- Simultaneous INTEGRAL and RXTE observations of the accreting millisecond pulsar HETE J1900.1-2455
- Astronomy & Astrophysics
- Pages (from-to)
- Document type
- Faculty of Science (FNWI)
- Anton Pannekoek Institute for Astronomy (API)
Aims.HETE J1900.1-2455 is the seventh known X-ray transient accreting millisecond pulsar and has been in outburst for more than one year. We compared the data on HETE J1900.1-2455 with other similar objects and made an attempt at deriving constraints on the physical processes responsible for a spectral formation. Methods: The broad-band spectrum of the persistent emission in the 2-300 keV energy band and the timing properties were studied using simultaneous INTEGRAL and publicly available RXTE data obtained in October 2005. The properties of the X-ray bursts observed from HETE J1900.1-2455 were also investigated. Results: The spectrum is well described by a two-component model consisting of a blackbody-like soft X-ray emission at 0.8 keV temperature and a thermal Comptonized spectrum with electron temperature of 30 keV and Thomson optical depth tauT Ëœ 2 for the slab geometry. The source is detected by INTEGRAL up to 200 keV at a luminosity of 5×1036 erg s-1 (assuming a distance of 5 kpc) in the 0.1-200 keV energy band. We have also detected one type I X-ray burst which shows photospheric radius expansion. The burst occurred at an inferred persistent emission level of ~3-4% of the Eddington luminosity. Using data for all X-ray bursts observed to date from HETE J1900.1-2455, the burst recurrence time is estimated to be about 2 days. No pulsations have been detected either in the RXTE or in the INTEGRAL data which puts interesting constraints on theories of magnetic field evolution in neutron star low-mass X-ray binaries.
- go to publisher's site
- DOI: 10.1051/0004-6361:20066457; eprintid: arXiv:astro-ph/0609776
If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library, or send a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible.