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تسجيل مستخدم جديدDiscovery of pulsations from the Be/X-ray binary RX J0101.3-7211 in the SMC by XMM-Newton
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M. Sasaki
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We report pulsations in the X-ray flux of RX J0101.3-7211 in the Small Magellanic Cloud (SMC) with a period of 455+/-2 s in XMM-Newton EPIC-PN data. The X-ray spectrum can be described by a power-law with a photon index of 0.6+/-0.1. Timing analysis of ROSAT PSPC and HRI archival data confirms the pulsations and indicates a period increase of ~5 s since 1993. RX J0101.3-7211 varied in brightness during the ROSAT observations with timescales of years with a maximum unabsorbed flux of 6 x 10^-13 erg cm^-2 s^-1 (0.1 - 2.4 keV). The flux during the XMM-Newton observation in the ROSAT band was lower than during the faintest ROSAT detection. The unabsorbed luminosity derived from the EPIC-PN spectrum is 2 x 10^35 erg s^-1 (0.2 - 10.0 keV) assuming a distance of 60 kpc. Optical spectra of the proposed counterpart taken at the 2.3 m telescope of MSSSO in Australia in August 2000 show strong Halpha emission and indicate a Be star. The X-ray and optical data confirm RX J0101.3-7211 as a Be/X-ray binary pulsar in the SMC.
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Many X-ray accreting pulsars have a soft excess below 10 keV. This feature has been detected also in faint sources and at low luminosity levels, suggesting that it is an ubiquitous phenomenon. In the case of the high luminosity pulsars (Lx > 10^36 er
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