Related papers: Periodic X-ray sources in the Massive Globular Clu…
We present a systematic search for periodic X-ray sources in 10 Galactic globular clusters (GCs) utilizing deep archival Chandra observations. By applying the Gregory-Loredo algorithm, we detect 28 periodic signals among 27 independent…
We present 22 new (+3 confirmed) cataclysmic variables (CVs) in the non core-collapsed globular cluster 47 Tucanae (47 Tuc). The total number of CVs in the cluster is now 43, the largest sample in any globular cluster so far. For the…
We have detected 300 X-ray sources within the half-mass radius (2.79') of the globular cluster 47 Tucanae in a deep (281 ks) Chandra exposure. We perform photometry and simple spectral fitting for our detected sources, and construct…
We combined Chandra ACIS observations of the globular cluster 47 Tucanae (hereafter, 47 Tuc) from 2000, 2002, and 2014-15 to create a deeper X-ray source list, and study some of the faint radio millisecond pulsars (MSPs) present in this…
We present a systematic study of periodic X-ray sources in the Limiting Window (LW), a $\sim$70 arcmin$^2$ field representative of the inner Galactic bulge and the target of $\sim$1 Ms Chandra observations. Using the Gregory-Loredo…
Aims. We present the results of the analysis of five observations of the globular cluster 47 Tucanae (47 Tuc) with eROSITA (extended Roentgen Survey with an Imaging Telescope Array) on board Spektrum-Roentgen-Gamma (Spektr-RG, SRG). The aim…
W2 (CXOGlb J002415.8-720436) is a cataclysmic variable (CV) in the Galactic globular cluster 47 Tucanae. Its modulation was discovered within the CATS@BAR project. The source shows all the properties of magnetic CVs, but whether it is a…
We report time series and variability information for the optical identifications of X-ray sources in 47 Tuc reported in Paper I. The eight CVs with secure orbital periods have fainter accretion disks, in the V band, than field CVs with…
We report on the Chandra ACIS-S3 imaging observation of the globular cluster NGC 6752. We detect 6 X-ray sources within the 10.5" core radius and 13 more within the 115" half-mass radius down to a limiting luminosity of Lx approx 10^{30}…
For many years, it has been claimed that the Galactic ridge X-ray emission at the Galactic Center (GC) is truly diffuse in nature. However, with the advancement of modern X-ray satellites, it has been found that most of the diffuse emission…
Chandra observations of globular clusters provide insight into the formation, evolution, and X-ray emission mechanisms of X-ray binary populations. Our recent (2002) deep observations of 47 Tuc allow detailed study of its populations of…
We have monitored a sample of 27 nearby globular clusters in the hard X-ray band (20-120 keV) for approximately 1400 days using the BATSE instrument on board the Compton Gamma-Ray Observatory. Globular clusters may contain a large number of…
Five fields located close to the center of the globular cluster NGC 104=47 Tuc were surveyed in a search for variable stars. We present V-band light curves for 42 variables. This sample includes 13 RR Lyr stars -- 12 of them belong to the…
We report the largest number of optical identifications of X-ray sources yet obtained in a single globular cluster. Using deep Chandra/ACIS-I imaging and extensive HST studies with WFPC2, we have detected optical counterparts to at least 22…
[Abridged] We have discovered 10 periodic X-ray sources from the 1 Ms Chandra ACIS observation of the Limiting Window (LW), a low extinction region (A_V~3.9) at 1.4 Deg south of the Galactic center. The observed periods (~1.3 to 3.4 hours)…
Context. Observations of cataclysmic variables in globular clusters appear to show a dearth of outbursts compared to those observed in the field. A number of explanations have been proposed, including low mass-transfer rates and/or moderate…
Observations with BeppoSAX, RXTE and Chandra suggest that many of the bright X-ray sources in globular clusters have ultrashort binary periods. This is remarkable as such systems are not easily formed. With accurate optical astrometry of…
Based on over 5400 BV images of 47 Tuc collected between 1998 and 2010 we obtained light curves of 65 variables, 21 of which are newly detected objects. New variables are located mostly just outside of the core in a region poorly studied by…
Cataclysmic variables (CVs) are binary systems with a white dwarf accreting matter from a low-mass star, making them significant sources of X-ray emission in the Galaxy. We present a systematic search for X-ray emitting CV candidates by…
We investigate near-ultraviolet (NUV) variability in the Galactic globular cluster (GC) 47 Tucanae (47 Tuc). This work was undertaken within the GC sub-project of the Transient UV Objects project, a programme which aims to find and study…