A High-Resolution X-Ray Spectrum of Centaurus X-3
Abstract
The high-mass X-ray binary pulsar Centaurus X-3 was observed with the Broad Band X-Ray Telescope (BBXRT) in 1990 December as part of the Astro-1 mission on the Space Shuttle Columbia. During the ∼1600 s observation, the system was in a high-luminosity postegress state. With an energy resolution of about 150 eV FWHM at 6 keV, the Fe K emission feature was resolved into at least two components. We found a broad ( ∼740 eV FWHM) emission feature at 6.7 keV which is probably a blend of lines from Fe xxi to Fe xxvi due to X-ray photoionization of the stellar wind of the companion. This is the first time the physical width of the 6.7 keV feature has been measured in Cen X-3. We also found evidence for a weak emission line at 6.4 keV with no discernible width, which we attribute to fluorescence of iron in relatively low ionization states. We did not detect pulsations in the iron emission features, but our sensitivity does not rule out the presence of pulsations with 50% amplitude as reported by Day et al. in 1993. We confirm the presence of quasi-periodic oscillations at about 40 mHz.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 1996
- DOI:
- 10.1086/176739
- Bibcode:
- 1996ApJ...457..397A
- Keywords:
-
- LINE: IDENTIFICATION;
- STARS: PULSARS: INDIVIDUAL NAME: CENTAURUS X-3;
- STARS: OSCILLATIONS;
- X-RAYS: STARS