Title:	Possible detection of a cyclotron resonance scattering feature in the X-ray pulsar 4U 1909+07.
Authors:	Jaisawal, Gaurava K. Nair, Sachindra Paul, Biswajit
Keywords:	Individual (4U 1909+07)
Issue Date:	10-Dec-2013
Publisher:	IOP Sciences for The American Astronomical Society
Citation:	Astrophysical Journal, 2013, Vol.779, p54
Abstract:	We present timing and broad band spectral studies of the high-mass X-ray binary pulsar 4U 1909+07 using data from Suzaku observations during 2010 November 2–3. The pulse period of the pulsar is estimated to be 604.11 ± 0.14 s. Pulsations are seen in the X-ray light curve up to ~70 keV. The pulse profile is found to be strongly energy-dependent: a complex, multi-peaked structure at low energy becomes a simple single peak at higher energy. We found that the 1–70 keV pulse-averaged continuum can be fit by the sum of a blackbody and a partial covering Negative and Positive power law with Exponential cutoff model. A weak iron fluorescence emission line at 6.4 keV was detected in the spectrum. An absorption-like feature at ~44 keV was clearly seen in the residuals of the spectral fitting, independent of the continuum model adopted. To check the possible presence of a cyclotron resonance scattering feature (CRSF) in the spectrum, we normalized the pulsar spectrum with the spectrum of the Crab Nebula. The resulting Crab ratio also showed a clear dip centered at ~44 keV. We performed statistical tests on the residuals of the spectral fitting and also on the Crab spectral ratio to determine the significance of the absorption-like feature and identified it as a CRSF of the pulsar. We estimated the corresponding surface magnetic field of the pulsar to be 3.8 × 1012 G.
Description:	Restricted Access
URI:	http://hdl.handle.net/2289/5929
ISSN:	0004-637X 1538-4357-(Online)
Alternative Location:	http://ads.nao.ac.jp//abs/2013ApJ...779...54J http://arxiv.org/abs/1310.0948 http://dx.doi.org/10.1088/0004-637X/779/1/54
Copyright:	2013 American Astronomical Society, This article may be downloaded for personal use only. Any other use requires prior permission of the author and The American Astronomical Society
Appears in Collections:	Research Papers (A&A)

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