Related papers: Two new candidate ultra-compact X-ray binaries
We present X-ray and optical observations of a new transient X-ray source in M31 first detected 23-May-2004 at R.A.=00:43:09.940 +/- 0.65'', Dec.=41:23:32.49 +/- 0.66''. The X-ray lightcurve shows two peaks separated by several months,…
We report results from Hubble Space Telescope WFPC2 imaging of the field of the luminous, bursting X-ray source in the globular cluster NGC 6441. Although the X-ray position is known to a precision of a few arcseconds, this source is only…
We present a systematic analysis of archival HST WFPC2 ``Association'' data sets that correlate with the Chandra positions of a set of 44 ultra-luminous X-ray sources (ULXs) of nearby galaxies. We have improved the Chandra-HST relative…
Archival {\it XMM-Newton}, {\it Chandra} and {\it Hubble Space Telescope (HST)} data have been used to study the X-ray and optical properties of two candidate ultraluminous X-ray sources (ULXs) in NGC\,4536. In order to search for potential…
X-ray binaries provide exceptional laboratories for understanding the physics of matter under the most extreme conditions. Until recently, there were few, if any, observational constraints on the circumbinary environments of X-ray binaries…
We present two simultaneous NICER and NuSTAR observations of the ultra-compact X-ray binary (UCXB) candidate SLX 1735-269 while the source was in two different spectral states. Using various reflection modeling techniques, we find that…
We present the results of a search for optical counterparts of ultraluminous X-ray source (ULX) X-1 in the nearby galaxy NGC 2500 by using archival images taken with the Hubble Space Telescope ({\it HST}) Wide Field Camera (WFC3)/UVIS. Four…
We present the first joint NuSTAR and NICER observations of the ultra-compact X-ray binary (UCXB) 4U 0614+091. This source shows quasi-periodic flux variations on the timescale of ~days. We use reflection modeling techniques to study…
We used archival data from the \emph{Chandra X-ray Observatory} (\emph{Chandra}) and the \emph{Hubble Space Telescope}, to identify 334 candidate X-ray binary (XRB) systems and their potential optical counterparts in the interacting galaxy…
We present the results of our continued systematic search for near-infrared (NIR) candidate counterparts to ultraluminous X-ray sources (ULXs) within 10 Mpc. We observed 42 ULXs in 24 nearby galaxies and detected NIR candidate counterparts…
We identify the optical counterpart of the ultraluminous X-ray source (ULX) NGC 1313 X-1 and discuss constraints on its physical nature from multiband optical spectra. There is a single object on Hubble Space Telescope (HST) images within…
We present results of a search for optical counterparts of X-ray sources in and toward the globular cluster Omega Centauri (NGC 5139) using the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. The ACS data consist of a…
Ultracompact X-ray binaries (UCXBs) are a distinctive but elusive family of low-mass X-ray binaries (LMXBs) characterised by their tight orbits and degenerate donor stars. Here we present UltraCompCAT, the first online and comprehensive…
Symbiotic X-ray binaries form a subclass of low-mass X-ray binary systems consisting of a neutron star accreting material from a red giant donor star via stellar wind or Roche lobe overflow. Only a few confirmed members are currently known;…
We analyse a Chandra observation of the rich globular cluster NGC 362, finding 33 X-ray sources within 1' (1.2 half-mass radii) of the cluster center. Spectral analysis of the brightest source (X1) shows blackbody-like emission, indicating…
We re-examine the infrared counterpart of the dipping low-mass x-ray binary 4U1323-619. New X-ray data available from the XMM and Chandra observatories combined with archival IR observations from the ESO 3.6m New Technology Telescope allow…
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 discovery of several new OB/X-ray accreting binary candidates. These massive systems were found by cross-correlating in position SIMBAD OB star catalogues with the part of the ROSAT all-sky survey located at low galactic…
We report time-series photometry for 16 variable stars located in the central part of the globular cluster NGC 6752. The sample includes 13 newly identified objects. The precision of our differential photometry ranges from 1 mmag at V=14.0…
We model the present-day number and characteristics of Ultra-compact X-ray binaries (UCXBs) in the Galactic Bulge. The main objective is to compare the results with the forthcoming data from the Galactic Bulge Survey (GBS) in order to learn…