INTEGRAL and Swift observations of EXO 2030+375 during a giant outburst
Abstract
Aims:We investigate the X-ray spectral and timing properties of the high mass X-ray binary
Methods: The data analyzed in this work are from partly simultaneous observations with INTEGRAL and Swift. The pulse period P and its temporal derivative dot P are measured. X-ray pulse profiles in different energy ranges and time intervals are constructed. Pulse averaged X-ray spectra for different time intervals are studied.
Results: We report a strong spin-up of the source during the outburst, comparable to that observed in 1985 during the previous giant outburst when the source was discovered. The value of dot P is found to be linearly related to the X-ray luminosity of the source during the outburst. For the first time the hard X-ray (>25 keV) characteristics of the source during a type II outburst are studied. The X-ray pulse profiles apparently change with luminosity. The X-ray spectral continuum in the 3-120 keV energy range is modeled with an absorbed power law with an exponential cutoff around E∼26 keV. An iron emission line at 6-7 keV is observed. The spectrum reveals some features between 10 and 20 keV which can be modeled either by a broad emission line at 13-15 keV (a "bump") or by two absorption lines at 10 and 20 keV.
- Publication:
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Astronomy and Astrophysics
- Pub Date:
- March 2007
- DOI:
- 10.1051/0004-6361:20066801
- arXiv:
- arXiv:astro-ph/0701791
- Bibcode:
- 2007A&A...464L..45K
- Keywords:
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- X-ray binaries;
- stars: neutron;
- accretion;
- accretion disks;
- Astrophysics
- E-Print:
- 5 pages, 5 figures, accepted for publication in A&