Physical Sciences and Mathematics Commons^™

Broad Relativistic Iron Emission Line Observed In Sax J1808.4-3658, E. M. Cackett, D. Altamirano, A. Patruno, J. M. Miller, M. Reynolds, M. Linares, R. Wijnands

Physics and Astronomy Faculty Research Publications

During the 2008 September-October outburst of the accreting millisecond pulsar SAX J1808.4-3658, the source was observed by both Suzaku and XMM-Newton approximately 1 day apart. Spectral analysis reveals a broad relativistic Fe Kα emission line which is present in both data sets, as has recently been reported for other neutron star low-mass X-ray binaries. The properties of the Fe K line observed during each observation are very similar. From modeling the Fe line, we determine the inner accretion disk radius to be 13.2 ± 2.5 GM c^-2. The inner disk radius measured from the Fe K line suggests …