Variable Quasi Periodic Oscillations during an Outburst of the Transient X-ray Pulsar XTE J1858 + 034

Mukherjee, U and Bapna, S and Raichur, H and Paul, B and Jaaffrey, SNA (2006) Variable Quasi Periodic Oscillations during an Outburst of the Transient X-ray Pulsar XTE J1858 + 034. In: Journal Of Astrophysics And Astronomy, 27 (1). pp. 25-35.

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Abstract

We have investigated the Quasi Periodic Oscillation (QPO) properties of the transient accreting X-ray pulsar XTE J 1858 + 034 during the second outburst of this source in April-May 2004. We have used observations made with the Proportional Counter Array (PCA) of the Rossi X-ray Timing Explorer (RXTE) during May 14-18, 2004, in the declining phase of the outburst. We detected the presence of low frequency QPOs in the frequency range of 140-185 mHz in all the RXTE-PCA observations. We report evolution of the QPO parameters with the time, X-ray flux, and X-ray photon energy. Though a correlation between the QPO centroid frequency and the instantaneous X-ray flux is not very clear from the data, we point Out that the QPO frequency and the one day averaged X-ray flux decreased with time during these observations. We have obtained a clear energy dependence of the RMS variation in the QPOs, increasing from about 3% at 3 keV to 6% at 25 keV. The X-ray pulse profile is a single peaked sinusoidal, with pulse fraction increasing from 20% at 3 keV to 45% at 30 keV. We found that, similar to the previous outburst, the energy spectrum is well fitted with a model consisting of a cut-off power law along with an iron emission line.

Item Type:	Journal Article
Publication:	Journal Of Astrophysics And Astronomy
Publisher:	Indian Academy Sciences
Additional Information:	Copyright of this article belongs to Indian Academy Sciences.
Keywords:	Stars;pulsar;individual (XTE J1858 + 034) - X-rays;pulsar.
Department/Centre:	Division of Physical & Mathematical Sciences > Joint Astronomy Programme
Date Deposited:	13 Apr 2009 08:52
Last Modified:	19 Sep 2010 04:58
URI:	http://eprints.iisc.ac.in/id/eprint/17886

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