AAS 199th meeting, Washington, DC, January 2002
Session 17. Pulsars, White Dwarfs and Galactic Gamma Ray Sources
Display, Monday, January 7, 2002, 9:20am-6:30pm, Exhibit Hall

[17.03] Chandra Imaging of the Black Widow Pulsar B1957+20

B.M. Gaensler (Harvard-Smithsonian CfA), B.W. Stappers (ASTRON), V.M. Kaspi (McGill U), M. van der Klis (U Amsterdam), W.H.G. Lewin (MIT )

The Black Widow pulsar'', PSR~B1957+20, is a binary millisecond pulsar whose relativistic wind is both steadily ablating its companion and is also generating an H\alpha bow-shock nebula as the pulsar ploughs through the surrounding ISM. This system thus presents the opportunity to study the wind of a weakly-magnetized pulsar, in contrast to the winds around young pulsars like the Crab.

We here report on a 43 ksec observation of PSR~B1957+20, using the ACIS-S detector on-board the {\em Chandra X-ray Observatory}. We clearly detect X-rays from this source, the morphology consisting of a compact source at the position of the pulsar and a narrow feature of length 30'' trailing back along the pulsar's direction of motion. We discuss this morphology in terms of emission from the intra-binary shock, from the ISM bow-shock and from the pulsar itself, and use these results to probe the particle spectrum of the pulsar wind in two distinct energy regimes.

This work was supported by NASA through a CXO Guest Observer grant (GO1-2033X).