19/02/09ARC Meeting, Colonster The Simbol-X mission and the investigation of hard X-rays from massive stars Michaël De Becker (Groupe d'AstroPhysique des Hautes Energies)

19/02/09ARC Meeting, Colonster Outline Simbol-X in a few words... - Mission concept - Science programme Potential Belgian scientific participation Concluding remarks

19/02/09ARC Meeting, Colonster Simbol-X: mission concept Main partners: CNES (France), ASI (Italy) + participation of Germany + ??? Formation flight concept: mirror module + detector module Focal length ~ 20 m Mirrors: 100 shells (grazing incidence telescope) Detectors: 2 layers (low energy and high energy) Ang. Res. < keV Energy range: 0.5 – 80 keV Unprecedented sensitivity in this energy range

19/02/09ARC Meeting, Colonster Simbol-X: mission concept Main partners: CNES (France), ASI (Italy) + participation of Germany + ??? Formation flight concept: mirror module + detector module Focal length ~ 20 m Mirrors: 100 shells (grazing incidence telescope) Detectors: 2 layers (low energy and high energy) Ang. Res. < keV Energy range: 0.5 – 80 keV Unprecedented sensitivity in this energy range IXO/HXT goal

19/02/09ARC Meeting, Colonster Simbol-X: mission concept Operational considerations Orbit: - eccentric, with perigee at km and apogee at km - four days, with data transfer to ground segment once per orbit Operation policy: observatory mission, with call for proposals and about 30% of GT Mission duration: 3 years + provision for 2 years

19/02/09ARC Meeting, Colonster Simbol-X: science programme Black holes physics resolve 50% of the cosmic X-ray background peaking at keV investigate Sgr A* and its environment constrain the physics of accretion flows, onto degenerate stars and central galactic black holes Particle acceleration mechanisms in relativistic jets of blazars in the strong field of pulsars in supernova remnants in clusters of galaxies

19/02/09ARC Meeting, Colonster Potential participation Current status of the mission: Simbol-X will enter Phase B this year Initially: bilateral partnership between CNES and ASI But: after the substantial decrease of the Italian participation, CNES is searching for additional partners : Spain, Switzerland, Polland.... Belgium? A CNES delegation came to Liège recently in order to present the status of the mission, and to discuss potential Belgian contributions Potential contributions have been identified both from the technical (CSL) and scientific (GAPHE) point of view....

19/02/09ARC Meeting, Colonster Potential participation: science In the radio domain… Stellar winds produce a thermal emission (free-free emission). In some cases, synchrotron radiation has been identified (White 1985)  presence of a population of relativistic electrons  acceleration process at work Relativistic electrons are present  non-thermal emission processes may be considered in the high-energy domain as well Massive stars are strong UV and visible emitters  Inverse Compton scattering is expected to be efficient  non-thermal X-ray emission expected : power law !! Particle acceleration in colliding-wind massive binaries:

19/02/09ARC Meeting, Colonster Potential participation: science Particle acceleration in colliding-wind massive binaries: In X-rays… Stellar winds collide with pre-shock velocities of km/s  hydrodynamic shocks  high post-shock temperatures  strong THERMAL X-ray emission The soft X-ray spectrum is dominated by the thermal emission  any putative non-thermal emission component will be overwhelmed by the thermal spectrum  strong need to investigate the hard X-ray domain

19/02/09ARC Meeting, Colonster Potential participation: science Simbol-X

19/02/09ARC Meeting, Colonster Potential participation: science Catalogues of non-thermal radio emitters O-type: 16 systems ex: Cyg OB2 #8A (O + O) WR-type: 18 systems ex: WR140 (WR + O) (see De Becker 2007, A&ARv, 14, 171 for a census of NT emitting massive stars) + example of Eta Car: first detection of hard X-rays from a massive star system

19/02/09ARC Meeting, Colonster Potential participation: science Cyg OB2 #8a: O6I + O5.5III, P ~22 d, e ~ 0.24 Simbol-X simulation. The flux of the power law was arbitrarily set to one tenth of the upper limit derived from INTEGRAL-ISGRI observations (see De Becker et al. 2007, A&A, 472, 905)

19/02/09ARC Meeting, Colonster Potential participation: science The issue of the non-thermal emission from colliding-wind binaries is a relevant science case for Simbol-X, in agreement with the main scientific themes of the mission Simbol-X observations, in the context of a broader multiwavelength campaign already well-advanced, are expected to provide crucial information for the understanding of the physics of particle acceleration in colliding-wind massive binaries : hard X-ray flux, spectral index, variation as a function of the orbital phase… Relevant targets are already identified

19/02/09ARC Meeting, Colonster Concluding remarks Simbol-X constitutes a very interesting mission with unprecedented imaging and spectral capabilities in the hard X-ray domain A potential Belgian participation is envisaged A technical contribution to the payload, or to the characterization of the mirrors, is not excluded (CSL...) A relevant scientific contribution has also been identified (GAPHE...)