A low luminosity state in the massive X-ray binary SAX J0635+0533

Abstract

The X-ray pulsar SAX J0635+0533 was repeatedly observed with the XMM-Newton satellite in 2003-2004. The precise localization provided by these observations confirms the association of SAX J0635+0533 with a Be star. The source was found, for the first time, in a low intensity state, a factor ~30 lower than that seen in all previous observations. The spectrum, well fitted by an absorbed power law with photon index ~1.7 and N_H = 1.2x10^22 cm^-2, was compatible with that of the high state. The low flux did not allow the detection of the pulsations at 33.8 ms seen BeppoSAX and RXTE data. In view of the small luminosity observed in 2003-2004, we reconsider the peculiarities of this source in both the accretion and rotation powered scenarios.

Accepted for publication on Astronomy and Astrophysics

References in corpus (7)

• The European Photon Imaging Camera on XMM-Newton: The MOS Cameras
• The Second-Generation Guide Star Catalog: Description and Properties
• The XMM-Newton Serendipitous Survey. V. The Second XMM-Newton Serendipitous Source Catalogue
• XMM-Newton observations of PSr B1259-63 near the 2004 periastron passage
• Discovery of a Hard X-Ray Source, SAX J0635+0533, in the Error Box of the Gamma-Ray Source 2EG 0635+0521
• Detection of 33.8 ms X-ray pulsations in SAX J0635+0533
• XMM-Newton Observations of PSR B1957+20

Cited by in corpus (4)

• Catalog of the Galactic population of X-ray pulsars in High-mass X-ray binary systems
• Swift monitoring of the massive X-ray binary SAX J0635.2+0533
• Further evidence for natal kick segregation by spectral type in high-mass X-ray binaries
• On the origin of super-global spin-up trends of X-ray pulsars in HMXB systems