Please use this identifier to cite or link to this item:
Title: Timing and spectral studies of the transient x-ray pulsar GX 304-1 during an outburst
Authors: Devasia, Jincy
James, Marykutty
Paul, Biswajit
Indulekha, Kavila
Keywords: binaries: general
pulsars: individual
GX 304-1
X-rays binaries
X-rays: individual: GX 304-1
X-rays: stars
X-rays: stars
Issue Date: Oct-2011
Publisher: Wiley Interscience for the RAS
Citation: Monthly Notices of the Royal Astronomical Society, 2011, Vol.417, p348
Abstract: We present the timing and spectral properties of the transient X-ray pulsarGX304−1 during its recent outburst in 2010 August, using observations carried out with the Proportional Counter Array (PCA) instrument on board the Rossi X-ray Timing Explorer (RXTE) satellite. We detected strong intensity- and energy-dependent variations in the pulse profiles during the outburst. The pulse profile showed significant evolution over the outburst. It showed complex structures consisting of a main peak with steps on both sides during the start of the outburst.On some days, a sharp dip-like feature was seen which disappeared at the end of the outburst when the profile evolved into a sinusoidal shape. At low energies, the pulse profiles appeared complex, consisting of multiple peaks and a narrow minimum. The amplitude of the second brightest peak in low energies decreased with energy, and above 12 keV the shape of the pulse profile changed to a single broad peak with a dip-like feature. The dip had energy dependence, both in phase and in width. We detected quasi-periodic oscillations (QPOs) at 0.125 Hz with a harmonic. The QPO feature had a low rms value of 2.9 per cent and it showed a positive energy dependence up to 40 keV with the rms value increasing to 9 per cent at 40 keV. The QPO frequency decreased from 0.128 to 0.108 Hz in 12 days. During most of the outburst, the 3–30 keV spectrum of GX 304−1 can be well fitted with a partial covering power-law model with a high-energy cut-off and iron fluorescent line emission. For a few of the observations carried out during the decay of the outburst, the partial covering absorption component is found to change to single-component absorption. We also found that the partial covering and high-energy cut-off parameters vary significantly with the pulse phase.
Description: Restricted Access. An open-access version is available at (one of the alternative locations)
ISSN: 0035-8711
1365-2966 (Online)
Alternative Location:
Copyright: 2011 The authors & the Royal Astronomical Society.
Appears in Collections:Research Papers (A&A)

Files in This Item:
File Description SizeFormat 
  Restricted Access
Restricted access2.84 MBAdobe PDFView/Open Request a copy

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