Related papers: Ultraluminous X-ray Sources in M51

We present Chandra and XMM-Newton X-ray data of NGC5253, a local starbursting dwarf elliptical galaxy, in the early stages of a starburst episode. Contributions to the X-ray emission come from discrete point sources and extended diffuse…

The Chandra X-ray Observatory obtained a 50-ks observation of the central region of M81 using the ACIS-S in imaging mode. The global properties of the 97 x-ray sources detected in the inner 8.3x8.3 arcmin field of M81 are examined. Roughly…

This catalog comprises an up-to-date list of luminous (>10^36 erg/s) supersoft X-ray sources. We include in this catalog accreting binary sources of high luminosity which are thought to be in a state of (steady or recurrent) hydrogen…

We report on exploratory Chandra observations of five galactic nuclei that were found to be X-ray bright during the ROSAT all-sky survey (with L_X > 10^43 erg s^-1) but subsequently exhibited a dramatic decline in X-ray luminosity. Very…

New HST observations show that the bright X-ray source in the face-on spiral galaxy NGC 1073 is located near a ring of recent star formation with an age of 8-16 Myr. This strengthens the association of X-ray sources in spiral galaxies…

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…

The nearby barred spiral galaxy NGC 1313 has been observed with the PSPC instr- ument on board the ROSAT X-ray satellite. Ten individual sources are found. Three sources (X-1, X-2 and X-3 [SN~1978K]) are very bright (~10^40 erg/s) and are…

We detected a major X-ray outburst from M82 with a duration of 79 days, an average flux of 5E-11 erg cm^-2 s^-1 in the 2-10 keV band, and strong variability. The X-ray spectrum remained hard throughout the outburst. We obtained a Chandra…

NGC 55 ULX1 is a bright Ultraluminous X-ray source located 1.78 Mpc away. We analysed a sample of 20 Swift observations, taken between 2013 April and August, and two Chandra observations taken in 2001 September and 2004 June. We found only…

We present an analysis of the X-ray bright point source population in 43 massive clusters of galaxies observed with the Chandra X-ray Observatory. We have constructed a catalog of 4210 rigorously selected X-ray point sources in these…

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 have detected three new x-ray point sources, in addition to the known low-mass x-ray binary (LMXB) X1832-330, in the globular cluster NGC 6652 with a Chandra 1.6 ksec HRC-I exposure. Star 49 (M_{V}~4.7), suggested by Deutsch et al.(1998)…

In this paper we present the source list for 3 Chandra observations of the Local Group galaxy M33. The observations are centered on the nucleus and on the star forming region NGC 604. We detect a total of 261 sources in an area of \~0.2…

We present followup optical g', r', and i', imaging and spectroscopy of serendipitous X-ray sources detected in 6 archival Chandra, images included in the Chandra, Multiwavelength Project (ChaMP). Of the 486 X-ray sources detected between…

We report preliminary results from an arcsecond-resolution X-ray survey of nearby galaxies using ACIS on board Chandra. The total sample consists of 41 low-luminosity AGNs, including Seyferts, LINERs, and LINER/H II transition objects. In…

Using the Chandra ACIS-I instruments, we have carried out the deepest X-ray observation on a typical Galactic plane region at l 28.5 deg, where no discrete X-ray sources have been known previously. We have detected, as well as strong…

The relatively nearby (distance=24.1 Mpc) elliptical galaxy NGC821, hosting a central massive black hole but inactive at all wavelengths, was observed with Chandra for a total exposure of 230 ksec, to search for nuclear emission and gas…

We present an analysis of 15 Chandra observations of the nearby spiral galaxy M81 taken over the course of six weeks in May--July 2005. Each observation reaches a sensitivity of ~10^37 erg/s. With these observations and one previous deeper…

We present optical spectra and near-infrared imaging of a sample of serendipitous X-ray sources detected in the field of Chandra observations of the A2390 cluster of galaxies. The sources have 0.5-7 keV fluxes of 0.6-8 x 10^{-14} erg…

We have searched for unresolved X-ray sources in the vicinity of two rich clusters of galaxies: Abell 1995 (A1995) and MS 0451.6-0305 (MS0451), using the Chandra X-ray observatory. We detected significantly more unresolved sources around…