Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/3579
Full metadata record
DC FieldValueLanguage
dc.contributor.authorKaur, Ramanpreet-
dc.contributor.authorPaul, Biswajit-
dc.contributor.authorKumar, Brijesh-
dc.contributor.authorSagar, R.-
dc.date.accessioned2008-06-28T11:06:56Z-
dc.date.available2008-06-28T11:06:56Z-
dc.date.issued2008-04-
dc.identifier.citationAstrophysical Journal, 2008, Vol.676, p1184-1188en
dc.identifier.issnP-ISSN : 0004-637X.-
dc.identifier.issnE-ISSN : 1538-4357-
dc.identifier.urihttp://hdl.handle.net/2289/3579-
dc.descriptionRestricted Access. Articles older than 2 years are open to all at the journal site (alternative location)en
dc.description.abstractWe report here a study of the long-term properties of quasiperiodic oscillations (QPOs) in an unusual accreting X-ray pulsar, 4U 1626-67. This is a unique accretion-powered X-ray pulsar in which we have found the QPOs to be present during all sufficiently long X-ray observations with a wide range of X-ray observatories. In the present spin-down era of this source, the QPO central frequency is found to be decreasing. In the earlier spin-up era of this source, there are only two reports of QPO detections, in 1983 with EXOSAT and 1988 with Ginga with an increasing trend. The QPO frequency evolution in 4U 1626-67 during the last 22 years changed from a positive to a negative trend, somewhat coincident with the torque reversal in this source. In the accretion-powered X-ray pulsars, the QPO frequency is directly related to the inner radius of the accretion disk, as per the Keplerian frequency model (KFM) and the beat frequency mdel (BFM). A gradual depletion of accretion disk is reported earlier from the X-ray spectral, flux, and pulse profile measurements. The present QPO frequency evolution study shows that X-ray flux and mass accretion rate may not change by the same factor; hence the simple KFM and BFM are not able to explain the QPO evolution in this source. This is the only X-ray pulsar to show persistent QPOs and is also the first accreting X-ray pulsar in which the QPO history is reported for a long timescale relating it with the long-term evolution of the accretion disk.en
dc.format.extent238469 bytes-
dc.format.mimetypeapplication/pdf-
dc.language.isoenen
dc.publisherUniversity of Chicago Press for the American Astronomical Societyen
dc.relation.urihttp://adsabs.harvard.edu/abs/2008ApJ...676.1184Ken
dc.relation.urihttp://arxiv.org/abs/0801.1761en
dc.relation.urihttp://dx.doi.org/10.1086/529130en
dc.rights2008: The American Astronomical Societyen
dc.subjectBinaries: Closeen
dc.subjectPulsars: Individual: Alphanumeric: 4U 1626-67en
dc.subjectStars: Neutron, X-Rays: Binariesen
dc.titleA study of the long-term evolution of quasi-periodic oscillations in the accretion-powered X-ray pulsar 4U 1626-67en
dc.typeArticleen
Appears in Collections:Research Papers (A&A)

Files in This Item:
File Description SizeFormat 
2008 APJ V676 p1184.pdf
  Restricted Access
Restricted Access232.88 kBAdobe PDFView/Open Request a copy


Items in RRI Digital Repository are protected by copyright, with all rights reserved, unless otherwise indicated.