X-rays: binariesUltraluminous X-ray sources (ULXs) were identified as a separate class of objects in 2000 based on data from the Chandra X-Ray Observatory. These are unique objects: their X-ray luminosities exceed the Eddington limit for a typical stellar-mass black hole. For a long time,...
X-rays: galaxiesUltraluminous X-ray sources (ULXs) are some of the brightest phenomena found outside of a galaxy's nucleus, and their explanation typically invokes accretion of material onto a black hole. Here, we perform the largest population study to date of ULXs in early-type galaxies, ...
Ultraluminous X-ray sources (ULXs) in nearby galaxies have stirred great interest in the high energy community because of their unresolved nature. ULXs are characterized by their high luminosities of 1E39-1E41 erg/sec, about 10 - 1000 times the Eddington luminosity for a neutron star. They ca...
X-ray pulsations with an average period of 1.37 seconds have been detected from a known ultraluminous X-ray source hitherto thought to be a black hole; the pulsations instead unequivocally identify the source as an accreting magnetized neutron star ten t
X-Rays: BinariesX-Rays: GalaxiesAn XMM-Newton study of ultraluminous X-ray sources (ULX) has been performed in a sample of 10 nearby Seyfert galaxies. Eighteen ULX have been found with positional uncertainty of about 4". The large collecting area of XMM-Newton makes the statistics ...
Ultraluminous X-ray sources (ULXs) are non-nuclear point-like objects observed with extremely high X-ray luminosity that exceeds the Eddington limit of a $m 10\, M_\odot$ black hole. A fraction of ULXs has been confirmed to contain neutron star (NS) accretors due to the discovery of ...
Russian astronomers have performed a detailed study of one of the ultraluminous X-ray sources (ULXs) in the galaxy UGC 6456. Results of the research, presented in a paper published November 20 on arXiv.org, suggest that this source, designated UGC 6456 ULX, is one of the brightest known...
We investigate models for the class of ultraluminous non-nuclear X-ray sources (ULXs) seen in a number of galaxies and probably associated with star-forming regions. Models where the X-ray emission is assumed to be isotropic run into several difficulties. In particular formation of sufficient nu...
NASA JPL –NASA Study Helps Explain Limit-Breaking Ultra-Luminous X-Ray Sources Bachetti et al –Orbital Decay in M82 X-2 UT –Astronomers See Evidence of Supermassive Black Holes Forming Directly in the Early Universe UT –Nearby Galaxy Holds First Ultraluminous X-Ray Source that is a Pulsar...
The discovery of hyperluminous X-ray sources has led to specu- lation that we may, once again, have found the elusive intermediate mass black holes, yet in the last year, a third sub-class of extreme ULXs has emerged, with their nature, as yet, un- known. Here we define and discuss...