The authors have analyzed Chandra ACIS observations of 32 nearby spiral and elliptical galaxies. The properties (e.g., counts in 3 energy bands, hardness ratios and inferred X-ray luminosities) of the 1441 X-ray point sources that were detected in these galaxies are listed in this table. The total point-source X-ray (0.3 - 8.0 keV) luminosity L_XP is found to be well correlated with the B-band, K-band, and FIR+UV luminosities of spiral host galaxies, and is well correlated with the B-band and K-band luminosities of elliptical galaxies. This suggests an intimate connection between L_XP and both the old and the young stellar populations, for which K and FIR+UV luminosities are reasonable proxies for the galaxy mass and the star formation rate (SFR). This table was created by the HEASARC in October 2006 based on CDS table J/ApJ/602/231/tablea1.dat This is a service provided by NASA HEASARC .

This table contains a catalog of 9017 X-ray sources identified in Chandra observations of a 2 degrees by 0.8 degrees field around the Galactic center. This enlarges the number of known X-ray sources in the region by a factor of 2.5. The catalog incorporates all of the ACIS-I observations as of 2007 August, which total 2.25 Ms of exposure. At the distance to the Galactic center (8 kpc), we are sensitive to sources with luminosities of 4 x 10³² erg s^-1 (0.5-8.0 keV; 90% confidence) over an area of 1 degree², and up to an order of magnitude more sensitive in the deepest exposure (1.0 Ms) around Sgr A*. The positions of 60% of the sources are accurate to <1 arcsecond (95% confidence), and 20% have positions accurate to <0.5 arcsec. The authors search for variable sources, and find that 3% exhibit flux variations within an observation, and 10% exhibit variations from observation-to-observation. They also find one source, CXOUGC J174622.7-285218, with a periodic 1745 s signal (1.4% chance probability), which is probably a magnetically accreting cataclysmic variable. The authors compare the spatial distribution of X-ray sources to a model for the stellar distribution, and find 2.8 sigma evidence for excesses in the numbers of X-ray sources in the region of recent star formation encompassed by the Arches, Quintuplet, and Galactic center star clusters. These excess sources are also seen in the luminosity distribution of the X-ray sources, which is flatter near the Arches and Quintuplet than elsewhere in the field. These excess point sources, along with a similar longitudinal asymmetry in the distribution of diffuse iron emission that has been reported by other authors, probably have their origin in the young stars that are prominent at a galactic lonitude ~ 0.1 degrees. This tables was designed to be inclusive, so sources of questionable quality are included, according to the authors. For instance, 134 sources have net numbers of counts in the 0.5-8.0 keV band that are consistent with 0 at the 90% confidence level. These sources are only detected in a single band and are presumably either very hard or very soft, detected in single observations because they were transients, or detected in stacked observations with wvdecomp at marginal significance. The authors have chosen to include them because they passed the test based on Poisson statistics from Weisskopf et al. (2007, ApJ, 657, 1026). The observations which were used to generate the source list herein tabulated are listed in Table 1 of the reference paper. This HEASARC table GALCENCXO supercedes and replaces the previous HEASARC tables CHANGALCEN and CHANC150PC, which were based on Muno et al. (2003, ApJ, 589, 225) and Muno et al. (2006, ApJS, 165, 173), respectively. This table was created by the HEASARC in March 2009 based on the machine-readable versions of Table 2, 3 and 4 from the paper which were obtained from the electronic ApJ website. The information on short-term variability given in Table 5 of the reference paper was not included in this HEASARC table, notice. This is a service provided by NASA HEASARC .

This table contains the main X-ray source catalog for the Chandra monitoring observations of the 16.5-Mpc distant elliptical galaxy, NGC 4649. The galaxy has been observed with Chandra ACIS-S3 in six separate pointings, reaching a total exposure of 299 ks. There are 501 X-ray sources detected in the 0.3-8.0 keV band in the merged observation or in one of the six individual observations; 399 sources are located within the D₂₅ ellipse. The observed 0.3-8.0 keV luminosities of these 501 sources range from 9.3 x 10³⁶ erg s^-1 to 5.4 x 10³⁹ erg s^-1. The 90% detection completeness limit within the D₂₅ ellipse is 5.5 x 10³⁷ erg s^-1. Based on the surface density of background active galactic nuclei (AGNs) and the detection completeness, we expect ~ 45 background AGNs among the catalog sources (~ 15 within the D₂₅ ellipse). There are nine sources with luminosities greater than 10³⁹ erg s^-1, which are candidates for ultraluminous X-ray sources. The nuclear source of NGC 4649 is a low-luminosity AGN, with an intrinsic 2.0-8.0 keV X-ray luminosity of 1.5 x 10³⁸ erg s^-1. The X-ray colors suggest that the majority of the catalog sources are low-mass X-ray binaries (LMXBs). The authors find that 164 of the 501 X-ray sources show long-term variability, indicating that they are accreting compact objects, and discover four transient candidates and another four potential transients. They also identify 173 X-ray sources (141 within the D₂₅ ellipse) that are associated with globular clusters (GCs) based on Hubble Space Telescope and ground-based data; these LMXBs tend to be hosted by red GCs. Although NGC 4649 has a much larger population of X-ray sources than the structurally similar early-type galaxies, NGC 3379 and NGC 4278, the X-ray source properties are comparable in all three systems. This HEASARC table contains the main Chandra source catalog of the basic properties of the 501 X-ray detected sources (Table 3 in the reference paper which includes both sources detected in the merged X-ray image as well as a number only detected in the individual observations), and also the information on source counts, hardness ratios and soft and hard X-ray colors in the merged observation for the same 501 X-ray detected sources (Table 4 in the reference paper). It does not contain the information on source counts, hardness ratios and soft and hard X-ray colors for these same sources in the six individual observations that were contained in Tables 5 - 10 of the reference paper. This table was created by the HEASARC in March 2013 based on the electronic version of Tables 3 and 4 from the reference paper which were obtained from the ApJS website.. This is a service provided by NASA HEASARC .

This table contains some of the results from a Chandra ACIS observation of the stellar populations in and around the M17 H II region. The field reveals 886 sources (listed in the present table) with observed X-ray luminosities (uncorrected for absorption) between ~ 29.3 erg s^-1 < log L_X < 32.8 erg s^-1, 771 of which have stellar counterparts in infrared images. Spectral analysis results for the 598 brightest X-ray sources which have photometric significance of 2.0 or greater) are also given herein. For 546 of the X-ray sources, the fits used the "wabs(apec)" thermal plasma model in XSPEC assuming scaled 0.3 times solar photospheric abundances, while for the other 52 X-ray sources for which either the thermal model poorly described the data or required nonphysical parameters and the X-ray source was not identified with a known stellar counterpart, the fits used the "wabs(powerlaw)" model in XSPEC. In addition to the comprehensive tabulation of X-ray source properties, several other results were presented in the reference paper: 1. The X-ray luminosity function is calibrated to that of the Orion Nebula Cluster population to infer a total population of roughly 8000-10,000 stars in M17, one-third lying in the central NGC 6618 cluster. 2. About 40% of the ACIS sources are heavily obscured with A_V > 10 mag. Some are concentrated around well-studied star-forming regions -- IRS 5/UC1, the Kleinmann-Wright Object, and M17-North -- but most are distributed across the field. As previously shown, star formation appears to be widely distributed in the molecular clouds. X-ray emission is detected from 64 of the hundreds of Class I protostar candidates that can be identified by near- and mid-infrared colors. These constitute the most likely protostar candidates known in M17. 3. The spatial distribution of X-ray stars is complex: in addition to the central NGC 6618 cluster and well-known embedded groups, we find a new embedded cluster (designated M17-X), a 2 pc long arc of young stars along the southwest edge of the M17 H II region, and 0.1 pc substructure within various populations. These structures may indicate that the populations are dynamically young. 4. All (14/14) of the known O stars but only about half (19/34) of the known B0-B3 stars in the M17 field are detected. These stars exhibit the long-reported correlation between X-ray and bolometric luminosities of L_X ~ 10^-7 L_bol. While many O and early-B stars show the soft X-ray emission expected from microshocks in their winds or moderately hard emission that could be caused by magnetically channeled wind shocks, six of these stars exhibit very hard thermal plasma components (kT > 4 keV) that may be due to colliding wind binaries. More than 100 candidate new OB stars are found, including 28 X-ray detected intermediate- and high-mass protostar candidates with infrared excesses. 5. Only a small fraction (perhaps 10%) of X-ray selected high- and intermediate-mass stars exhibit K-band-emitting protoplanetary disks, providing further evidence that inner disks evolve very rapidly around more massive stars. This table was created by the HEASARC in December 2007 based on electronic versions of Tables 1, 2, 3, 4 and 5 of the reference paper which were obtained from the electronic ApJ web site. This is a service provided by NASA HEASARC .

This table lists some of the properties of the discrete X-ray sources detected in the authors' monitoring program of the globular cluster (GC)-rich elliptical galaxy, NGC 4278, observed with Chandra ACIS-S in six separate pointings, resulting in a co-added exposure of 458 ks. From this deep observation, 236 sources have been detected within the region overlapped by all observations, 180 of which lie within the D₂₅ ellipse angular diameter of the galaxy. These 236 sources range in X-ray luminosity L_X from 3.5 x 10³⁶ erg s^-1 (with 3-sigma upper limit <= 1 x 10³⁷ erg s^-1) to ~2 x 10⁴⁰ erg s^-1, including the central nuclear source which has been classified as a LINER. From optical data, 39 X-ray sources have been determined to be coincident with a GC, these sources tend to have high X-ray luminosity, with 10 of these sources exhibiting L_X > 1 x 10³⁸ erg s^-1. From X-ray source photometry, it has been determined that the majority of the 236 point sources that have well-constrained colors have values that are consistent with typical low-mass X-ray binary spectra, with 29 of the sources expected to be background objects from the log N-log S relation. There are 103 sources in this population that exhibit long-term variability, indicating that they are accreting compact objects. Three of these sources have been identified as transient candidates, with a further three possible transients. Spectral variations have also been identified in the majority of the source population, where a diverse range of variability has been identified, indicating that there are many different source classes located within this galaxy. This HEASARC table contains the master source list (Table 3 of the reference paper) and the X-ray properties of the sources in the co-added observations (Table 4 of the reference paper), but not the X-ray properties of the sources in the 6 individual observations (Tables 5-10 of the reference paper). The details of the six individual pointings used in this study, e.g., the Chandra ObsIDs, dates, exposure times and cleaned exposure times, are given in Table 1 of the reference paper, and repeated here:

 Obs. No.OBSID Date Exposure (s) Cleaned Exposure (s) 1 4741 2005 Feb 3 37462.0 37264.5 2 7077 2006 Mar 16 110303.8 107736.7 3 7078 2006 Jul 25 51433.2 48076.2 4 7079 2006 Oct 24 105071.7 102504.6 5 7081 2007 Feb 20 110724.0 107564.5 6 7080 2007 Apr 20 55824.8 54837.5 Total Co-added 470819.5 457984.0 

Notes. The pointing OBSID 7181 was taken before OBSID 7080, so to maintain the time sequence of the exposures these observation numbers have been labeled as above in the reference paper. The details of the energy bands and X-ray colors used in this study are given in Table 2 of the reference paper, and repeated here:

 Band/Color Energy Range/Definition Broad (B) 0.3-8 keV Soft (S) 0.3-2.5 keV Hard (H) 2.5-8 keV Soft 1 (S1) 0.3-0.9 keV Soft 2 (S2) 0.9-2.5 keV Conventional broad (Bc) 0.5-8 keV Conventional soft (Sc) 0.5-2 keV Conventional hard (Hc) 2-8 keV Hardness ratio HR (Hc-Sc)/(Hc+Sc) X-ray color C21 -log(S2) + log(S1) = log(S1/S2) X-ray color C32 -log(H) + log(S2) = log(S2/H) 

This table was created by the HEASARC in April 2009 based on machine-readable versions of Tables 3 and 4 from the reference paper which were obtained from the ApJ web site. This is a service provided by NASA HEASARC .

A Chandra X-Ray Observatory ACIS-S imaging observation is used to study the population of X-ray sources in the nearby (3.6 Mpc) Sab galaxy M 81 (NGC 3031). A total of 177 sources are detected, with 124 located within the D_25 isophote to a limiting X-ray luminosity of ~ 3 x 10³⁶ erg/s. Source positions, count rates, luminosities in the 0.3 - 8.0 keV band, limiting optical magnitudes, and potential counterpart identifications are tabulated. Spectral and timing analysis of the 36 brightest sources are reported, including the low-luminosity active galactic nucleus, SN 1993J, and the Einstein-discovered ultraluminous X-ray source X6. The primary X-ray data set is a 49926 s observation of M81 obtained on 2000 May 7 with the Chandra Advanced CCD Imaging Spectrometer (ACIS) spectroscopy array operating in imaging mode. The X-ray data were reprocessed by the Chandra X-ray Center (CXC) on 2001 January 4. These reprocessed data were used in this work. There are no significant differences between the reprocessed data and the originally distributed data analyzed by Tennant et al. (2001ApJ...549L..43T). The observation was taken in faint timed exposure mode at 3.241 s/frame at a focal plane temperature of -120 C. Standard CXC processing has applied aspect corrections and compensated for spacecraft dither. The primary target, SN 1993J, was located near the nominal aimpoint on the back-illuminated (BI) device S3. The nucleus of M81 lies 2.79' from SN 1993J toward the center of S3 in this observation. Accurate positions of these two objects and two G0 stars located on device S2 were used to identify any offset and to determine absolute locations of the remaining Chandra sources as well as objects in other X-ray images and those obtained at other wavelengths. No offset correction was applied to the Chandra X-ray positions. This table was created by the HEASARC in March 2007 based on the CDS table J/ApJS/144/213, files table2.dat and table3.dat. This is a service provided by NASA HEASARC .

This table contains the source table from an analysis of 15 Chandra ACIS observations of the nearby spiral galaxy M81 taken over the course of six weeks in 2005 May-July. Each observation reaches a sensitivity of ~10³⁷ erg s^-1. With these observations and one previous deeper Chandra observation (the properties of which are described in Table 1 and Section 2 of the reference paper), the authors have compiled a master source list of 265 point sources, extracted and fitted their spectra, and differentiated basic populations of sources through their colors. They also carried out variability analyses of individual point sources and of X-ray luminosity functions (XLFs) in multiple regions of M 81 on timescales of days, months, and years. They find that, despite measuring significant variability in a considerable fraction of sources, snapshot observations provide a consistent determination of the XLF of M81. They also fit the XLFs for multiple regions of M81 and, using common parametrization, compare these luminosity functions to those of two other spiral galaxies, M31 and the Milky Way. This table contains the 265 point sources at or above the 99.9% probability level of being real according to AE's PROB_NO_SOURCE statistic (the "master" source list), and 11 additional "borderline" sources which have 99.0-99.9% probability of being real according to AE's PROB_NO_SOURCE statistic, for a total of 276 sources whose properties were described in Tables 3 and 4 of the reference paper. The 265 "master" sources have source numbers from 1 to 265 while the 11 "borderline" sources have source numbers beginning with 'B', e.g., they have source numbers 'B1' to 'B11'. Note that only coordinates are listed for 3 sources in the master source list (source numbers 234, 241 and 262) and 2 sources in the borderline source list (B8 and B9) because they were only in the field of view (on chip) of one observation (ObsID 735). Six additional sources near the center of M81 which were found using maximum likelihood image reconstruction are not included in either the master or borderline source lists contained herein but their positions are listed in table 2 of the reference paper. This table was created by the HEASARC in August 2011 based on electronic versions of Tables 3 and 4 from the reference paper which were obtained from the ApJ web site. Some of the values for the name parameter in the HEASARC's implementation of this table were corrected in April 2018. This is a service provided by NASA HEASARC .