H-R diagram towards
hotter effective temperatures. With this proposal we want to determine the
current effective temperature of the central star and the characteristics
of the stellar wind thirteen years after its discovery with IUE.
This will enable us to determine whether the rapid spectral
changes observed in the last few years are the consequence of an
episodic post-AGB mass loss event or the result of a continuous
evolution in the H-R digram. In any of these cases, the observations will
help us to understand this short and, thus, still poorly known transition
phase which leads to the formation of a new PN.
----------------------------------------------------------------------------
Prog ID: Q305
Title: Lyman continuum radiation from galaxies
PI: Deharveng
Institution: Laboratoire d'Astronomie Spatiale
There is an on-going effort to measure the Lyman continuum radiation
escaping from galaxies. Current data suggest a cosmic evolution of
the escape fraction with implications on the contribution of star
formation to the ionisation of the intergalactic medium. Measurements
of nearby galaxies with FUSE should confirm the trend observed.
----------------------------------------------------------------------------
Prog ID: Q306
Title: Search for H2 in young circumstellar disks
PI: Lecavelier
Institution: Institut d'Astrophysique de Paris
We will search for H2 absorption lines in the spectrum of stars surrounding
by circumstellar disks in which H2 is already detected through quadrupole
rotational transitions.
By observing different inclination of disks, these observations will constrain
the spatial distribution of the molecular gas. This should help to solve the
issues raised by the observations of H2 in the Beta Pictoris disk.
----------------------------------------------------------------------------
Prog ID: Q319
Title: Circumstellar disks
PI: Deleuil
Institution: Laboratoire d'Astronomie Spatiale
The purpose of this program is to obtain spectra of new targets for the
circumstellar disk program (P119, Q119, P219, Q219) which aims to observe
the signatures of circumstellar gas around main-sequence and pre-main-sequence
stars. HD 141569 is a well-known pre-main sequence stars surrounded by a
circumstellar disk for which images have been obtained, given information
on the dust distribution and inclination of the disk.
HD 36112 is a young pre-main sequence star surrounding by a huge amount of CO.
The derivation of the CO/H2 ration will give important information on the
gaseous content as well as on the origin and history of disk around stars more
massive than the Sun.
