BeppoSAX broad-band observations of Gamma Cassiopeiae

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dc.creatorOwens, A.
dc.creatorOosterbroek, T.
dc.creatorParmar, A. N.
dc.creatorSchulz, R.
dc.creatorStuwe, J. A.
dc.creatorHaberl, F.
dc.date1999-05-19
dc.date.accessioned2026-07-07T02:31:39Z
dc.date.available2026-07-07T02:31:39Z
dc.descriptionWe report broad-band X-ray measurements of the Be star Gamma Cassiopeiae by the BeppoSAX X-ray astronomy satellite. The observations took place on 1998 July, 18-23. The 0.1-200 keV X-ray spectrum is reasonably well fit by an optically thin thermal plasma model of temperature 12.5 +/- 0.6 keV with significant residuals around 0.3 keV and 1 keV. The former is interpreted as the variable soft component reported by ROSAT, although there is no evidence for variability at the 5 % level. For a blackbody interpretation, the fitted temperature is 100 +320 -13 eV, in agreement with the ROSAT value of 200 +/- 10 eV. However, a MEKAL interpretation gives a significantly lower temperature of (48 +/- 11 eV). The fitted abundances are about half solar values, in agreement with previous measurements. At higher energies, the spectrum does not require non-thermal components and the observation of a line at 6.8 keV supports the ASCA interpretation of the source as an accreting white dwarf. Assuming a source distance of 188 pc, the bolometric luminosity in the 2-10 keV band is 6 10^32 erg/s. Simultaneous optical measurements by the Wendelstein Observatory near Munich, indicate that the source continues to be in a late but rather normal Be phase, with no obvious signs of a transition to the Be-shell phase. The measured magnitudes at B, V and R wavelengths of 2.18 +/- 0.06, 2.23 +/- 0.02 and 2.36 + /- 0.03, respectively, confirm this.
dc.description5 pages. Accepted for publication in A&A
dc.identifierhttps://arxiv.org/abs/astro-ph/9905245
dc.identifierhttp://arxiv.org/abs/astro-ph/9905245
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/14232
dc.subjectAstrophysics
dc.titleBeppoSAX broad-band observations of Gamma Cassiopeiae
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