XMM-Newton observations of the ultraluminous X-ray source NGC 1313 X-1

Ultraluminous X-ray sources (ULXs) are extra-galaxtic, non-nuclear sources with the X-ray luminosity in excess of the Eddington limit for a 10 M _⊙ black hole. Although some ULXs could be candidates for intermediate mass black holes accreting matter at sub-Eddington rate, it is thought that the majority population of ULXs are stellar mass black holes accreting matter at super-Eddington state. In this work, we examine the high quality X-ray spectra of the ULX NGC 1313 X-1 observed by XMM-Newton . The modeling results suggest that the data could be explained well using the super-Eddington model. Moreover, the X-ray spectral evolution of the ULX could be explained successfully in the context of accretion in the super-Eddington state. (paper)