SAXJ1808.4-3658: high-resolution spectroscopy and decrease of pulsed fraction at low energies
Abstract
XMM-Newton observed the accreting millisecond pulsar SAX J1808.4-3658 during its 2008 outburst. We present timing and spectral analyses of this observation, in particular the first pulse profile study below 2keV, and the high-resolution spectral analysis of this source during the outburst. Combined spectral and pulse profile analyses suggest the presence of a strong unpulsed source below 2keV that strongly reduces the pulsed fraction and a hard pulsed component that generates markedly double peaked profiles at higher energies. We also studied the high-resolution grating spectrum of SAX J1808.4-3658, and found several absorption edges and oxygen absorption lines with whom we infer, in a model independent way, the interstellar column densities of several elements in the direction of SAX J1808.4-3658.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- June 2009
- DOI:
- 10.1111/j.1745-3933.2009.00660.x
- arXiv:
- arXiv:0903.3210
- Bibcode:
- 2009MNRAS.396L..51P
- Keywords:
-
- pulsars: general;
- pulsars: individual: SAXJ1808.4-3658;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- MNRAS Letters, accepted