Staring at 4U 1909+07 with Suzaku
Abstract
We present an analysis of the neutron star high mass X-ray binary (HMXB) 4U 1909+07 mainly based on Suzaku data. We extend the pulse period evolution, which behaves in a random-walk like manner, indicative of direct wind accretion. Studying the spectral properties of 4U 1909+07 between 0.5 to 90 keV we find that a power-law with an exponential cutoff can describe the data well, when additionally allowing for a blackbody or a partially covering absorber at low energies. We find no evidence for a cyclotron resonant scattering feature (CRSF), a feature seen in many other neutron star HMXBs sources. By performing pulse phase resolved spectroscopy we investigate the origin of the strong energy dependence of the pulse profile, which evolves from a broad two-peak profile at low energies to a profile with a single, narrow peak at energies above 20 keV. Our data show that it is very likely that a higher folding energy in the high energy peak is responsible for this behavior. This in turn leads to the assumption that we observe the two magnetic poles and their respective accretion columns at different phases, and that these accretion columns have slightly different physical conditions.
Additional Information
© 2012 ESO. Received 20 June 2012. Accepted 16 September 2012. Published online 18 October 2012. This work was supported by the Bundesministerium für Wirtschaft und Technologie through DLR grants 50OR0808, 50OR0905, and 50OR1113. F.F. thanks GSFC for the hospitality. This research has made use of data obtained from the Suzaku satellite, a collaborative mission between the space agencies of Japan (JAXA) and the USA (NASA). This work is furthermore based on observations with INTEGRAL, an ESA project with instruments and science data centre funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, Spain), Czech Republic and Poland, and with the participation of Russia and the USA. We have made use of NASA's Astrophysics Data System. We like to thank J. E. Davis for the slxfig module which was used to create all plots throughout this paper.Attached Files
Published - aa19845-12.pdf
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Additional details
- Eprint ID
- 36432
- Resolver ID
- CaltechAUTHORS:20130116-141359975
- Bundesministerium für Wirtschaft und Technologie (BMWi)
- 50OR0808
- Bundesministerium für Wirtschaft und Technologie (BMWi)
- 50OR0905
- Bundesministerium für Wirtschaft und Technologie (BMWi)
- 50OR1113
- ESA Member States
- Deutsches Zentrum für Luft- und Raumfahrt (DLR)
- Created
-
2013-01-16Created from EPrint's datestamp field
- Updated
-
2021-11-09Created from EPrint's last_modified field
- Caltech groups
- Space Radiation Laboratory