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The Ultraluminous X-ray Sources NGC 1313 X-1 and X-2

R. Turolla·P. Mucciarelli·L. Zampieri·R. Falomo·M. Chieregato·A. Treves
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Abstract

We present a detailed analysis of XMM archival data of two Ultraluminous X-ray Sources (ULXs) in the nearby spiral galaxy NGC 1313: NGC 1313 X-1 and X-2. The spectral continuum of these sources was modeled with a soft thermal component plus a power-law. If the soft component originates from an accretion disk, the inferred mass of the compact remnant is > 100 M_sun, making it an Intermediate Mass Black Hole (IMBH). A detailed analysis of the residuals of the XMM EPIC-pn spectrum shows some evidence for the presence of an Oxygen emission line in NGC 1313 X-1. The simultaneous presence of an excess in emission, although at a much reduced significance level, at different energies in the X-ray spectra of NGC 1313 X-1 and X-2 is suggestive of typical emission lines from young supernova remnants. An optical counterpart for NGC 1313 X-2 was also identified. On an ESO 3.6 m image, the Chandra error box embraces a R \~ 23 mag stellar-like object and excludes a previously proposed optical counterpart.

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R. Turolla, P. Mucciarelli, L. Zampieri, R. Falomo, M. Chieregato, A. Treves. 2005-06-15. The Ultraluminous X-ray Sources NGC 1313 X-1 and X-2. https://doi.org/10.1016/j.asr.2005.06.028

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