题目：X-ray Spectral and Optical Properties of Ultra Luminous X-ray Sources in Nearby Galaxies
报告人：Prof. Aysun Akyuz
(Department of Physics, University of Cukurova, Adana, Turkey)
摘要：Ultraluminous X-ray sources (ULXs) are variable, nonnuclear X-ray sources with isotropic luminosities (Lx > 1039 erg s-1) above the Eddington limit for a 10 (M⊙ ) black hole. In this presentation, I will review the main properties of ULXs and their popular spectral models. As part of our work, spectral and temporal characteristics of some ULXs are presented.?Also? the properties of the optical counterparts and constraints on their physical nature from multiband optical spectra are discussed.