Broad band X-ray spectrum of KS 1947+300 with BeppoSAX

Abstract

We present results obtained from three BeppoSAX observations of the accretion-powered transient X-ray pulsar KS 1947+300 carried out during the declining phase of its 2000 November -- 2001 June outburst. A detailed spectral study of KS 1947+300 across a wide X-ray band (0.1--100.0 keV) is attempted for the first time here. Timing analysis of the data clearly shows a 18.7 s pulsation in the X-ray light curves in the above energy band. The pulse profile of KS 1947+300 is characterized by a broad peak with sharp rise followed by a narrow dip. The dip in the pulse profile shows a very strong energy dependence. Broad-band pulse-phase-averaged spectroscopy obtained with three of the BeppoSAX instruments shows that the energy spectrum in the 0.1--100 keV energy band has three components, a Comptonized component, a ~0.6 keV blackbody component, and a narrow and weak iron emission line at 6.7 keV with a low column density of material in the line of sight. We place an upper limit on the equivalent width of the iron K_αline at 6.4 keV of ~13 eV (for a width of 100 eV). Assuming a spherical blackbody emitting region and the distance of the source to be 10 kpc, the radius of the emitting region is found to be in the range of 14--22 km, which rules out the inner accretion disk as the soft X-ray emitting region.

17 pages, 5 figures, Accepted for publication in The Astrophysical Journal

References in corpus (8)

• Origin of the Soft Excess in X-ray Pulsars
• A Frequency Glitch in an Accreting Pulsar
• Timing and spectral studies of LMC X-4 in high and low states with Beppo-SAX: Detection of pulsations in the soft spectral component
• X-ray properties of the transient pulsar 3A 0535+262 in quiescence
• Observations of the Transient X-ray Pulsar KS 1947+300 by the INTEGRAL and RXTE Observatories
• BeppoSAX observations of the accretion-powered X-ray pulsar SMC X-1
• Detection of hard X-ray pulsations and a strong iron K_beta emission line during an extended low state of GX 1+4
• Timing and spectral studies of the transient X-ray pulsar EXO 053109-6609.2 with ASCA and Beppo-SAX

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• Rapid spectral and timing variability of Be/X-ray binaries during type II outbursts
• Timing and broad band spectroscopy of 1A 1118-61 with Suzaku
• Suzaku observations of the 2013 outburst of KS 1947+300
• Broad-band spectroscopy of the transient X-ray binary pulsar KS 1947+300 during 2013 giant outburst: Detection of pulsating soft X-ray excess component