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Discovery of the X-ray transient SAX J1808.4-3658, a likely low mass X-ray binary

J. J. M. in 't Zand·J. Heise·J. M. Muller·A. Bazzano·M. Cocchi·L. Natalucci·P. Ubertini
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Abstract

We report the discovery of a fairly bright transient during observations with the Wide Field Cameras on board the BeppoSAX satellite in September 1996. It was detected at a peak intensity of 0.1 Crab (2 to 10 keV) and lasted between 6 and 40 days above a detection threshold of 2 mCrab. Two very bright type I X-ray bursts were detected from this transient in the same observations. These almost certainly identify this X-ray transient as a low-mass X-ray binary with a neutron star as compact component. The double-peaked time history of both bursts at high energies suggests a peak luminosity close to the Eddington limit. Assuming this to be true implies a distance to this object of 4 kpc.

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J. J. M. in 't Zand, J. Heise, J. M. Muller, A. Bazzano, M. Cocchi, L. Natalucci, P. Ubertini. 1998-02-09. Discovery of the X-ray transient SAX J1808.4-3658, a likely low mass X-ray binary. https://arxiv.org/abs/astro-ph/9802098

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