X-ray and optical properties of new Gamma Cas-like objects discovered in X-ray surveys
| dc.creator | Motch, Christian | |
| dc.creator | de Oliveira, Raimundo Lopes | |
| dc.creator | Negueruela, Ignacio | |
| dc.creator | Haberl, Frank | |
| dc.creator | Janot-Pacheco, Eduardo | |
| dc.date | 2005-12-22 | |
| dc.date.accessioned | 2026-07-07T06:49:12Z | |
| dc.date.available | 2026-07-07T06:49:12Z | |
| dc.description | A growing number of early Be stars discovered in X-ray surveys exhibit X-ray luminosities intermediate between those of normal stars and those of most Be/X-ray binaries in quiescence. Their X-ray spectra are also much harder than those of shocked wind OB stars and can be best fitted by a thin thermal plasma with T ~ 10^8 K, added to a cooler and much fainter thermal component. An iron line complex including a fluorescence component is detected in many cases. There is no evidence for coherent pulsations in any of these systems but strong variability on time scales as short as 100 s is usually observed. Large oscillations with quasi-periods of the order of one hour or more are detected in the X-ray light curves of several sources, but have so far failed to prove to be strictly periodic. The optical and X-ray properties of these new objects strikingly resemble those of the so far unique and enigmatic Be star Gamma-Cas and define a new class of X-ray emitters. We discuss the possible origin of the X-ray emission in the light of the models proposed for Gamma-Cas, magnetic disc-star interaction or accretion onto a compact companion object -- neutron star or white dwarf. | |
| dc.description | 7 pages, to appear in "Active OB Stars: Laboratories for Stellar & Circumstellar Physics", eds. S. Stefl, S. P. Owocki & A. Okazaki. ASP Conf. Ser. 2006, in press (uses asp style) | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0512556 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0512556 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/104254 | |
| dc.subject | Astrophysics | |
| dc.title | X-ray and optical properties of new Gamma Cas-like objects discovered in X-ray surveys | |
| dc.type | text |