Swift/XRT monitoring of five orbital cycles of LSI +61 303

dc.creatorEsposito, P.
dc.creatorCaraveo, P. A.
dc.creatorPellizzoni, A.
dc.creatorDe Luca, A.
dc.creatorGehrels, N.
dc.creatorMarelli, M. A.
dc.date2007-08-24
dc.date2007-10-12
dc.date.accessioned2026-07-07T12:44:28Z
dc.date.available2026-07-07T12:44:28Z
dc.descriptionLSI +61 303 is one of the most interesting high-mass X-ray binaries owing to its spatially resolved radio emission and its TeV emission, generally attributed to non-thermal particles in an accretion-powered relativistic jet or in the termination shock of the relativistic wind of a young pulsar. Also, the nature of the compact object is still debated. Only LS 5039 and PSR B1259-63 (which hosts a non-accreting millisecond pulsar) have similar characteristics. We study the X-ray emission from LSI +61 303 covering both short-term and orbital variability. We also investigate the source spectral properties in the soft X-ray (0.3-10 keV) energy range. 25 snapshot observations of LSI +61 303 have been collected in 2006 with the XRT instrument on-board the Swift satellite over a period of four months, corresponding to about five orbital cycles. Since individual data sets have too few counts for a meaningful spectral analysis, we extracted a cumulative spectrum. The count rate folded at the orbital phase shows a clear modulation pattern at the 26.5 days period and suggests that the X-ray peak occurs around phase 0.65. Moreover, the X-ray emission appears to be variable on a timescale of ~1 ks. The cumulative spectrum is well described by an absorbed power-law model, with hydrogen column density Nh=(5.7+/-0.3)E+21 cm^-2 and photon index 1.78+/-0.05. No accretion disk signatures, such as an iron line, are found in the spectrum.
dc.descriptionRevised to match the A&A version
dc.identifierhttps://arxiv.org/abs/0708.3330
dc.identifierhttp://arxiv.org/abs/0708.3330
dc.identifierAstronomy and Astrophysics, Volume 474, Issue 2, November I 2007, pp.575-578
dc.identifierdoi:10.1051/0004-6361:20078334
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/220782
dc.subjectAstrophysics
dc.titleSwift/XRT monitoring of five orbital cycles of LSI +61 303
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