相关论文: A transient ultraluminous X-ray source in NGC 55

The number of Ultraluminous X-ray Sources (ULXs) is observed to be correlated with the current star formation rate in late-type galaxies and with the stellar mass in early-type galaxies (ETGs). Since there is very little gas, dust or star…

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…

We examined spectral evolution in ultraluminous X-ray sources (ULXs) with apparent luminosities of about 10^40 ergs/s. Based on new results in this paper and those reported in the literature, two common spectral behaviors were found. Some…

We examined X-ray spectral and timing properties of ultraluminous X-ray sources (ULXs) in nearby galaxies in XMM-Newton archival data. There appear to be three distinct classes of spectra. One class shows emission from hot, diffuse plasma.…

Ultraluminous X-ray sources (ULXs) with luminosities lying between ~3x10^{39} - 2x10^{40} erg/s represent a contentious sample of objects as their brightness, together with a lack of unambiguous mass estimates for the vast majority of the…

Ultraluminous and hyperluminous X-ray sources (ULXs and HLXs) are among the brightest astrophysical objects in the X-ray sky. While ULXs most likely host stellar-mass compact objects accreting at super-Eddington rates, HLXs are compelling…

We review observations of ultraluminous X-ray sources (ULXs). X-ray spectroscopic and timing studies of ULXs suggest a new accretion state distinct from those seen in Galactic stellar-mass black hole binaries. The detection of coherent…

We have studied a highly variable ultraluminous X-ray source (ULX) in the Fornax galaxy NGC 1365, with a series of 12 Chandra and XMM-Newton observations between 2002 and 2006. In 2006 April, the source peaked at a luminosity ~ 3 x 10^{40}…

We present 26 point-sources discovered with Chandra within 200" (~20kpc) of the center of the barred supergiant galaxy NGC 1365. The majority of these sources are high-mass X-ray binaries, containing a neutron star or a black hole accreting…

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 have searched for ultraluminous X-ray sources (ULXs) in a sample of 28 elliptical and S0 galaxies observed with Chandra. We find that the number of X-ray sources detected at a flux level that would correspond to a 0.3-10 keV X-ray…

One hundred fifty-four discrete non-nuclear Ultra-Luminous X-ray (ULX) sources, with intrinsic X-ray luminosities >1e39 ergs/s, are identified in 82 galaxies observed with Chandra's Advanced CCD Imaging Spectrometer. Source positions, X-ray…

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…

Constraining the astrophysical nature of Ultra-Luminous X-ray (ULX) sources, which have X-ray luminosities exceeding 10^39 erg/s, has been elusive due to the optical faintness of any counterparts. With high spectral resolution observations…

We present an analysis of recent XMM-Newton and HST archive data of the ultraluminous X-ray source NGC 1313 X-2. Quasi-simultaneous observations taken with XMM-Newton, HST and VLT allow us to study both the X-ray light curve and its…

We report here the discovery of NGC 7793 ULX-4, a new transient ultraluminous X-ray source (ULX) in NGC 7793, a spiral galaxy already well known for harbouring several ULXs. This new source underwent an outburst in 2012, when it was…

Ultraluminous pulsars are a definite proof that persistent super-Eddington accretion occurs in nature. They support the scenario according to which most Ultraluminous X-ray Sources (ULXs) are super-Eddington accretors of stellar mass rather…

Motivated by the recent discoveries that six Ultraluminous X-ray Sources (ULXs) are powered by highly super-Eddington X-ray pulsars, we searched for additional pulsating ULX (PULX) candidates by identifying sources that exhibit long-term…

We present a multi-mission X-ray analysis of a bright (peak observed 0.3-10 keV luminosity of ~ 6x10^{40} erg s^{-1}), but relatively highly absorbed ULX in the edge-on spiral galaxy NGC 5907. The ULX is spectrally hard in X-rays (Gamma ~…

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…