相关论文: Discovery and analysis of a ULX nebula in NGC 3521

We report on Chandra observations of the bright ultra-luminous X-ray (ULX) source in NGC3921. Previous XMM observations reported in the literature show the presence of a bright ULX at a 0.5-10 keV luminosity of 2x10^40 erg/s. Our Chandra…

We present optical observations of a ULX in the nearby spiral galaxy IC 342. This variable source has an average X-ray luminosity of some 10^{40} erg/s. At the position of the source there is an ionized nebula (the "Tooth") having huge…

Despite much observational and theoretical effort little is presently known about the nature of the luminous non-nuclear X-ray sources which appear to largely surpass the Eddington limit of a few solar masses. Here we present first results…

We present the identification and characterization of the optical counterpart to 2XMM J011942.7+032421, one of the most luminous and distant ultra-luminous X-ray sources (ULXs). The counterpart is located near a star forming region in a…

We present the results of optical panoramic and long-slit spectroscopy of the nebula MF16 associated with the Ultraluminous X-ray Source NGC6946 ULX-1. More than 20 new emission lines are identified in the spectra. Using characteristic line…

We present the discovery and interpretation of ionized nebulae around two ultraluminous X-ray sources in M 51; both sources share the rare property of showing X-ray eclipses by their companion stars, and are therefore prime targets for…

The emission-line dwarf galaxy NGC 3413 is known to host a bright X-ray source near its optical center. The 0.3-10 keV luminosity of this source is estimated to be approximately 10$^{39}$ erg$s^{-1}$ potentially qualifying it as an…

Optical photometric and spectroscopic data are presented that show an association of an ultraluminous X-ray source in NGC 7331 with a young star cluster of mass 1.1e5 solar masses and age 4.25 Myr. If the ULX is part of the bright stellar…

We present radio through X-ray results of a bright (10^{40} erg/s in the 0.5 to 8.0 keV band) ultraluminous X-ray source (ULX), CXOU J153434.9+151149, in the starburst, interacting pair of galaxies NGC 5953/5954. Chandra image of this ULX…

We present a study of a peculiar nebula MF16 associated with an Ultraluminous X-ray Source NGC6946 ULX-1. We use integral-field and long-slit spectral data obtained with the 6-m telescope (Russia). The nebula was for a long time considered…

We report the discovery of a new ultraluminous X-ray source (ULX) in the nearby galaxy NGC 4244 from Chandra archival data. The source, 1WGAJ1216.9+3743, is one of the least luminous and softest ULXs discovered so far. Its X-ray spectrum is…

We present optical observations of an ultraluminous X-ray source (ULX) in Holmberg IX, a dwarf galaxy near M81. The ULX has an average X-ray luminosity of some 10^{40} erg/s. It is located in a huge (400pc x 300pc) ionized nebula being much…

Ultra-luminous X-Ray sources are extra-nuclear point sources in external galaxies with $L_X=10^{39}$--$10^{41}$ erg/s and are among the most poorly understood X-ray sources. To help understand their nature, we are trying to identify their…

We report the detection of radio emission coincident with the ultraluminous X-ray source (ULX) in Holmberg II. The radio emission is diffuse and resolved, covering an area ~60 by 40 pc in extent and well-matched to the recently discovered…

We present optical integral field observations of the H II region containing the ultraluminous X-ray source Holmberg II X-1. We confirm the existence of an X-ray ionized nebula as the counterpart of the source due to the detection of an…

We report the X-ray data analysis of two transient ultraluminous X-ray sources (ULXs, hereafter X1 and X2) located in the nearby galaxy NGC 7090. While they were not detected in the 2004 XMM-Newton and 2005 Chandra observations, their…

We report the results of a 2-month campaign conducted with the Chandra X-ray observatory to monitor the ultraluminous X-ray source (ULX) NGC 5204 X-1. This was composed of a 50-ks observation, followed by ten 5-ks follow-ups spaced…

To further understand the nature of the optical counterparts associated with Ultraluminous X-Ray sources (ULXs), we obtained far ultraviolet spectra of the reported counterparts to the ULXs in NGC 1313, Holmberg II, NGC 5204, and M81. The…

Ultraluminous X-ray sources (ULXs) are extragalactic X-ray emitters located off-center of their host galaxy and with a luminosity in excess of a few ${10^{39}\text{ erg s}^{-1}}$, if emitted isotropically. The discovery of periodic…

Since their discovery, Ultraluminous X-ray sources (ULXs) have attracted attention due to their combination of extreme luminosities and extra-nuclear locations. However, they are a fairly rare phenomenon, and attempts to investigate the…