相关论文: X-ray spectral evolution in M33 X-8
The results of a spectral analysis, using {\it XMM-Newton} and {\it Chandra} data of the brightest ultra luminous X-ray source in the nearby galaxy M82, are presented. The spectrum of M82 X-1, was found to be unusually hard (photon spectral…
We present an X-ray analysis of three different XMM-Newton observations together with simultaneous NICER and NuSTAR observations of the ultraluminous X-ray source NGC 4190 ULX-1. Our goal is to constrain the structure of the accretion disk…
Aims. We analyzed multi-epoch X-ray data of the Ultraluminous X-ray source (ULX) NGC 5055 X-1, with luminosity up to $2.32\times10^{40}\ \rm erg\ s^{-1}$, in order to constrain the physical parameters of the source. Methods. We performed…
We have analyzed the archival XMM-Newton data of the bright Ultra-Luminous X-ray Source (ULX) M82 X-1 with an 105 ksec exposure when the source was in the steady state. Thanks to the high photon statistics from the large effective area and…
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…
Studies of X-ray continuum emission and flux variability have not conclusively revealed the nature of ultra-luminous X-ray sources (ULXs) at the high-luminosity end of the distribution (those with Lx > 1e40 erg/s). These are of particular…
Most ultraluminous X-ray sources (ULXs) are believed to be stellar mass black holes or neutron stars accreting beyond the Eddington limit. Determining the nature of the compact object and the accretion mode from broadband spectroscopy is…
Supercritical accretion onto compact objects may drive massive winds that are nearly spherical, optically thick, and Eddington limited. Blackbody emission from the photosphere is the direct observational signature of the wind. Here we…
Winds are an important ingredient in the evolution of X-ray binary (XRB) systems, particularly those at high accretion rates such as ultra-luminous X-ray sources (ULXs), because they may regulate the accretion of matter onto the compact…
We report the detection of flaring events in NGC 4395 ULX1, a nearby ultraluminous X-ray source (ULX), for the first time, using recent XMM-NEWTON observations. The flaring episodes are spectrally harder than the steady emission intervals,…
In this letter, we comment on the robustness of putative cool (kT ~ 0.2 keV) accretion disc components in the X-ray spectra of the most luminous (L ~ 10^40 erg/s) ultra-luminous X-ray sources (ULXs) in nearby normal galaxies. When compared…
Ultraluminous X-ray sources (ULXs) are non-nuclear X-ray binary systems that exceed the Eddington luminosity for a 10 Msun black hole. The majority of these sources are thought to be stellar-mass compact objects accreting at super-Eddington…
The presence of a cool multicolor disk component with an inner disk temperature kT=0.1~0.3 keV at a luminosity L>10^40 erg/s has been interpreted as evidence that the ultraluminous X-ray source NGC 1313 X-2 harbors an intermediate-mass…
We report on the results of detailed spectral studies of the ultra-luminous X-ray source (ULX), M81 X-9 (Holmberg IX X-1), made with XMM-Newton on 2001 April 22 and with ASCA on 1999 April 6. On both occasions, the source showed an…
Ultra-luminous Compact X-ray Sources (ULXs) in nearby spiral galaxies and Galactic superluminal jet sources share the common spectral characteristic that they have unusually high disk temperatures which cannot be explained in the framework…
Ultraluminous X-ray sources (ULXs) are extreme X-ray binaries shining above 10^39 erg/s, in most cases as a consequence of super-Eddington accretion onto neutron stars and stellar-mass black holes accreting above their Eddington limit. This…
We report on XMM-Newton/Chandra/Swift/HST observations of the ultraluminous X-ray source (ULX) in NGC 247, which is found to make transitions between the supersoft ultraluminous (SSUL) regime with a spectrum dominated by a cool ($\sim 0.1$…
Ultraluminous X-ray sources (ULXs) represent the closest and most accessible laboratories to study sustained super-Eddington accretion onto compact objects. Over the past decade, the discoveries of coherent pulsations in a few ULXs has…
We present the results obtained by a detailed study of the extragalactic Z source, LMC X-2, using broad band Suzaku data and a large ($ \sim 750$ ksec) data set obtained with the proportional counter array (PCA) onboard RXTE. The PCA data…
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…