相关论文: Revisiting the ultraluminous supersoft source in M…

In this work, we study the X-ray spectral and temporal properties of an ultraluminous X-ray source (ULX) in NGC 628 by using multi-epoch archival X-ray data. The physical parameters were estimated in each epoch in order to constrain the…

Using Chandra observations we have identified a sample of seven off-nuclear X-ray sources, in the redshift range z=0.072-0.283, located within optically bright galaxies in the COSMOS Survey. Using the multi-wavelength coverage available in…

Using archival Hubble Space Telescope (HST) imaging data, we report the multiband photometric properties of 13 ultraluminous X-ray sources (ULXs) that have a unique compact optical counterpart. Both magnitude and color variation are…

Transient ultraluminous X-ray sources (ULXs) provide an important link bridging transient low-mass X-ray binaries and ULXs. Here we report the first discovery of both a canonical sub-Eddington outburst and an ultraluminous super-Eddington…

We have analysed the soft X-ray emission from the nuclear source of the nearby spiral galaxy M81, using the available data collected with ROSAT, ASCA, BeppoSAX and Chandra. The source flux is highly variable, showing (sometimes dramatic: a…

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 report the identification of a recurrent ultraluminous X-ray source (ULX), a highly absorbed X-ray source (possibly a background AGN), and a young supernova remnant near the center of the starburst galaxy M82. From a series of Chandra…

A deep (98.2 ks) Chandra Cycle-1 observation has revealed a wealth of discrete X-ray sources as well as diffuse emission in the nearby face-on spiral galaxy M101. From this rich dataset we have created a catalog of the 110 sources from the…

We investigate outflows and the physics of super-Eddington versus sub-Eddington regimes in black hole systems. Our focus is on prospective science using next-generation high-resolution soft X-ray instruments. We highlight the properties of…

We present a set of controlled hydrodynamical simulations to study the effects of strong galactic outflows on the density and temperature structures, and associated X-ray signatures, of extra-planar and circumgalactic gas. We consider three…

Ultra-luminous X-ray sources (ULXs) are those X-ray sources located away from the centre of their host galaxy with luminosities exceeding the Eddington limit of a stellar-mass black hole ($L_X>10^{39}\;{\rm erg\,s}^{-1}$). The discovery of…

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…

We derive the luminosity-temperature relation for the super-critically accreting black holes (BHs) and compare it to the data on ultraluminous X-ray sources (ULXs). At super-Eddington accretion rates, an outflow forms within the…

NGC 925 ULX-1 and ULX-2 are two ultraluminous X-ray sources in the galaxy NGC 925, at a distance of 8.5 Mpc. For the first time, we analyzed high quality, simultaneous XMM-Newton and NuSTAR data of both sources. Although at a first glance…

We report the results of an analysis of two XMM-Newton/EPIC-pn spectra of the bright ultraluminous X-ray source M81 X-9 (Holmberg IX X-1), obtained in snapshot observations. Soft thermal emission is clearly revealed in spectra dominated by…

X-ray continuum spectra of super-Eddington accretion flow are studied by means of Monte Carlo radiative transfer simulations based on the radiation hydrodynamic simulation data, in which both of thermal and bulk Compton scatterings are…

The nature of ultraluminous X-ray sources (ULXs) is not yet fully understood but it can be done in the most efficient way by analyzing its optical emission and environment. We present preliminary results of photometric and spectral studies…

Most ultraluminous X-ray sources (ULXs) are thought to be supercritical accreting compact objects, where massive outflows are inevitable. Using the long-term monitoring data with the Swift X-ray Telescope, we identified a common feature in…

Supersoft X-ray sources (SSS) are thought to be accreting white dwarfs (WDs) in close binary systems, with thermonuclear burning on their surfaces. The SSS RX J0513.9-6951 in the Large Magellanic Cloud (LMC) exhibits cyclic variations…

Two {\it ASCA} observations were made of two ultra-luminous compact X-ray sources (ULXs), Source 1 and Source 2, in the spiral galaxy IC 342. In the 1993 observation, Source 2 showed a 0.5--10 keV luminosity of $6 \times 10^{39}$ ergs…