X-ray emission from Be star/X-ray binaries

Apparao, K. M. V.

doi:10.1007/bf02101698

Cited by 28 publications

(30 citation statements)

References 170 publications

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“…(2000) and Yokogawa et al (2003). Haberl & Pietsch 1999), "giant" outbursts (factor 100-1000) are rare and are thought to be explained by increased mass outflow through the Be stellar wind disc (Apparao 1994). No giant outbursts were so far detected from any of the eleven systems.…”

Section: Long Term Variabilitymentioning

confidence: 97%

X-ray observations of Be/X-ray binaries in the SMC

Haberl

Pietsch

2004

A&A

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Abstract. Fifteen Be/X-ray binaries and candidates in the SMC were observed serendipitously with the EPIC instruments of XMM-Newton during two observations of SNR 0047-73.5 and SNR 0103-72.6 in October 2000. A total of twelve of those sources are detected. For eleven of them an accurate position and in part detection of X-ray pulsations support the proposed identification as Be/X-ray binaries. In one case the improved X-ray position excludes the previously suggested identification with an Hα emission line star found within the ROSAT error circle. The detection of pulsations (172.2 s, 320.1 s and 751 s) from three hard X-ray sources with periods known from ASCA observations confirm their proposed identifications with ROSAT sources and their optical Be star counterparts. In addition, pulsations with a period of 263.6 s were found from XMMU J004723.7−731226 = RX J0047.3−7312. For SAX J0103.2−7209 a pulse period of 341.2 ± 0.5 s was determined, continuing the large spin-up seen with ASCA, BeppoSAX and Chandra between 1996 and 1999 with a period derivative of −1.6 s yr −1 covering now 4.5 years. The 0.3-10.0 keV EPIC spectra of all eleven Be/X-ray binaries and candidates are consistent with power-law energy distributions with derived photon indices strongly peaked at 1.00 with a standard deviation of 0.16. No pulsations are detected from RX J0049.2−7311 and RX J0049.5−7310 (both near the 9 s pulsar AX J0049−732) and RX J0105.1−7211 (near AX J0105−722, which may pulsate with 3.3 s), leaving the identification of the ASCA sources with ROSAT and corresponding XMM-Newton objects still unclear. We present an updated list of high-mass X-ray binaries (HMXBs) and candidates in the SMC incorporating improved X-ray positions obtained from Chandra and XMM-Newton observations. Including the results from this work and recent publications the SMC HMXB catalogue comprises 65 objects with at least 37 showing X-ray pulsations.

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Section: Long Term Variabilitymentioning

confidence: 97%

X-ray observations of Be/X-ray binaries in the SMC

Haberl

Pietsch

2004

A&A

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“…The majority of the known accretion-powered pulsars are transients in binary systems with Be (or Oe) stars (Apparao 1994;Coe 2000). Be stars are main-sequence B stars showing emission in the Balmer lines ( Porter & Rivinius 2003;Slettebak 1988).…”

Section: Be/ X-ray Binariesmentioning

confidence: 99%

Discovery of a Be/X‐Ray Binary Consistent with the Position of GRO J2058+42

Wilson

Weisskopf

Finger

et al. 2005

ApJ

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GRO J2058+42 is a 195 s transient X-ray pulsar discovered in 1995 with BATSE. In 1996, RXTE located GRO J2058+42 to a 90% confidence error circle with a 4 0 radius. On 2004 February 20, the region including the error circle was observed with Chandra ACIS-I. No X-ray sources were detected within the error circle; however, two faint sources were detected in the ACIS-I field of view. We obtained optical observations of the brightest object, CXOU J205847.5+414637, which had about 64 X-ray counts and was just 0A3 outside the error circle. The optical spectrum contains a strong H line and corresponds to an infrared object in the Two Micron All Sky Survey catalog, indicating a Be/X-ray binary system. Pulsations were not detected in the Chandra observations, but similar flux variations and distance estimates suggest that CXOU J205847.5+414637 and GRO J2058+42 are the same object. We present results from the Chandra observation, optical observations, new and previously unreported RXTE observations, and a reanalysis of a ROSAT observation.

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“…If it is a neutron star or a black hole, a comparison with other X-ray emitting Be star binaries with early spectral type and comparable periastron distances (cf. Be star binaries with neutron stars A0538-66, A0535+26; see Apparao 1994) shows that the low energy X-ray emission is far too small. The object does not show the characteristic small time variability of black holes.…”

Section: Fig 1 the Hard X-ray Spectrum Of Lsi +61mentioning

confidence: 99%