X-ray reflection in a sample of X-ray bright Ultraluminous X-ray sources

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• Maria Caballero-Garcia, IoA
• Wednesday 16 September 2009, 17:00-17:15
• Sackler Lecture Theatre, IoA.

If you have a question about this talk, please contact Alexander Blustin.

We apply a reflection-based model to the best available XMM -Newton spectra of X-ray bright Ultraluminous X-ray (ULX) sources (NGC 1313 X-1, NGC 1313 X -2, M 81 X -6, Holmberg IX X -1, NGC 5408 X -1 and Holmberg II X -1). A spectral drop is apparent in the data of all the sources at energies 6-7 keV. The drop is interpreted here in terms of relativistically blurred ionized reflection from the accretion disk. A soft-excess is also detected from these sources (as usually found in the spectra of AGN ), with emission from O K and Fe L, in the case of NGC 5408 X -1 and Holmberg II X -1, which can be understood as features arising from reflection of the disk. Remarkably, ionized disk reflection and the associated powerlaw continuum provide a good description of the broad-band spectrum, including the soft-excess. With exception of NGC 1313 X -2 and M81 X -6, there is no requirement for thermal emission from the inner disk in the description of the spectra. The black holes of these systems must then be highly spinning, with a spin close to the maximum rate of a maximal spinning black hole. The results require the action of strong light bending in these sources.We discuss our results in terms of the masses of the black holes.

This talk is part of the New Results in X-ray Astronomy 2009 series.

This talk is included in these lists:

• Combined External Astrophysics Talks DAMTP
• Cosmology, Astrophysics and General Relativity
• Institute of Astronomy One-day Meetings
• Institute of Astronomy Talk Lists
• New Results in X-ray Astronomy 2009
• Sackler Lecture Theatre, IoA

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