Timing and broad-band spectroscopy of 1A 1118−61 with Suzaku

Maitra, Chandreyee; Paul, Biswajit; Naik, S.

Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/4833

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DC Field	Value	Language
dc.contributor.author	Maitra, Chandreyee	-
dc.contributor.author	Paul, Biswajit	-
dc.contributor.author	Naik, S.	-
dc.date.accessioned	2012-07-10T11:47:05Z	-
dc.date.available	2012-07-10T11:47:05Z	-
dc.date.issued	2012-03	-
dc.identifier.citation	Monthly Notices of the Royal Astronomical Society, 2012, Vol. 420, p2307-2317	en
dc.identifier.issn	0035-8711	-
dc.identifier.uri	http://hdl.handle.net/2289/4833	-
dc.description	Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)	en
dc.description.abstract	We present a timing and broad-band pulse-phase-resolved spectral analysis of the transient Be X-ray binary pulsar 1A 1118-61 observed during its outburst in 2009 January using Suzaku observations. The Suzaku observations were made twice, once at the peak of the outburst, and the other 13 d later at its declining phase. Pulse profiles from both observations exhibit strong energy dependence with several peaks at low energies and a single peak above ˜10 keV. A weak, narrow peak is detected at the main dip of the pulse profiles from both observations in the energy bands below 3 keV, indicating the presence of a phase-dependent soft excess in the source continuum. The broad-band energy spectrum of the pulsar could be fitted well with a partial covering cut-off power-law model and a narrow iron fluorescence line. We also detect a broad cyclotron feature at ˜50 keV from both observations which is a feature common for accretion-powered pulsars with high magnetic field strength. The pulse-phase-resolved spectral analysis shows an increase in the absorption column density of the partial covering component, as well as variation in the covering fraction at the dips of the pulse profiles, which naturally explains energy dependence of the same. The cyclotron line parameters also show significant variation with pulse phase with an ˜10 keV variation in the cyclotron line energy and a variation in depth by a factor of 3. This can be explained either as the effect of different viewing angles of the dipole field at different pulse phases, or due to a more complex underlying magnetic field geometry.	en
dc.language.iso	en	en
dc.publisher	Blackwell Publishing for the Royal Astronomical Society	en
dc.relation.uri	http://adsabs.harvard.edu/abs/2012MNRAS.420.2307M	en
dc.relation.uri	http://arxiv.org/abs/1111.3299	en
dc.relation.uri	http://dx.doi.org/10.1111/j.1365-2966.2011.20196.x	en
dc.rights	2012 Blackwell Publishing for the Royal Astronomical Society	en
dc.subject	Pulsars	en
dc.subject	X-ray binaries	en
dc.title	Timing and broad-band spectroscopy of 1A 1118−61 with Suzaku	en
dc.type	Article	en
Appears in Collections:	Research Papers (A&A)

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