This is the Fourth Edition of the Catalog of Low-mass X-ray Binaries (LMXBs) in the Galaxy and the Magellanic Clouds. The catalog has a companion catalog of high-mass X-ray binaries (HMXBs) which is called HMXBCAT in the HEASARC database system). The catalog contains source name(s), coordinates, X-ray flux, system parameters, and stellar parameters of the components and other characteristic properties of 187 low-mass X-ray binaries, together with references to a comprehensive selection of the relevant literature. The aim of this catalog is to provide some basic information on the X-ray sources and their counterparts in other wavelength ranges (gamma-rays, UV, optical, IR, and radio). Some sources, however, are only tentatively identified as low-mass X-ray binaries on the basis of their X-ray properties being similar to the known low-mass X-ray binaries. Further identification in other wavelength bands is needed to finally determine the nature of these sources. In cases where there is some doubt about the low-mass nature of the X-ray binary, this is mentioned. Literature published before 1 October 2006 has, as far as possible, been taken into account. This online catalog was created by the HEASARC in September 2007 based on machine-readable tables obtained from the ADC/CDS data centers (their catalog J/A+A/469/807, tables lmxb.dat and lmxbnote.dat). This is a service provided by NASA HEASARC .

The XRAY database table contains selected parameters from almost all HEASARC X-ray catalogs that have source positions located to better than a few arcminutes. The XRAY database table was created by copying all of the entries and common parameters from the tables listed in the Component Tables section. The XRAY database table has many entries but relatively few parameters; it provides users with general information about X-ray sources, obtained from a variety of catalogs. XRAY is especially suitable for cone searches and cross-correlations with other databases. Each entry in XRAY has a parameter called 'database_table' which indicates from which original database the entry was copied; users can browse that original table should they wish to examine all of the parameter fields for a particular entry. For some entries in XRAY, some of the parameter fields may be blank (or have zero values); this indicates that the original database table did not contain that particular parameter or that it had this same value there. The HEASARC in certain instances has included X-ray sources for which the quoted value for the specified band is an upper limit rather than a detection. The HEASARC recommends that the user should always check the original tables to get the complete information about the properties of the sources listed in the XRAY master source list. This master catalog is updated periodically whenever one of the component database tables is modified or a new component database table is added. This is a service provided by NASA HEASARC .

This table contains a catalog of 312 X-ray selected BL Lacertae objects (XBLs), optically identified through the end of 2011. It contains the names from different surveys, equatorial coordinates, redshifts, multi-frequency flux values, and luminosities for each source. In the reference, the different characteristics of these XBLs are statistically investigated (redshift, radio/optical/X-ray luminosities, central black hole (BH) mass, synchrotron peak frequency, broadband spectral indices, optical flux variability). Their values were collected through an extensive bibliographic and database search or calculated by the author. The redshifts range from 0.031 to 0.702 with a maximum of the distribution at z = 0.223. The 1.4-GHz luminosities of XBLs log (nu * L_nu) ~ 39 - 42 (in units of erg s^-1), while the optical V and X-ray (0.1-2.4 keV) bands show log (nu * L_nu) ~ 43 - 46 (same units). The XBL hosts are elliptical galaxies with effective radii r_eff = 3.26 - 25.40 kpc and ellipticities e = 0.04 - 0.52. Their R-band absolute magnitudes M_R range from -21.11 mag to -24.86 mag with a mean value of -22.83 mag. The V - R indices of the hosts range from 0.61 to 1.52 and reveal a fourth-degree polynomial relationship with z that enabled the author to evaluate the redshifts of five sources whose V - R indices were determined from the observations, but whose redshifts values are either not found or not confirmed. The XBL nuclei show a wider range of 7.31 mag for M_R, with the highest luminosity corresponding to M_R = -27.24 mag. The masses of the central BHs are found in the interval log M_BH = 7.39 - 9.30 (in units of solar masses), with the maximum of the distribution at log M_BH/M_sun = 8.30. The synchrotron peak frequencies are spread over the range log nu_peak = 14.56 - 19.18 Hz, with a peak of the distribution at log nu_peak = 16.60 Hz. The broad-band radio-to-optical (alpha_ro), optical-to-X-ray (alpha_ox), and radio-to-X-ray (alpha_rx) spectral indices are distributed in the intervals (0.17, 0.59), (0.56, 1.48), and (0.41, 0.75), respectively. In the optical energy range, the overall flux variability increases, on average, towards shorter wavelengths: Delta(m) = 1.22, 1.50, and 1.82 through the R, V, B bands of the Johnson-Cousins system, respectively. XBLs seem be optically less variable at intranight timescales compared to radio-selected BL Lacs (RBLs). This table was created by the HEASARC in June 2013 based on an electronic version of Table 2 from the reference paper which was obtained form the AJ web site. This is a service provided by NASA HEASARC .

This table contains the XMM-Newton EPIC COSMOS X-ray point-like source catalog (XMM-COSMOS). The COSMOS survey is a multiwavelength survey aimed to study the evolution of galaxies, AGN and large scale structures. Within this survey, XMM-COSMOS is a powerful tool for detecting AGN and galaxy clusters. The XMM-COSMOS is a deep X-ray survey over the full 2 deg² of the COSMOS area. It consists of 55 XMM-Newton pointings for a total exposure of ~1.5 Ms with an average vignetting-corrected depth of 40 ks across the field of view and a sky coverage of 2.13 deg². The analysis was performed using the XMM-SAS data analysis package in the 0.5-2 keV, 2-10 keV and 5-10 keV energy bands. Source detection has been performed using a maximum likelihood technique especially designed for raster scan surveys. The completeness of the catalog as well as log N-log S and source density maps have been calibrated using Monte Carlo simulations. This is the catalogue of point-like X-ray sources detected with the EPIC CCD cameras. The catalogs contains a total of 1887 unique sources detected in at least one band with likelihood parameter det_ml > 10. The survey, which shows unprecedented homogeneity, has a flux limit of ~1.7 x 10^-15 erg/cm²/s, ~9.3 x 10^-15 erg/cm²/s and ~1.3 x 10^-14 erg/cm²/s over 90% of the area (1.92 deg²) in the 0.5-2 keV, 2-10 keV and 5-10 keV energy bands, respectively. This table was created by the HEASARC in April 2009 based on the electronic version of Table 3 from the paper which was obtained from the CDS (their catalog J/A+A/497/635 file catalog.dat). It was last updated in May 2010 to correct the source number for XMMU J100100.7+015947 to be XMMC 129, as indicated by SIMBAD. This is a service provided by NASA HEASARC .