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arXiv · 0903.3210

SAX J1808.4-3658: high resolution spectroscopy and decrease of pulsed fraction at low energies

Alessandro Patruno·Nanda Rea·Diego Altamirano·Manuel Linares·R. Wijnands·M. van der Klis
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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 2 keV, 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 2 keV 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.

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Alessandro Patruno, Nanda Rea, Diego Altamirano, Manuel Linares, R. Wijnands, M. van der Klis. 2009-03-18. SAX J1808.4-3658: high resolution spectroscopy and decrease of pulsed fraction at low energies. https://doi.org/10.1111/j.1745-3933.2009.00660.x

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