Possible contributions of the Groupe d’Astrophysique des Hautes Energies (GAPHE) to the GAIA data processing

Eric Gosset, Gregor Rauw, Yaël Nazé & Hugues SanaInstitut d’Astrophysique et de Géophysique, Université de Liège

Topics addressed in this talk:

The GAPHE and its research activities related to The GAPHE and its research activities related to early-type stars early-type stars

Orbital solutions for spectroscopic binariesOrbital solutions for spectroscopic binaries GAIAGAIA support observations of early-type stars support observations of early-type stars

from the groundfrom the ground Photometric studies of Wolf-Rayet starsPhotometric studies of Wolf-Rayet stars

1. The GAPHE and its research activities related to early-type stars

Currently (February 2006) the GAPHE consists of Currently (February 2006) the GAPHE consists of 2 senior scientists, 3 post-docs and 2 PhD 2 senior scientists, 3 post-docs and 2 PhD students mainly working on high-energy datastudents mainly working on high-energy data

76 publications (50 in refereed journals) related to 76 publications (50 in refereed journals) related to early-type stars over the last five years. early-type stars over the last five years.

Many Many successful proposalssuccessful proposals on ground-based on ground-based (ESO, OHP, CTIO, VLA) and spaceborne ((ESO, OHP, CTIO, VLA) and spaceborne (XMM-XMM-Newton, Chandra, INTEGRALNewton, Chandra, INTEGRAL) facilities ) facilities

Multi-wavelength studies of many categories of early-type stars: Normal O stars: Normal O stars: e.g.e.g. CPD CPD –– 41° 7742 41° 7742 ( (O9V + B1-1.5VO9V + B1-1.5V, , Sana et al. 2003, Sana et al. 2003,

2005, X-rays + optical2005, X-rays + optical)…)…

Peculiar Of stars: Peculiar Of stars: e.g.e.g. BD +60° 2522BD +60° 2522 (Oef, (Oef, Rauw et al. 2003, opticalRauw et al. 2003, optical), ),

HD 108HD 108 (Of?p, (Of?p, Nazé et al. 2001, 2004, X-rays + opticalNazé et al. 2001, 2004, X-rays + optical),), Wolf-Rayet stars: Wolf-Rayet stars: e.g. e.g. WR 40WR 40 (WN8, Gosset et al. 2005, X-rays + optical),(WN8, Gosset et al. 2005, X-rays + optical),

WR 20aWR 20a (WN6ha + WN6ha, Rauw et al. 2004, 2005, optical)(WN6ha + WN6ha, Rauw et al. 2004, 2005, optical)

B[e] stars: B[e] stars: e.g.e.g. He 3-209He 3-209 (Nazé et al. 2006, optical)(Nazé et al. 2006, optical)

LBVs: LBVs: e.g.e.g. HD 5980HD 5980 (Nazé et al. 2002, 2003, 2004, X-rays)(Nazé et al. 2002, 2003, 2004, X-rays)

Non-thermal radio emitters: Non-thermal radio emitters: e.g.e.g. 9 Sgr9 Sgr ((O4 V + O7-8VO4 V + O7-8V, , Rauw et Rauw et

al. 2002, 2005, X-rays + radio + opticalal. 2002, 2005, X-rays + radio + optical),), Cyg OB2 #8aCyg OB2 #8a ((O6f + O5.5(f)O6f + O5.5(f), , De Becker et De Becker et

al. 2004, 2005, 2006, X-rays + gamma-rays + optical + radioal. 2004, 2005, 2006, X-rays + gamma-rays + optical + radio),), … …

Some science topics addressed by our team High-energy properties of early-type starsHigh-energy properties of early-type stars Fundamental properties of early-type stars in binaries Fundamental properties of early-type stars in binaries The colliding wind phenomenon in massive binariesThe colliding wind phenomenon in massive binaries Non-thermal phenomena in stellar windsNon-thermal phenomena in stellar winds Massive stars and their surroundings (He Massive stars and their surroundings (He IIII nebulae, nebulae,

wind-blown bubbles and star formation processes in wind-blown bubbles and star formation processes in young open clusters) young open clusters)

Intrinsic variability of (presumably) single early-type Intrinsic variability of (presumably) single early-type starsstars

High energy properties of early-type stars

XMM-NewtonXMM-Newton and and INTEGRALINTEGRAL studies of the X-ray studies of the X-ray and soft gamma-ray emission from clusters of and soft gamma-ray emission from clusters of massive stars: massive stars:

Fundamental properties of early-type stars in binaries…Massive binaries in young open clusters: Massive binaries in young open clusters: - NGC 6231, Trumpler 16 and IC 1805 : study of early-type NGC 6231, Trumpler 16 and IC 1805 : study of early-type

binaries and hierarchical triple systems, analysis of binaries and hierarchical triple systems, analysis of spectroscopic orbital solutions and photometric eclipses spectroscopic orbital solutions and photometric eclipses accurate absolute parametersaccurate absolute parameters

…and the colliding wind phenomenon

Optical and X-ray monitoring of a sample of colliding wind Optical and X-ray monitoring of a sample of colliding wind binaries in various evolutionary stages from Obinaries in various evolutionary stages from OVV to WR: to WR: optical line profile variability, X-ray flux modulations and optical line profile variability, X-ray flux modulations and hydro simulations hydro simulations constraints on the mass loss rates and constraints on the mass loss rates and physics of stellar windsphysics of stellar winds

2. Orbital solutions for spectroscopic binaries

A large fraction of the stars in our Galaxy (about A large fraction of the stars in our Galaxy (about 50% depending on the spectral type) are binary 50% depending on the spectral type) are binary systems. systems.

Depending on the orbital period and inclination, Depending on the orbital period and inclination, they may be seen as spectroscopic binaries.they may be seen as spectroscopic binaries.

The RVS instrument onboard The RVS instrument onboard GAIAGAIA will provide will provide radial velocity measurements for a huge number radial velocity measurements for a huge number of binaries of binaries need to use an need to use an efficient algorithm efficient algorithm to handle this large set of datato handle this large set of data. The method also . The method also needs to be needs to be robust, i.e. able to deal with all sorts robust, i.e. able to deal with all sorts of binary systemsof binary systems (early-type, late-type, (early-type, late-type, interacting binaries…)interacting binaries…)

Depending on the available manpower, we intend to test and implement different methods (for instance based on genetic algorithms) on a large number of real and simulated data.

Some peculiar problems with the orbital solution of early-type binaries…

Due to the expanding Due to the expanding motion of the stellar wind, motion of the stellar wind, different spectral lines that different spectral lines that are formed in the wind are formed in the wind yield different apparent yield different apparent systemic velocities systemic velocities (similar problems occur (similar problems occur for cataclysmic variables for cataclysmic variables and X-ray binaries) and X-ray binaries) foresee the possibility of foresee the possibility of different apparent different apparent systemic velocitiessystemic velocities

3. GAIA support observations of early-type stars from the ground

High-resolution spectroscopic observations of High-resolution spectroscopic observations of early-type stars of all sorts of spectral types (WN, early-type stars of all sorts of spectral types (WN, WC, Of, O,…) either over the RVS spectral WC, Of, O,…) either over the RVS spectral domain or over a broader wavelength range. domain or over a broader wavelength range.

These observations should complement the data These observations should complement the data set of Munari & Tomasella (set of Munari & Tomasella (1999, A&AS 137, 5211999, A&AS 137, 521))

We have a large set of high-resolution FEROS data at our disposal and we are conducting spectroscopic surveys at OHP (Elodie and Aurelie spectrographs) and ESO (FEROS).

4. Photometric studies of Wolf-Rayet stars

Narrow-band photometric filters allow to identify Narrow-band photometric filters allow to identify Wolf-Rayet stars (Wolf-Rayet stars (Royer et al. 2001, A&A 366, L1Royer et al. 2001, A&A 366, L1) and to ) and to discriminate between different WR-subtypes.discriminate between different WR-subtypes.

4. Photometric studies of Wolf-Rayet stars

Narrow-band photometric filters allow to identify Narrow-band photometric filters allow to identify Wolf-Rayet stars (Wolf-Rayet stars (Royer et al. 2001, A&A 366, L1Royer et al. 2001, A&A 366, L1) and to ) and to discriminate between different WR-subtypes.discriminate between different WR-subtypes.

Synthetic photometry (Synthetic photometry (see Royer et al. 1998, A&AS 130, see Royer et al. 1998, A&AS 130,

407407) can be used to evaluate the capabilities of the ) can be used to evaluate the capabilities of the GAIAGAIA photometric system in this respect. photometric system in this respect.

Our team has a large experience in photometric Our team has a large experience in photometric variability studies of WR stars (in particular for variability studies of WR stars (in particular for the interpretation of variations in the emission the interpretation of variations in the emission lines and in the continuum).lines and in the continuum).

Our team has a long-standing experience in the simulation of narrow-band photometry of Wolf-Rayet stars and in the interpretation of the photometric variability of these stars.