This information, derived from the Einstein X-ray Observatory Catalog of O-type Stars, by Chlebowski, Harnden and Sciortino, provides information regarding the Soft X-ray measurements for all normal, massive, O-type stars serveyed with The Einstein Observatory. More information is available through the HEASARC. This is a service provided by NASA HEASARC .

This table contains a source catalog based on XMM-Newton observations of the bright Local Group spiral galaxy M 31. In an analysis of XMM archival observations of M 31, the authors studied the population of X-ray sources (X-ray binaries, supernova remnants) down to a 0.2-4.5 keV luminosity of 4.4 x 10³⁴ erg/s. EPIC hardness ratios and optical and radio information were used to distinguish between different source classes. The survey detected 856 sources in an area of 1.24 square degrees. The authors correlated their sources with earlier M 31 X-ray catalogs and used information from optical, infra-red and radio wavelengths. As sources within M 31, they detected 21 supernova remnants (SNR) and 23 SNR candidates, 18 supersoft source (SSS) candidates, 7 X-ray binaries (XRBs) and 9 XRB candidates, as well as 27 globular cluster sources (GlC) and 10 GlC candidates, which most likely are low mass XRBs within the GlC. Comparison to earlier X-ray surveys revealed transients not detected with XMM-Newton, which add to the number of M 31 XRBs. There are 567 sources classified as hard, which might either be XRBs or Crab-like SNRs in M 31 or background AGN. The number of 44 SNRs and candidates more than doubles the X-ray-detected SNRs. 22 sources are new SNR candidates in M 31 based on X-ray selection criteria. Another SNR candidate might be the first plerion detected outside the Galaxy and the Magellanic Clouds. On the other hand, six sources are foreground stars and 90 are foreground star candidates, one is a BL Lac-type active galactic nucleus (AGN) and 36 are AGN candidates, one source coincides with the Local Group galaxy M 32, one with a background galaxy cluster (GCl) and another is a GCl candidate, all sources which are not connected with M31. In a second paper, the authors presented an extension to the original 2005 XMM-Newton X-ray source catalog of M 31 which contained 39 newly found sources. These sources have been added to the original 856 sources to make a combined catalog of 895 X-ray sources which is contained herein. This table was originally created by the HEASARC in May 2005 based on the CDS table J/A+A/434/483/ file table2.dat (sources numbered 1 to 856). It was updated by the HEASARC in June 2008 by adding the 39 sources from the CDS table J/A+A/480/599/ file table3.dat (sources numbered 857 to 895). This is a service provided by NASA HEASARC .

This table contains a source catalog based om XMM-Newton observations of the nearby galaxy M 33. In an XMM-Newton raster observation of this bright Local Group spiral galaxy, the authors studied the population of X-ray sources (X-ray binaries, supernova remnants) down to a 0.2-4.5 keV luminosity limit of 10³⁵ erg/s, more than a factor of 10 deeper than earlier ROSAT observations. European Photon Imaging Camera (EPIC) hardness ratios and optical and radio information are used to distinguish between different source classes. The survey detects 408 sources in an area of 0.80 square degree. The authors correlated these newly detected X-ray sources with earlier M 33 X-ray catalogs and information from optical, infra-red and radio wavelengths. As M 33 sources, theydetect 21 supernova remnants (SNR) and 23 SNR candidates, 5 super-soft sources and 2 X-ray binaries (XRBs). There are 267 sources classified as hard, which may either be XRBs or Crab-like SNRs in M 33 or background AGN. The 44 confirmed and candidate SNRs more than double the number of X-ray detected SNRs in M 33. 16 of these are proposed as SNR candidates from the X-ray data for the first time. On the other hand, there are several sources not connected to M 33: five foreground stars, 30 foreground star candidates, 12 active galactic nucleus candidates, one background galaxy and one background galaxy candidate. Extrapolating from deep field observations, 175 to 210 background sources are expected in this field. This indicates that about half of the sources which were detected are actually within M 33. This table was created by the HEASARC in October 2004 based on CDS table J/A+A/426/11/table3.dat This is a service provided by NASA HEASARC .

This table contains some of the results from an in-depth study of low-mass X-ray binaries (LMXBs) detected in the nearby lenticular galaxy NGC 3115 using the Megasecond Chandra X-ray Visionary Project observation (total exposure time 1.1 Ms). In total the authors found 136 candidate LMXBs in the field and 49 in globular clusters (GCs) above 2-sigma detection, with 0.3-8 keV luminosity L_X ~ 10³⁶ - 10³⁹ erg s^-1. Other than 13 transient candidates, the sources overall have less long-term variability at higher luminosity, at least at L_X >~ 2 x 10³⁷ erg s^-1. In order to identify the nature and spectral state of these sources, the authors compared their collective spectral properties based on single-component models (a simple power law or a multicolor disk) with the spectral evolution seen in representative Galactic LMXBs. The authors found that in the L_X vs. photon index Gamma_PL and L_X versus disk temperature kT_MCD plots, most of their sources fall on a narrow track in which the spectral shape hardens with increasing luminosity below L_X ~ 7 x 10³⁷ erg s^-1, but is relatively constant (Gamma_PL ~ 1.5 or kT_MCD ~ 1.5 keV) above this luminosity, which is similar to the spectral evolution of Galactic neutron star (NS) LMXBs in the soft state in the Chandra bandpass. Therefore, the authors identified the track as the NS LMXB soft-state track and suggested sources with L_X <~ 10³⁷ erg s^-1 as atolls in the soft state and those with L_X >~ 10³⁷ erg s^-1 as Z sources. Ten other sources (five are transients) displayed significantly softer spectra and are probably black hole X-ray binaries in the thermal state. One of them (a persistent source) is in a metal-poor GC. The 11 Chandra observations of NGC 3115 are listed in Table 1 of the reference paper. They were made during three epochs: one in 2001,two in 2010, and nine in 2012. All observations used the imaging array of the AXAF CCD Imaging Spectrometer (ACIS). This table contains the properties of the 482 detected point sources in the merged and single Chandra ACIS observations of NGC 3115 above a 2-sigma threshold and after eliminating a number of spurious sources associated with bright streaks on the ACIS-S1 chip and (in one case) on a CCD edge. 469 of these sources (indicated by values of obs_flag = '0') have a single entry in this table, based on their properties as derived from all of the available Chandra data for that position. There are 13 transient sources (having obs_flag = 'h') for which an additional entry is provided referring to their properties in the "high state", and based on the combination of their high-state observations, as shown in Figures 3(a) - 3(d) in the reference paper. For source number 198, there is a second additional entry provided referring to its properties in the "low state", and based on the combination of its low-state observations, as shown in Figure 3(c) in the reference paper. Thus, there are 496 entries (rows) in this table, i.e., 482 + 13 + 1. This table was created by the HEASARC in August 2015 based on the union of the machine-readable versions of Table 3 (the master source catalog) and Table 4 (the source counts, fluxes and hardness ratios in the merged observations) that were obtained from the ApJ web site. It does not contain the source counts and fluxes in the individual observations which were given in Table 5 of the reference paper. This is a service provided by NASA HEASARC .

The X-ray sources from observations made with the Einstein Observatory (HEAO-2) Imaging Proportional Counter (IPC) that have intensities of 2-sigma or more above the background are compiled in this catalog. This catalog covers more sky at fainter flux levels than the Einstein Medium Sensitivity Survey. Fields with diffuse emission sources such as bright Abell clusters of galaxies and supernova remnants were excluded. Thus, data within 10 degrees of the galactic plane as well as fields within the boundaries of the Magellanic Clouds were excluded. Regions crowded with galactic sources such as the Orion and Pleiades fiels were also excluded. Excluding redundant fields, this catalog covers 1850 sq. degrees of the sky. The generation of the Einstein Two-Sigma Catalog was described in detail by Moran et al. (1996). Please read this article carefully to ensure responsible use of the Catalog. Detailed scientific and technical questions on the contents and methodology of this catalog should be addressed to the first author, Ed Moran (edhed@igpp.llnl.gov). In particular, it should be noted that, by design, this catalog contains a significant number of spurious sources: only 28%, or about 13,000 sources, out of the 46,000 source in the 2-sigma catalog are `real` astrophysical sources, with the remainder of the sources being spurious ones. Moran et al. show in their paper that performing cross-correlations of 2-sigma sources with other catalogs is an effective way of selecting sources in this catalog that are probably real. This is a service provided by NASA HEASARC .

This table contains the results of a Chandra survey of low-mass X-ray binaries (LMXBs) in 24 early-type galaxies. Correcting for detection incompleteness, the X-ray luminosity function (XLF) of each galaxy is consistent with a power law with negative logarithmic differential slope, Beta, ~ 2.0. However, Beta strongly correlates with incompleteness, indicating the XLF flattens at low X-ray luminosity (L_X). The composite XLF is well fitted by a power law with a break at (2.21 [+0.65,-0.56]) x 10³⁸ erg s^-1 and Beta = 1.40 [+0.10,-0.13] and = 2.84 [+0.39,-0.30] below and above it, respectively. The break is close to the Eddington limit for a 1.4 solar-mass neutron star, but the XLF shape rules out its representing the division between neutron star and black hole systems. Although the XLFs are similar, the authors find evidence of some variation between galaxies. The high-L_X XLF slope does not correlate with age, but may correlate with [Alpha/Fe]. Considering only LMXBs with L_X > 10³⁷ erg s^-1, matching the LMXBs with globular clusters (GCs) identified in HST observations of 19 of the galaxies, the authors find the probability a GC hosts an LMXB is proportional to L_GC^Alpha Z_Fe^Gamma where Alpha = 1.01 +/- 0.19 and Gamma = 0.33 +/- 0.11. Correcting for GC luminosity and color effects, and detection incompleteness, they find no evidence that the fraction of LMXBs with L_X > 10³⁷ erg s^-1 in GCs (40%), or the fraction of GCs hosting LMXBs (~ 6.5%) varies between galaxies. The spatial distribution of LMXBs resembles that of GCs, and the specific frequency of LMXBs is proportional to the GC specific luminosity, consistent with the hypothesis that all LMXBs form in GCs. If the LMXB lifetime is Tau_L and the duty cycle is F_d, their results imply ~ 1.5(Tau_L/10⁸ yr)^-1 F_d^-1 LMXBs are formed per gigayear per GC, and they place an upper limit of one active LMXB in the field per 3.4 x 10⁹ solar luminosities of V-band luminosity. This table contains 1194 X-ray point sources that were detected within the B-band 25th magnitude ellipse D₂₅ (as listed in the de Vaucouleurs et al. Catalog of Bright Galaxies) of 24 early-type galaxies observed by Chandra (listed in Table 1 of the reference paper). The D₂₅ restriction should mitigate against contamination by background AGNs. This table was created by the HEASARC in February 2009 based on the electronic versions of Table 6 from the paper which was obtained from the Astrophysical Journal web site. This is a service provided by NASA HEASARC .

Following the advent of increasingly sensitive X-ray observatories, deep observations of early-type stars became possible. However, the results for only a few objects or clusters have until now been reported and there has been no large survey comparable to that based upon the ROSAT All-Sky Survey (RASS). A limited survey of X-ray sources, consisting of all public XMM observations (2XMMi) and slew survey data (XMMSL1), is now available. The X-ray counterparts to hot, massive stars have been searched for in these catalogs. About 300 OB stars were detected with XMM. Half of them were bright enough for a spectral analysis to be possible, and we make available the detailed spectral properties that were derived. The X-ray spectra of O stars are represented well by low (< 1 keV) temperature components and seem to indicate that an absorption column is present in addition to the interstellar contribution. The X-ray fluxes are well correlated with the bolometric fluxes, with a scatter comparable to that of the RASS studies and thus larger than found previously with XMM for some individual clusters. These results contrast with those of B stars that exhibit a large scatter in the L_X - L_bol relation, no additional absorption being found, and the fits indicate a plasma at higher temperatures. Variability (either within one exposure or between multiple exposures) was also investigated whenever possible: short-term variations are far more rare than long-term ones (the former affects a few percent of the sample, while the latter concerns between one third and two thirds of the sources). This is a catalog of X-ray emitters amongst early-type stars following a correlation between the Reed (2003, AJ, 125, 2531) Catalog of galactic OB Stars and the 2XMMi Catalog (Watson et al. 2009, A&A, 493, 339). See the reference paper for more details. This table was created by the HEASARC in November 2009 based on CDS table J/A+A/506/1055 file table1.dat. This is a service provided by NASA HEASARC .