Discovery of multiple ultra-luminous X-ray sources in the galaxy KUG 0214-057

Discovery of multiple ultra - luminous X - ray sources in the galaxy KUG 0214 - 057

We report the serendipitous discovery of several unresolved X-ray sources lying in the prominent spiral arms of the galaxy KUG 0214-057 in XMM-Newton observations. The location of these X-ray sources strongly suggests that at least three, and possibly four, of these may be physically related to the galaxy. The luminosity of each of these sources at the distance of KUG 0214-057 is > 5 × 10 39 er...

Variability in Ultra-luminous X-ray Sources

Many upcoming surveys, particularly in the radio and optical domains, are designed to probe either the temporal and/or the spatial variability of a range of astronomical objects. In the light of these high resolution surveys, we review the subject of ultra-luminous X-ray (ULX) sources, which are thought to be accreting black holes for the most part. We also discuss the sub-class of ULXs known a...

Are Ultra Luminous X-Ray Sources Microblazars?

Low metallicity and ultra-luminous X-ray sources in the Cartwheel galaxy

Low-metallicity (Z < ∼ 0.05Z⊙) massive ( > ∼ 40M⊙) stars might end their life by directly collapsing into massive black holes (BHs, 30 < ∼ mBH/M⊙ < ∼ 80). More than ∼ 10 massive BHs might have been generated via this mechanism in the metal-poor ring galaxy Cartwheel, during the last ∼ 10 yr. We show that such BHs might power most of the ultra-luminous X-ray sources (ULXs) observed in the Cartwh...

Optical and Infrared Signatures of Ultra-luminous X-ray Sources

We have constructed a model to describe the optical emission from ultra-luminous Xray sources (ULXs). We assume a binary model with a black hole accreting matter from a Roche lobe filling companion star. We consider the effects of radiative transport and radiative equilibrium in the irradiated surfaces of both the star and a thin accretion disk. We have developed this model as a tool with which...