Volume 388, Number 1, June II 2002
|Page(s)||335 - 345|
|Published online||28 May 2002|
High-resolution X-ray imaging of the colliding wind shock in WR 147
Department of Physics & Astronomy, The University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
2 Department of Physics & Astronomy, The University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
3 Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
4 Computer & Scientific Co. Ltd., 230 Graham Rd., Sheffield, S10 3GS, UK
5 CASA, UCB 389, University of Colorado, Boulder, CO 80309, USA
6 Universities Space Research Association, 7501 Forbes Blvd, Ste 206, Seabrook, MD 20706, USA
7 Laboratory for High Energy Astrophysics, Goddard Space Flight Center, Greenbelt, MD 20771, USA
8 Départment de physique, Université de Montréal, C P 6128, Succ. Centre-Ville, Montréal, QC, H3C 3J7, Canada
9 Observatoire du mont Mégantic
Corresponding author: J. M. Pittard, firstname.lastname@example.org
Accepted: 26 March 2002
We analyze new high-resolution Chandra X-ray images of the Wolf-Rayet binary system WR147. This system contains a WN8 star with an early-type companion located to its north, and is the only known early-type binary with a separation on the sky large enough for the wind-wind collision between the stars to currently be resolved at X-ray energies. The 5 ksec Chandra HRC-I image provides the first direct evidence for spatially extended X-ray emission in an early-type binary system. The X-ray emission peaks close to the position of the radio bow shock and north of the WN8 star. A deeper X-ray image is needed to accurately determine the degree of spatial extension, to exactly align the X-ray and optical/radio frames, and to determine whether part of the detected X-ray emission arises in the individual stellar winds. Simulated X-ray images of the wind-wind collision have a FWHM consistent with the data, and maximum likelihood fits suggest that a deeper observation may also constrain the inclination and wind momentum ratio of this system. However, as the WR wind dominates the colliding wind X-ray emission it appears unlikely that and can be separately determined from X-ray observations. We also note an inconsistency between numerical and analytical estimates of the X-ray luminosity ratio of the stronger and weaker wind components, and conclude that the analytical results are in error.
Key words: stars: binaries: general / stars: early-type / stars: imaging / stars: individual: WR 147 / stars: Wolf-Rayet / X-rays: stars
© ESO, 2002
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