Related papers: An Ultraluminous X-ray Source Powered by An Accret…
A fraction of the Ultra Luminous X-ray (ULX) sources are known to be accreting neutron stars as they show coherent X-ray pulsations with pulse periods ranging from ~1-30 seconds. While initially thought to host intermediate-mass black…
In order to explain unusually high luminosity and spectral nature of ultra-luminous X-ray sources (ULXs), some of the underlying black holes are argued to be of intermediate mass, between several tens to million solar masses. Indeed, there…
Ultraluminous x-ray sources (ULXs) in nearby galaxies shine brighter than any X-ray source in our Galaxy. ULXs are usually modeled as stellar-mass black holes (BHs) accreting at very high rates or intermediate-mass BHs. We present…
The origin of Ultraluminous X-ray Sources (ULXs) in external galaxies whose X-ray luminosities exceed those of the brightest black holes in our Galaxy by hundreds and thousands of times is mysterious. The most popular models for the ULXs…
Ultra-luminous X-ray sources (ULXs) have been puzzling us with a debate whether they consist of an intermediate mass black hole or super-Eddington accretion by a stellar mass black hole. Here we suggest that in the presence of large scale…
The discovery of pulsations in several Ultraluminous X-ray sources (ULXs) demonstrated that a fraction of ULXs are powered by super-Eddington accretion onto neutron stars (NSs). This opened the debate as to what is the NS to black hole (BH)…
We consider ultraluminous X-ray sources (ULXs) where the accretor is a neutron star rather than a black hole. We show that the recently-discovered example (M82 X-2) fits naturally into the simple picture of ULXs as beamed X-ray sources fed…
The origin of Ultraluminous X-ray sources (ULXs) in external galaxies whose X-ray luminosities exceed those of the brightest black holes in our Galaxy by hundreds and thousands of times is mysterious. The most popular models for the ULXs…
Ultraluminous X-ray sources (ULXs) are mostly extragalactic non-nuclear point sources having X-ray luminosity exceeding the Eddington luminosity of 10 $M_\odot$ black hole i.e., $L_X \geq $ 10$^{39}$ erg ~s$^{-1}$. They are observed in all…
Ultraluminous X-ray sources (ULXs) are X-ray binary systems containing an accreting neutron star (NS) or black hole emitting at luminosities above the Eddington limit of a $10M_{\odot}$ black hole. Approximately 1900 (either confirmed or…
The classical limit on the accretion luminosity of a neutron star is given by the Eddington luminosity. The advanced models of accretion onto magnetized neutron stars account for the appearance of magnetically confined accretion columns and…
We study the evolution of newborn neutron stars in high-mass X-ray binaries interacting with a wind-fed super-Eddington disk. The inner disk is regularized to a radiation-dominated quasi-spherical configuration for which we calculate the…
The discovery of pulsating ultra-luminous X-ray sources (PULX) suggests that neutron stars are presumably common within the ultra-luminous X-ray source (ULX) population though the majority of the population members are currently lacking…
We present some results from an archival VLA study of ultraluminous X-ray source s (ULXs). These unresolved non-nuclear X-ray sources have luminosities (L_X >= 1 0^39 ergs/sec) which may require somewhat exotic explanations, such as…
The nature of ultra-luminous X-ray sources (ULXs), which are off-nuclear extragalactic X-ray sources that exceed the Eddington luminosity for a stellar-mass black hole, is still largely unknown. They might be black hole X-ray binaries in a…
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 $\rm10\,M_\odot$ black hole. A fraction of ULXs has been confirmed to contain neutron…
Ultraluminous X-ray sources (ULXs) are accreting black holes that may contain the missing population of intermediate mass black holes or reflect super-Eddington accretion physics. Ten years of Chandra and XMM-Newton observations of ULXs,…
The radiation spectra of many of the brightest ultraluminous X-ray sources (ULXs) are dominated by a hard power law component, likely powered by a hot, optically thin corona that Comptonizes soft seed photons emitted from a cool, optically…
The luminosity range at and just below the 10^39 erg/s cut-off for defining ultraluminous X-ray sources (ULXs) is a little-explored regime. It none-the-less hosts a large number of X-ray sources, and has great potential for improving our…
The identification of the Ultraluminous X-ray source (ULX) X-2 in M82 as an accreting pulsar has shed new light on the nature of a subset of ULXs, while rising new questions on the nature of the super-Eddington accretion. Here, by…