SwiftObservations of SAX J1808.4-3658: Monitoring the Return to Quiescence

2008/07/28 by S. Campana, Sergio Campana, L. Stella +3
Physics and Astronomy · #Astrophysical Phenomena and Observations #Gamma-ray bursts and supernovae #Pulsars and Gravitational Waves Research #astro-ph

paper · pdf · doi:10.1086/592002

Accepted for publication in ApJL. 4 pages 3 figures

arxiv created 2008/07/28 · openalex publication_date 2008/08/28 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01

Abstract

The transient accreting millisecond pulsar SAX J1808.4–3658 has shown several outbursts to date but the transition from outburst to quiescence has never been investigated in detail. Thanks to the Swift observing flexibility, we monitored for the first time the decay to quiescence during the 2005 outburst. At variance with other transients, wide luminosity variations are observed. In addition, close to quiescence, SAX J1808.4–3658 seems to switch between two different states. We interpret them in terms of the accretion states accessible to a magnetized, fast-rotating neutron star.

Citations

• The Bright Optical Companion to the Eclipsing Millisecond Pulsar in NGC 6397
• The Swift X-ray Telescope
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• Discovery of a Second Millisecond Accreting Pulsar: XTE J1751−305
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