Broad band X-ray spectroscopy of A0535+262 with SUZAKU

Abstract

The transient X-ray binary pulsar A0535+262 was observed with Suzaku on 2005 September 14 when the source was in the declining phase of the August-September minor outburst. The ~103 s X-ray pulse profile was strongly energy dependent, a double peaked profile at soft X-ray energy band (<3 keV) and a single peaked smooth profile at hard X-rays. The width of the primary dip is found to be increasing with energy. The broad-band energy spectrum of the pulsar is well described with a Negative and Positive power-law with EXponential (NPEX) continuum model along with a blackbody component for soft excess. A weak iron K_alpha emission line with an equivalent width ~25 eV was detected in the source spectrum. The blackbody component is found to be pulsating over the pulse phase implying the accretion column and/or the inner edge of the accretion disk may be the possible emission site of the soft excess in A0535+262. The higher value of the column density is believed to be the cause of the secondary dip at the soft X-ray energy band. The iron line equivalent width is found to be constant (within errors) over the pulse phase. However, a sinusoidal type of flux variation of iron emission line, in phase with the hard X-ray flux suggests that the inner accretion disk is the possible emission region of the iron fluorescence line.

arXiv comment21 pages, 6 figures. Accepted for publication in the Astrophysical Journal, 2008 January issue

References in corpus (13)

• Observations of Accreting Pulsars
• Hard X-ray Detector (HXD) on Board Suzaku
• Magnetic Fields of Accreting X-Ray Pulsars with the Rossi X-Ray Timing Explorer
• In-Orbit Performance of the Hard X-ray Detector on board Suzaku
• Origin of the Soft Excess in X-ray Pulsars
• A 0535+26 in the August/September 2005 outburst observed by RXTE and INTEGRAL
• The distances to the X-ray binaries LSI +61 303 and A0535+262
• Nature of the Soft Spectral Component in the X-ray Pulsars SMC X-1 and LMC X-4
• Cyclotron resonance energies at a low X-ray luminosity: A0535+262 observed with Suzaku
• Timing and spectral studies of LMC X-4 in high and low states with Beppo-SAX: Detection of pulsations in the soft spectral component
• Cyclical behaviour and disc truncation in the Be/X-ray binary A0535+26
• X-ray properties of the transient pulsar 3A 0535+262 in quiescence
• BeppoSAX observations of the accretion-powered X-ray pulsar SMC X-1

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