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NGC 6357 Chandra X-Ray Point Source Catalog
This contains some of the results from the first high spatial resolution X-ray study of the massive star-forming region NGC 6357, which were obtained in a 38 ks Chandra/ACIS observation. Inside the brightest constituent of this large H II region complex is the massive open cluster Pismis 24. It contains two of the brightest and bluest stars known, yet remains poorly studied; only a handful of optically bright stellar members have been identified. The authors have investigated the cluster extent and initial mass function and detected ~800 X-ray sources with a limiting sensitivity of ~ 10<sup>30</sup> erg s<sup>-1</sup>: this provides the first reliable probe of the rich intermediate-mass and low-mass population of this massive cluster, increasing the number of known members from optical studies by a factor of ~ 50. The high-luminosity end (log L[2-8 keV] >= 30.3 erg s<sup>-1</sup>) of the observed X-ray luminosity function in NGC 6357 is clearly consistent with a power-law relation as seen in the Orion Nebula Cluster and Cepheus B, yielding the first estimate of NGC 6357's total cluster population, a few times the known Orion population. The long-standing L<sub>X</sub> ~ 10<sup>-7</sup> L<sub>bol</sub> correlation for O stars is confirmed. Twenty-four candidate O stars and one possible new obscured massive YSO or Wolf-Rayet star are presented. Many cluster members are estimated to be intermediate-mass stars from available infrared photometry (assuming an age of ~ 1 Myr), but only a few exhibit K-band excess. The authors report the first detection of X-ray emission from an evaporating gaseous globule at the tip of a molecular pillar; this source is likely a B0-B2 protostar. NGC 6357 was observed on 2004 July 9 with the Imaging Array of the Advanced CCD Imaging Spectrometer (ACIS-I) on board Chandra. Four front-illuminated (FI) CCDs form the ACIS-I, which covers a field of view (FOV) of ~ 17 by 17 arcminutes. The observation was made in the standard Timed Exposure, Very Faint mode, with 3.2 s integration time and 5 pixel by 5 pixel event islands. The total exposure time was 38 ks and the satellite roll angle was 289 degrees. The aim point was centered on the O3 If star Pis 24-1, the heart of the OB association Pismis 24. The Chandra observation ID is 4477. Data reduction started with filtering the Level 1 event list processed by the Chandra X-ray Center pipeline to recover an improved Level 2 event list. To improve absolute astrometry, X-ray positions of ACIS-I sources were obtained by running the wavdetect wavelet-based source detection algorithm within the Chandra Interactive Analysis of Observations (CIAO) package on the original Level 2 event list, using only the central 8 by 8 arcminutes of the field. The resulting X-ray sources were matched to the 2MASS point source catalog. The authors calculated the position offsets between 277 X-ray sources and their NIR counterparts and applied an offset of +0.02" in right ascension (R.A.) and -0.33" in declination to the X-ray coordinates. From an initial list of 910 potential X-ray sources, the authors rejected sources with a P<sub>B</sub> > 1% likelihood of being a background fluctuation. The trimmed source list includes 779 sources, with full-band (0.5 - 8.0 keV) net (background-subtracted) counts ranging from 1.7 to 1837 counts. The 779 valid sources were purposely divided by the authors into two lists: the 665 sources with P<sub>B</sub> < 0.1% make up the primary source list of highly reliable sources (Table 1 in the reference paper; sources with source_type = 'M' in this table), and the remaining 114 sources with P<sub>B</sub> >= 0.1% likelihood of being spurious background fluctuations were listed as tentative sources in Table 2 of the reference paper (source_type = 'T' in this table). The authors believe that most of these tentative sources are likely real detections. This table was created by the HEASARC in October 2007 based on the merger of the electronic versions of Tables 1 (Main Source Catalog) and 2 (Tentative Sources which were obtained from the ApJ website. To help distinguish from which original table entries in this Browse table come from, the HEASARC has created a parameter called source_type which is set to 'M' for sources from Table 1 and to 'T' for sources from Table 2. This is a service provided by NASA HEASARC .
ROSAT HRI Catalog of LMC X-Ray Sources (Sasaki et al.)
All 543 pointed observations of the ROSAT High Resolution Imager (HRI) with exposure times higher than 50 seconds, and performed between 1990 and 1998 in a field of 10 by 10 degrees covering the Large Magellanic Cloud were analyzed, and a source catalogue was produced that contains 397 X-ray sources whose properties have been measured with the HRI. The list was cross-correlated with the ROSAT Position Sensitive Proportional Counter (PSPC) LMC source catalogue of Haberl and Pietsch (1999, A&AS, 139, 277; the HEASARC database LMCROSXRAY) in order to obtain the (PSPC) hardness ratios for the X-ray sources detected by both instruments. 138 HRI sources are contained in the PSPC Catalogue, while 259 sources are new detections. The spatial resolution of the HRI being better than that of the PSPC, source positions could be determined with errors smaller than 15 arcsec which are dominated by systematic errors. After cross-correlating the source catalogue with the SIMBAD database and the Tycho Catalogue, 94 HRI sources were identified with known objects based on their positional coincidences and X-ray properties. Whenever more accurate coordinates were given in catalogues or the literature, the X-ray coordinates were corrected and the systematic error of the X-ray position was reduced. For other sources observed simultaneously with an identified source, the positional coordinates were also improved. In total, the X-ray positions of 254 sources were newly determined. The sources identified in this study include 39 foreground stars, 24 supernova remnants (SNR), 5 supersoft sources, 9 X-ray binaries, and 9 active galactic nuclei (AGN) well-known from the literature. Another 8 sources were identified with known candidates for these source classes. An additional 21 HRI sources were suggested by the authors as candidates for SNR, X-ray binaries in the LMC, or background AGN, because of their spatial extents, hardness ratios, X-ray to optical flux ratios, or flux variability. This database was created at the HEASARC in June 2000 based on the ADC/<a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+AS/143/391">CDS Catalog J/A+AS/143/391</a>, and is derived from Table 4 of the reference. This is a service provided by NASA HEASARC .
Early-Type Galaxies Chandra X-Ray Point Source Catalog
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<sub>X</sub>). The composite XLF is well fitted by a power law with a break at (2.21 [+0.65,-0.56]) x 10<sup>38</sup> erg s<sup>-1</sup> 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<sub>X</sub> XLF slope does not correlate with age, but may correlate with [Alpha/Fe]. Considering only LMXBs with L<sub>X</sub> > 10<sup>37</sup> erg s<sup>-1</sup>, 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<sub>GC</sub><sup>Alpha</sup> Z<sub>Fe</sub><sup>Gamma</sup> 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<sub>X</sub> > 10<sup>37</sup> erg s<sup>-1</sup> 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<sub>L</sub> and the duty cycle is F<sub>d</sub>, their results imply ~ 1.5(Tau<sub>L</sub>/10<sup>8</sup> yr)<sup>-1</sup> F<sub>d</sub><sup>-1</sup> LMXBs are formed per gigayear per GC, and they place an upper limit of one active LMXB in the field per 3.4 x 10<sup>9</sup> solar luminosities of V-band luminosity. This table contains 1194 X-ray point sources that were detected within the B-band 25th magnitude ellipse D<sub>25</sub> (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 D<sub>25</sub> 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 .
Swift-BAT 157-Month All-Sky Hard X-Ray Survey
This catalog includes the hard X-ray sources detected in the first 157 months of observations with the Burst Alert Telescope (BAT) coded-mask imager on board the Swift observatory. The results of the 157 months survey catalog has been obtained using data from February 2007 to December 2017 and provide a uniform hard X-ray all-sky survey with a sensitivity of 8.40 x 10<sup>-12</sup> erg/s/cm<sup>2</sup> over 90% of the sky and 7.24 x 10<sup>-12</sup> erg/s/cm<sup>2</sup> over 50% of the sky in the 14-195 keV band. The exposure time in all sky ranges from ~ 15 Ms to ~ 35 Ms, where ~ 50% of the sky achieves an exposure time of ~ 22.8 Ms. The 157 months survey provides 1891 hard X-ray sources in the 14-195 keV band above the 4.8 sigma significance level, where 259 are new detections from the 105-month catalog of which 54 are previously known source in X-ray. The sources identification is mostly from NED and SIMBAD and the 157-month catalog reports for positive identification the counterpart R.A. and Dec and the alternative name. The sources are classified in 17 different classes as follows: <pre> Class Source Type Number of Sources 0 Unknown 221 1 Galactic 4 2 Galaxy 16 3 Galaxy Cluster 26 4 Seyfert I 446 5 Seyfert II 464 6 Other AGN 130 7 Beamed AGN (Blazar/FSRQ) 192 8 LINER 7 9 Cataclysmic Variable Star (CV) 81 10 Pulsar 27 11 Supernova Remnant (SNR) 7 12 Star 26 13 High Mass X-ray Binary (HMXB) 108 14 Low Mass X-ray Binary (LMXB) 118 15 Other X-ray Binary (XRB) 17 16 Tidal Disruption Event 1 Total 1891 </pre> The data reduction, analysis, and catalog generation of the Swift-BAT are conducted following the same procedures of the previous catalog survey (Tueller+ 2010, J/ApJS/1167/186, Baumgartner+ 2013, J/ApJS/207/19). The BAT survey data are collected into arrays (Detector Plane Histograms, DPHs) where the data are binned in ~ 300 s time interval and in 8 energy band channels (14-20, 20-24, 24-35, 35-50, 50-75, 75-100, 100- 197 150, and 150-195 keV) and 1 energy total band (14-195 keV). Three different mosaic images are created from the DPH dividing the sky in 6 regions. The first set has images created in 8 energy bands to span a contiguous time interval (snapshot). The second set has images co-adding data on a time period of a month. The third set is created in 8 energy bands by Crab-weighting the monthly images in each of the energy band with the following weights (Baumgartner+ 2013, J/ApJS/207/19): 27.000, 35.260, 22.700, 29.444, 21.272, 16.062, 8.449, 2.630. The benchmark Crab spectrum adopted is F(E) = 10.17E−2.15 photon cm2 s keV. The source detection algorithm uses the Crab-weighted mosaic images. For each source detected lightcurves and spectra are derived. The lightcurves are obtained from the snapshot images, the mosaic monthly images and the Crab-weighted mosaic images. The spectra are obtained from an additional set of mosaic images by adding all the snapshots for the 157 months period in 8-bands. All the analyses use HEASoft tools version 6.23, and the most recent BAT calibration database (updated on Oct. 3, 2017). Data products are generated for each source detected and these are: three different lightcurves in FITS format obtained from the snapshot, monthly and Crab-weighted monthly mosaic images and the equivalent plots as GIF images; an 8-channel average spectrum in FITS obtained using all 157 months; and a GIF file showing the spectrum with the fit to the best parameter of the power-law model. The snapshot lightcurves report rates for the 8-energy band, the monthly and Crab-weighted monthly mosaic lightcurves reports rated for the 8-energy band and the total band 14-195 keV. This table was ingested by the HEASARC in February 2025 based upon the published 157-month catalog. The catalog is also available at <a href="https://swift.gsfc.nasa.gov/results/bs157mon/">https://swift.gsfc.nasa.gov/results/bs157mon/</a>. This is a service provided by NASA HEASARC .
NGC 2808 Chandra X-Ray Point Source Catalog
This table contains the sources detected in a Chandra X-ray observation of the Galactic globular cluster NGC 2808, as well as the corresponding XMM-Newton data for those sources which have XMM-Newton X-ray counterparts. Using new Chandra X-ray observations and existing XMM-Newton X-ray and Hubble Space Telescope far-ultraviolet observations, the authors aim to detect and identify the faint X-ray sources belonging to NGC 2808 in order to understand their role in the evolution of globular clusters. The authors classify the X-ray sources associated with the cluster by analysing their colors and variability. Previous observations with XMM-Newton and far-ultraviolet observations with Hubble are re-investigated to help identify the Chandra sources associated with the cluster. The authors compare their results to population synthesis models and observations of other Galactic globular clusters. NGC 2808 was observed with the Chandra X-ray Observatory Advanced CCD Imaging Spectrometer-Imager (ACIS-I) on 2007 June 19-21 (28 months after the XMM-Newton observation referred to the reference paper) for two distinct exposures of 46 and 11 kiloseconds. The authors detect 113 sources, of which 16 fall inside the half-mass radius of NGC 2808 and are concentrated towards the cluster core. This table was created by the HEASARC in February 2009 based on the electronic version of Table 1 from the paper which was obtained from the CDS (their catalog J/A+A/490/641 file table1.dat). This is a service provided by NASA HEASARC .
Selected Hickson Compact Groups Chandra X-Ray Point Source Catalog
This table contains the Chandra X-ray point source catalogs for 9 Hickson Compact Groups (HCGs, 37 galaxies) at distances of 34 to 89 Mpc. The authors perform detailed X-ray point source detection and photometry and interpret the point source population by means of simulated hardness ratios. They thus estimate X-ray luminosities (L<sub>X</sub>) for all sources, most of which are too weak for reliable spectral fitting. For all sources, they provide counts, count rates, power-law indices (Gamma), hardness ratios, and L<sub>X</sub>, in the full (0.5-8.0 keV), soft (0.5-2.0 keV) and hard (2-8 keV) bands. In their paper, the authors use optical emission-line ratios from the literature to re-classify 24 galaxies as star-forming, accreting onto a supermassive black hole (AGNs), transition objects, or low-ionization nuclear emission regions. Two-thirds of their galaxies have nuclear X-ray sources with Swift/UVOT counterparts. Two nuclei have full-band X-ray luminosities >= 10<sup>42</sup> erg s<sup>-1</sup>, are strong multi-wavelength AGNs, and follow the known alpha<sub>OX</sub> - nu L_nu(near-UV)_ correlation for strong AGNs. Otherwise, most nuclei are X-ray faint, consistent with either a low-luminosity AGN or a nuclear X-ray binary population, and fall into the 'non-AGN' locus in alpha<sub>OX</sub> - nu L_nu(near-UV)_ space, which also hosts other normal galaxies. Each group was observed at the aim point of the back-illuminated S3 CCD of Chandra's Advanced CCD Imaging Spectrometer (ACIS), with the exception of HCG 90, which was observed with the ACIS-I array. The details of the 9 Chandra observations analyzed herein are given in Table 1 of the reference paper. The full details of the X-ray analysis and point source detection procedures are given in Section 3 of the reference paper. This table was created by the HEASARC in June 2014 based on electronic versions of Tables 2 and 3 from the reference paper which were obtained from the ApJS 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 .
Rho Ophiuchi SFR Chandra X-Ray Point Source Catalog
This catalog of X-ray sources represents some of the results of a systematic study of X-ray flares from low-mass young stellar objects, using two deep exposure Chandra observations of the main region of the rho Ophiuchi star-forming cloud. From 195 X-ray sources, including class I-III pre-main sequence sources and some young brown dwarfs, a total of 71 X-ray flares were detected. The Chandra X-ray Observatory (Weisskopf et al., 2002PASP..114....1W) observed the central region of rho Oph twice with a deep exposure of the ACIS-I array, consisting of four abutted X-ray CCDs. The first observation (here and after, obs. BF) covered the south-east 17.4' x 17.4' area, including cores B, C, E, and F, while the second observation (obs. A) covered the north-west area centered on core A (Loren et al., 1990ApJ...365..269L). This table contains data and the results of spectral and timing analyses on the 195 sources detected in the two rho Oph fields, 9 of which were detected in both fields and are therefore listed twice (A-61=BF-2, A-64=BF-4, A-65=BF-5, A-69=BF-7, A-75=BF-11, A-77=BF-15, A-78=BF-16, A-79=BF-17, and A-81 = BF-19). Sources which flared have multiple entries, with one entry (typically, but not always) listing the properties of the quiescent emission, and additional entries for individual flares which were analyzed separately. For the very faint sources for which the temperatures obtained from X-ray spectral analyses were not constrained, there are typically two entries in this table per source, one of which gives the results of a spectral analysis in which the temperature was fixed at 1 keV (11.6 MK) and the other in which the temperature was instead fixed at 5 keV (58 MK). Thus, there are more entries (306) in this HEASARC table than the number (195) of detected rho Oph X-ray sources. This table was created by the HEASARC in February 2007 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/PASJ/55/653">CDS Catalog J/PASJ/55/653</a> files table2.dat and table3.dat. This is a service provided by NASA HEASARC .
Ultraluminous X-Ray Sources in External Galaxies Catalog
This table is a catalog of ultraluminous X-ray sources (ULXs) in external galaxies, where ULXs have been defined as compact, off-nuclear X-ray sources with X-ray luminosities in the range of 10<sup>39</sup> - 10<sup>41</sup> erg/s. The aim of this catalog is to provide easy access to the properties of ULXs, their possible counterparts at other wavelengths (optical, IR, and radio), and the properties of their host galaxies. The catalog contains 229 ULXs found in 85 galaxies which had been reported in the astronomy literature as of April 2004. Most ULXs are stellar-mass-black hole X-ray binaries, but it cannot be excluded that some ULXs might be intermediate-mass black holes. A small fraction of the candidate ULXs might be background Active Galactic Nuclei (AGN) or Supernova Remnants (SNRs). ULXs with luminosity above 10<sup>40</sup> erg/s are found in both starburst galaxies and in the halos of early-type galaxies. Some notes on individual galaxies and/or ULXs in this catalog can be found in the file <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/429/1125/notes.dat">https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/429/1125/notes.dat</a> which is available at the CDS. This table was created by the HEASARC in January 2005, based on CDS tables J/A+A/429/1125/table1a.dat and table1b.dat. It was updated in September 2012 to correct an error in the declination signs of the NGC 253 objects. This is a service provided by NASA HEASARC .
NGC 6530 Chandra X-Ray Point Source Catalog
In a deep 60 ks Chandra ACIS-I X-ray observation of the very young (~ 1.5 - 2.0 Myr) cluster NGC 6530 on 2001 Jun 18-19, the authors have detected 884 X-ray point sources and argue that a very large fraction of them (90%-95%) must be pre-main-sequence (PMS) cluster members, mostly low-mass stars. This is a significant enlargement of the known NGC 6530 stellar population with respect to previous optical studies, including H-alpha surveys. They identify 220 X-ray sources with catalogued stars down to V = 17, while most unidentified sources have fainter counterparts. Moreover, they find an infrared counterpart in the 2MASS (CDS. No. <II/246>) Catalog for 731 X-ray sources. The optically identified cluster X-ray sources are found in a band in the H-R diagram above the main sequence, in the locus of 0.5 - 1.5 Myr PMS stars, with masses down to 0.5 - 1.5 solar masses (M_sun). The pointing direction for the Chandra observation was the NGC 6530 cluster center at RA = 18^h 04^m 24.38^s, Dec = -24^o 21' 05.8" (J2000.0). The PWDetect algorithm found 884 X-ray point sources in the ACIS-I image above a detection significance threshold chosen to ensure only 1 spurious detection on the average. The Sung et al. (2000, AJ, 120, 333; <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/120/333">CDS Cat. <J/AJ/120/333></a>) = SCB Catalog of optical objects against which the X-ray point source list was compared doed not cover the easternmost 2.25' of the ACIS FOV (RAs later than 18^h 04^m 52^s), notice, which comprises about 13% of the ACIS FOV. There are 46 detected X-ray sources (5.2% of the total) in the area not covered by the SCB Catalog. A matching distance of 4 times the X-ray error radius or 2.0" (whichever is greater) was used to identify optical counterparts to the X-ray sources, after a systematic shift between the X-ray and optical positions of -0.4" and 1.84" in RA and declination, respectively, was applied. The authors estimate that as many as 28 of their 220 optical identifications may be spurious, preferentially those in the outer parts of the FOV where the positional uncertainties are larger. There are 8792 'good' 2MASS sources in the ACIS FOV. A matching distance of 4 times the X-ray error radius or 1.5" (whichever is greater) was used to identify 2MASS counterparts to the X-ray sources, after systematic corrections of 0.3" and 1.75" in RA and declination, respectively, were applied to the 'raw' X-ray positions. There are 13 cases where there are two possible IR counterparts to a single X-ray source, and 2 cases where there are three possible IR Counterparts to a single X-ray source. (Notice that, in such cases, this table contains multiple entries, one for each counterpart, and hence there are 901 entries compared to 884 X-ray sources.) The authors conclude that the plausible number of spurious X-ray-2MASS identifications is between 30 and 50. Overall, there remain 146 X-ray sources with no optical or IR identification. This table was created by the HEASARC in December 2006 based on CDS table J/ApJ/608/781, the file table1.dat. This is a service provided by NASA HEASARC .
LkH-alpha 101 Star Formation Region Chandra X-Ray Point Source Catalog
This table contains some of the results from a multi-wavelength study of a partially embedded region of star formation centered on the Herbig Be star LkH-alpha 101. Using two 40 ks Chandra observations, The authors have detected 213 X-ray sources in the ~ 17' x 17' ACIS-I field. They combine the X-ray data with Two Micron All Sky Survey (2MASS) near-IR observations and Spitzer Space Telescope (SST) IRAC and MIPS 24-micron observations to obtain a complete picture of the cluster. A total of 158 of the X-ray sources have infrared counterparts. Of these, the authors find nine protostars, 48 Class II objects, five transition objects, and 72 Class III objects. From the Spitzer data, they identify an additional 10 protostars, 53 Class II objects, and four transition disk candidates which are not detected by Chandra. (These objects are not included in this HEASARC table which contains the multi-wavelength data for only the 213 detected X-ray sources). The authors obtained optical spectra of a sample of both X-ray-detected and non-X-ray-detected objects. Combining the X-ray, Spitzer, and spectral data, they obtain independent estimates of cluster distance and the total cluster size - excluding protostars. The authors obtain consistent distance estimates of 510 (+100,-40) pc and a total cluster size of 255 (+50,-25) stars. They find the Class II:III ratio is about 5:7 with some evidence that the Class III sources are spatially more dispersed. The cluster appears very young with three sites of active star formation and a median age of about 1 Myr. The field was observed by Chandra on 2005 March 6 starting at 17:16 UT for 40.2 ks of total time and 39.6 ks of the so-called good time (Chandra ObsID 5429). It was observed again on 2005 March 8 starting at 17:43 UT for essentially the same duration (Chandra ObsID 5428). The ACIS was used in the nominal imaging array (chips I0-I3) which provides a field of view of approximately 17' x 17'. The aimpoint was at RA, Dec = 04:30:14.4, +35:16:22.2 (J2000.0) with a roll angle of 281 degrees. In addition, the S2 and S3 chips were active; however, the analysis of these data is not presented here. For purposes of point-source detection, the data from the two observations were merged into a single event list following established CIAO procedures to create a merged event list. To identify point sources, photons with energies below 300 eV and above 8.0 keV were filtered out from this merged event list. This excluded energies which generally lack a stellar contribution. By filtering the data as described, contributions from hard, non-stellar sources such as X-ray binaries and active galactic nuclei (AGNs) are attenuated, as is noise. A monochromatic exposure map was generated in the standard way using an energy of 1.49 keV which is a reasonable match to the expected peak energy of the stellar sources and the Chandra mirror transmission. The CIAO tool WavDetect was then run on a series of flux-corrected images binned by 1, 2, and 4 pixels. The output source lists were combined and this resulted in the detection of 231 sources. The authors defined false detections as any sources with < 4 net counts or any sources more than 5' off-axis with < 7 net counts. By this definition, 18 of the 231 detections were rejected as false detections. A post facto check confirmed that none of these (spurious) sources had an infrared counterpart. This table was created by the HEASARC in July 2010 based on the versions of Tables 1, 2, 3, 7 and 9 from the paper which were obtained from the electronic ApJ web site. This is a service provided by NASA HEASARC .
NGC 752 XMM-Newton X-Ray Point Source Catalog
This table provides a list of X-ray sources detected in a ~50 ks XMM-Newton X-ray observation of the open cluster NGC 752. For the sources with 2MASS counterparts, the values of their magnitudes in the J, H and K bands are also given. Additionally, for the sources with a Chandra counterpart (within a search radius of 5 arcsec), the values of their Chandra source number (as given in the related Browse table NGC752CXO) are also given. Very little is known about the evolution of stellar activity between the ages of the Hyades (0.8 Gyr) and the Sun (4.6 Gyr). To gain information on the typical level of coronal activity at a star's intermediate age, the authors have studied the X-ray emission from stars in the 1.9 Gyr-old open cluster NGC 752. They analyzed a ~ 140 ks Chandra observation of NGC 752 and a ~50 ks XMM-Newton observation of the same cluster. They detected 262 X-ray sources in the Chandra data and 145 sources in the XMM-Newton observation. Around 90% of the catalogued cluster members within Chandra's field of view are detected in the X-ray observation. The X-ray luminosity of all observed cluster members (28 stars) and of 11 cluster member candidates was derived. These data indicate that, at an age of 1.9 Gyr, the typical X-ray luminosity L<sub>x</sub> of the cluster members with masses of 0.8 to 1.2 solar masses is 1.3 x 10<sup>28</sup> erg s<sup>-1</sup>, which is approximately a factor of 6 times less intense than that observed in the younger Hyades. Given that L<sub>x</sub> is proportional to the square of a star's rotational rate, the median L<sub>x</sub> of NGC 752 is consistent, for t >= 1 Gyr, with a decaying rate in rotational velocities v<sub>rot</sub> ~ t<sup>-alpha</sup> with alpha ~ 0.75, steeper than the Skumanich relation (alpha ~ 0.5) and significantly steeper than that observed between the Pleiades and the Hyades (where alpha <0.3), suggesting that a change in the rotational regimes of the stellar interiors is taking place at an age of ~ 1 Gyr. NGC 752 was observed for 49 ks by the XMM-Newton EPIC camera on February 5, 2003 starting at 23:29:25 UT, and the nominal pointing was towards J2000.0 RA and Declination of (01:57:38, +37:47:60), thus the XMM-Newton field-of-view (FOV) includes the Chandra FOV. For the source detection, the authors used the PWXDETECT code developed at Palermo Observatory and derived from the analogous Chandra PWDETECT code based on wavelet transform analysis. This allows the three EPIC exposures (PN, MOS1 and MOS2) to be combined in order to gain a deeper sensitivity with respect to the source detection based on single images. There were 145 point sources detected in the energy band 0.5 - 2.0 keV. An extended source (not listed in this present table), very likely a galaxy cluster, is also visible in the EPIC data. The authors searched for 2MASS counterparts to the XMM-Newton sources using a search radius of 5 arcsec and found a counterpart for 38 sources. As for the Chandra data, all sources with a visible counterpart from DLM94 have also a 2MASS counterpart, so this leaves 15 XMM-Newton sources with a 2MASS counterpart and no counterpart in Daniel et al. (1994, PASP, 106, 281); of these, 3 were also detected by Chandra; of the other 12, 10 are outside the Chandra FOV, while two are within it (XMM-Newton sources 58 and 65). Source 65 was caught by XMM-Newton during the decay phase of a flare, which explains why it is not detected in the Chandra data. For source 58 there is no immediate explanation for this, since the light curve does not show evidence of a flare. No additional near-IR counterpart to the XMM-Newton sources was found within the Point Source Reject Table of the 2MASS Extended Mission. This table was created by the HEASARC in October 2008 based on the electronic version of Table 7 from the reference paper which was obtained from the CDS website, i.e., their catalog J/A+A/490/113 file table7.dat. This is a service provided by NASA HEASARC .
Orion Nebula Cluster Chandra HRC X-Ray Point Source Catalog
In the first of two companion papers on the Orion Nebula Cluster (ONC), the authors presented their analysis of a 63 ks Chandra HRC-I observation that yielded 742 X-ray detections within the 30' x 30' field of view. To facilitate their interpretation of the X-ray image, they compiled a multi-wavelength catalog of nearly 2900 known objects in the region by combining 17 different catalogs from the recent literature. They defined two reference groups: an infrared sample, containing all objects detected in the K band, and an optical sample comprising low-extinction, well-characterized ONC members. They showed for both samples that field object contamination is generally low. Their X-ray sources are primarily low-mass ONC members. The detection rate for optical sample stars increases monotonically with stellar mass from zero at the brown dwarf limit to ~100% for the most massive stars but shows a pronounced dip between 2 and 10 M<sub>sun</sub>. They determined L<sub>X</sub> and L<sub>X</sub>/L<sub>bol</sub> or all stars in their optical sample and utilized this information in their companion paper to study correlations between X-ray activity and other stellar parameters. In particular, the authors assembled an extensive catalog of known X-ray/optical/IR and radio objects that fell within the HRC FOV. In addition to their list of HRC sources and the Chandra source lists of Garmire et al. (2000, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/120/1426">CDS Cat. <J/AJ/120/1426></a>) and Schulz et al. (2001, CDS Cat. <J/ApJ/549/441>), they considered 14 catalogs from recent publications, producing a database of nearly 2900 distinct objects reported in at least one of the studies considered. A full list of references is given in the first column of Table 2 of the reference paper, along with a concise classification of the work and the referenced table number(s) from the original work. The HRC on board the Chandra X-Ray Observatory (Weisskopf et al., 2002PASP..114....1W) observed the ONC for 63.2ks on 2000 February 4. The pointing (R.A. = 5h 35m 17s, DE=-5{deg} 23' 16" (J2000.0)) was chosen to place the Trapezium region and the bright O star Theta<sup>1</sup> Ori C in the center of the field of view (FOV). A good fraction of the ONC region was included in the 30' x 30' HRC FOV. This HEASARC table lists the properties of the 742 X-ray sources detected in this observation as presented in the full version of Table 1 of the reference paper. This table was created by the HEASARC in March 2007 based on the CDS table J/ApJ/582/382, file table1.dat. This is a service provided by NASA HEASARC .
X-Ray Binaries Catalog
XRBCAT is a catalog of X-ray binaries, based on the van Paradijs (1996) compilation, and updated by Nick White to include all the new (mostly transient) systems discovered since then up until the last update (see below). The information in XRBCAT is basic and does not attempt to be complete. It includes the name of the source, the position, the pulse or orbital period (if one is known), the object class, a flux (a maximum and, if available, a minimum), and an optical V magnitude (if available). To reference XRBCAT, please use the following acknowledgment: "This paper utilized the HEASARC XRBCAT X-ray Binary catalog". Since it is a very time consuming task to keep track of all the new sources and discoveries, there may be incomplete or missing sources. This catalog was last updated on April 22, 1998. This is a service provided by NASA HEASARC .
Low-Mass X-Ray Binary Catalog (4th Edition, 2007)
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 .
ROSAT PSPC Galactic Center Soft X-Ray Source Catalog
This table contains a catalog of 107 point-like X-ray sources derived from a systematic analysis of all the ROSAT PSPC observations of the Galactic Center region performed in 1992-1993. Besides Sgr A*, the massive black hole at the galactic center, 41 X-ray sources have been positionally associated with already classified objects. Twenty are identified with foreground stars and five with known Low Mass X-ray Binaries (LMXBs). The majority of the sources in this catalog still remains unidentified. They are hard and/or severely absorbed and probably represent a large population of X-ray binaries located in the galactic center region, accreting at low accretion rates, and still largely unknown. Analyses were performed in 4 different energy ranges: 0.1 - 2.4 keV (PSPC channels 8 - 240, the total energy band T), 0.1 - 0.4 keV (PSPC channels 8 - 40, the soft energy band S), 0.5 - 0.9 keV (PSPC channels 52 - 90, the medium energy band), and 0.9 - 2.4 keV (PSPC channels 91 - 240, the hard energy band H). A maximum likelihood method was applied to the merged photon lists in each band. Only a detection liklihood larger than 10 (corresponding to a probability of a chance detection smaller than e<sup>-10</sup>) was considered to be a true source. This table was created by the HEASARC in March 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/368/835">CDS Catalog J/A+A/368/835</a> file table3.dat. This is a service provided by NASA HEASARC .
M 87 Chandra X-Ray Point Source Catalog
The ACIS instrument on board the Chandra X-Ray Observatory has been used to carry out the first systematic study of low-mass X-ray binaries (LMXBs) in M 87 (NGC 4486), the giant elliptical galaxy near the dynamical center of the Virgo Cluster. These images - with a total exposure time of 154 ks - are the deepest X-ray observations obtained as of 2004 of M 87. The authors identified 174 X-ray point sources, (contained in this Browse table) of which ~ 150 are likely LMXBs. This LMXB catalog was combined with deep F475W and F850LP images taken with ACS on the Hubble Space Telescope (HST) (as part of the ACS Virgo Cluster Survey) to examine the connection between LMXBs and globular clusters in M87. Of the 1688 globular clusters in the authors' catalog, a fraction f<sub>X</sub> = 3.6% +/- 0.5% contain an LMXB. M 87 (NGC 4486) was observed with the Chandra Advanced CCD Imaging Spectrometer (ACIS) for 121 ks on 2002 July 5-6. In this table, only the S3 chip data are used. The data were processed following the CIAO data reduction threads, including a correction for charge transfer inefficiency (CTI). In addition, the authors used 38 ks of archival ACIS observations of M 87 taken on 2000 July 29. These data were processed in a fashion similar to the 2002 July data, except that no CTI correction was possible because the data were telemetered in graded mode. All reductions were carried out with CIAO, version 2.3, coupled with CALDB, version 2.21. In order to combine the event files into a single image for point-source detection, the authors obtained relative offsets by matching the celestial coordinates of two X-ray point sources. The relative offset was ~ 0.5". The total exposure time of the co-added image, excluding four background flares totaling ~ 2.5 ks, was 154 ks. This table was created by the HEASARC in March 2007 based on the CDS table J/ApJ/613/279, file table1.dat. This is a service provided by NASA HEASARC .
SPICES Lynx Field Chandra X-Ray Source Catalog
This table contains the first results on field X-ray sources detected in a deep, 184.7 ks observation with the Advanced CCD Imaging Spectrometer (ACIS-I) on the Chandra X-Ray Observatory. The observations target the Lynx field (J2000.0 RA = 08h 48m and Dec = +44d 54') of SPICES, the Spectroscopic Photometric Infrared-Chosen Extragalactic Survey, which contains three known X-ray-emitting clusters at redshifts of z = 0.57, 1.26, and 1.27. Not including the known clusters, in the 17' x 17' ACIS-I field the authors detect 132 sources in the 0.5 - 2 keV (soft) X-ray band down to a 2.1-sigma limiting flux of ~ 1.7 x 10<sup>-16</sup> erg/cm<sup>2</sup>/s and 11 sources in the 2 - 10 keV (hard) X-ray band down to a 2.1-sigma limiting flux of ~ 1.3 x 10<sup>-15</sup> erg/cm<sup>2</sup>/s. The combined catalog contains a total of 153 X-ray sources, of which 42 are detected only in the soft band and 21 are detected only in the hard band. Confirming previous Chandra results, the authors find that the fainter sources have harder X-ray spectra, providing a consistent solution to the long-standing "spectral paradox". From deep optical and near-infrared follow-up data, 77% of the X-ray sources have optical counterparts to I = 24, and 71% of the X-ray sources have near-infrared counterparts to K<sub>s</sub> = 20. Four of the 24 sources in the near-IR field are associated with extremely red objects (EROs; I - K<sub>s</sub> >= 4). The authors have obtained spectroscopic redshifts with the Keck telescopes of 18 of the Lynx Chandra sources. These sources comprise a mix of broad-lined active galaxies, apparently normal galaxies, and two late-type Galactic dwarfs. Intriguingly, one Galactic source (number 72) is identified with an M7 dwarf exhibiting non-transient, hard X-ray emission. Thirteen of the Chandra sources are located within regions for which the authors have Hubble Space Telescope imaging. Nine of the sources are detected, showing a range of morphologies: several show compact cores embedded within diffuse emission, while others are spatially extended showing typical galaxy morphologies. Two of the Chandra sources in this subsample appear to be associated with mergers. ACIS-I observations of the Lynx field were obtained on 2000 May 3 (65 ks; OBS-ID 1708) and 2000 May 4 (125 ks; OBS-ID 927). Time intervals with background rates larger than 3 sigma over the quiescent value of ~ 0.30 counts s<sup>-1</sup> per chip in the 0.3 - 10 keV band were removed. This procedure gave 60.7 ks of effective exposure out of the first observation and 124 ks out of the second, for a total of 184.7 ks. The two observations are almost coincident on the sky, so that the total coverage is 298 arcmin<sup>2</sup>. The aim point for the observations was RA = 08h 48m 54.79s, Dec = +44d 54' 32.9" (J2000.0), and both exposures were obtained in the faint mode when ACIS was at a temperature of -120 C. The Galactic absorbing column for this field is N<sub>H</sub> = 2 x 10<sup>20</sup> cm<sup>-2</sup>. The position angle of the observations was 258.45 degrees. Cosmology-dependent parameters are calculated for two models: an Einstein-de Sitter (EdS) universe consistent with previous work in this field (H<sub>0</sub> = 50 h<sub>50</sub> km s<sup>-1</sup> Mpc<sup>-1</sup>, Omega<sub>M</sub> = 1, and Omega<sub>Lambda</sub> = 0) and the dark energy cosmology (DEC) universe favored by recent work on high-redshift supernovae and fluctuations in the cosmic microwave background (H<sub>0</sub> = 65 km s<sup>-1</sup> Mpc<sup>-1</sup>, Omega<sub>M</sub> = 0.35, and Omega<sub>Lambda</sub> = 0.65). This table was created by the HEASARC in April 2007 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/123/2223">CDS catalog J/AJ/123/2223</a> files table1.dat, table2.dat and table3.dat. This is a service provided by NASA HEASARC .
Small Magellanic Cloud Wing Survey Chandra X-Ray Point Source Catalog
The authors have detected 523 X-ray sources in a survey of the Small Magellanic Cloud (SMC) Wing with the Chandra X-ray Observatory. By cross-correlating the X-ray data with optical and near-infrared catalogs, they have found 300 matches. Using a technique that combines X-ray colors and X-ray to optical flux ratios, they have been able to assign preliminary classifications to 265 of the objects. The identifications include 4 pulsars, 1 high-mass X-ray binary (HMXB) candidate, 34 stars and 185 active galactic nuclei (AGN). In addition, the authors have classified 32 sources as hard AGN which are likely absorbed by local gas and dust, and 9 soft AGN whose nature is still unclear. Considering the abundance of HMXBs discovered so far in the Bar of the SMC the number that have been detected in the Wing is low. Observations in the Wing of the SMC were made from 2005 July to 2006 March with Chandra. The survey consisted of 20 fields, with exposure times ranging from 8.6 - 10.3 ks. X-ray parameters for 523 sources detected in the Wing of the SMC with Chandra are presented. For each source equatorial coordinates, positional error, net counts (total counts minus background counts) in the 0.5 - 8.0 keV band, signal-to-noise of the detection and source flux in the 0.5 - 8.0 keV band are given. The median, compressed median and normalized quartile ratio of the photon energy distribution, determined using quantile analysis, are given for sources with three or more counts. For the sources that have optical counterparts the V- and R-band magnitudes, B-V color, X-ray to optical flux ratios based on the V- and R-band magnitudes, and a preliminary classification for the sources are given. This table was created by the HEASARC in June 2008 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/383/330">CDS Catalog J/MNRAS/383/330</a> file table2.dat. This is a service provided by NASA HEASARC .
Ultraluminous X-Ray Sources in Nearby Galaxies Catalog
One hundred and seven ultraluminous X-ray sources (ULXs) with 0.3-10.0 keV luminosities in excess of 10<sup>39</sup> erg s<sup>-1</sup> are identified in a complete sample of 127 nearby galaxies. The sample includes all galaxies within 14.5 Mpc above the completeness limits of both the Uppsala Galaxy Catalogue and the Infrared Astronomical Satellite survey. The galaxy sample spans all Hubble types, a four-decade range in mass, 7.5 < log (M/M<sub>sun</sub>) < 11.4, and in star formation rate, 0.0002 < SFR(M<sub>sun</sub> yr<sup>-1</sup>) <= 3.6. ULXs are detected in this sample at rates of one per 3.2 x 10<sup>10</sup> M<sub>sun</sub>, one per ~0.5 M<sub>sun</sub> yr<sup>-1</sup> star formation rate, and one per 57 Mpc<sup>3</sup> corresponding to a luminosity density of ~2 x 10<sup>37</sup> erg s<sup>-1</sup> Mpc<sup>-3</sup>. At these rates, the authors estimate as many as 19 additional ULXs remain undetected in fainter dwarf galaxies within the survey volume. An estimated 14 objects, or 13%, of the 107 ULX candidates are expected to be background sources. The differential ULX luminosity function shows a power-law slope alpha ~ -0.8 to -2.0 with an exponential cutoff at ~20 x 10<sup>39</sup> erg s<sup>-1</sup> with precise values depending on the model and on whether the ULX luminosities are estimated from their observed numbers of counts or, for a subset of candidates, from their spectral shapes. Extrapolating the observed luminosity function predicts at most one very luminous ULX, L<sub>X</sub> ~ 10<sup>41</sup> erg s<sup>-1</sup>, within a distance as small as 100 Mpc. The luminosity distribution of ULXs within the local universe cannot account for the recent claims of luminosities in excess of 2 x 10<sup>41</sup> erg s<sup>-1</sup>, requiring a new population class to explain these extreme objects. This table was created by the HEASARC in November 2011 based on an electronic version of Table 1 from the reference paper that was obtained from the ApJ web site. This is a service provided by NASA HEASARC .
NGC 1333 Chandra X-Ray Point Source Catalog
NGC 1333, a highly active star formation region within the Perseus molecular cloud complex, has been observed on 2000 July 12.96 - 13.48 with the ACIS-I detector on board the Chandra X-Ray Observatory. The aim point of the array was 3 29 06.1, +31 19 38 (J2000,0 RA and Dec), the satellite roll angle was 95.7 degrees, and the effective exposure time after removing time intervals contaminated by background flaring was 37.8 ks. In this image with a sensitivity limit in luminosity of ~10<sup>28</sup> erg/s for X-ray sources at the 318 pc distance of NGC 1333, 127 X-ray sources were detected, most with sub-arcsecond positional accuracy. While 32 of these sources appear to be foreground stars and extragalactic background objects, 95 X-ray sources are identified with known cluster members. The X-ray luminosity function of the discovered young stellar object (YSO) population spans a range of log L<sub>X</sub> ~= 28.0 - 31.5 erg s<sup>-1</sup> in the 0.5 - 8 keV band, and the absorption column densities range from log N<sub>H</sub> ~=20 to 23 cm<sup>-2</sup>. Most of the sources have plasma temperatures between 0.6 and 3 keV, but a few sources show higher temperatures up to ~7 keV. Comparison with K-band source counts indicates that all of the known cluster members with K < 12 and about half of the members with K > 12 were detected. (K ~= 11, the peak of the K-band luminosity function, corresponds to 0.2 - 0.4 M_solar stars for a cluster age of ~1 Myr). Seven of the 20 known YSOs in NGC 1333 which are producing jets or molecular outflows were detected, as well as one deeply embedded object without outflows. No evident difference in X-ray emission of young stars with and without outflows is found. This present table contains X-ray, optical and near-infrared information on the 109 X-ray sources that were detected above a source significance threshold of 1 x 10<sup>-6</sup> in any of 3 energy bands: soft: 0.5 - 2.0 keV, hard: 2.0 - 8.0 keV, or full: 0.5 - 8.0 keV, excluding 8 sources that were deemed to be spurious on visual examination of the images. The faintest on-axis source emerging from the wavelet detection procedure has 5 extracted counts, corresponding to a source of log L<sub>X</sub> ~ 28.0 in the total (0.5 - 8.0 keV) band for a source with negligible interstellar absorption (A<sub>V</sub> ~ 1) and a typical source spectrum of a kT ~ 1 keV thermal plasma. This limit increases to 28.6 (29.3) if the absorption is increased to A<sub>V</sub> ~ 5 (10). The sensitivity decreases by a factor of 4 at the edge of the field compared to the central regions. 80 of the significant 109 sources (73%) have counterparts in a non-X-ray band. This table does not include 18 tentative X-ray sources listed in Table 3 of the reference paper that were found by the authors by searching for concentrations of photons spatially coincident with known sources from near-IR, mm/sub-mm, and radio catalogs of this region which did not reach the detection significance given above. Most of these tentative sources are believed to be real sources. This table was created by the HEASARC in March 2007 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/575/354">CDS catalog J/ApJ/575/354</a> files table1.dat and table2.dat. This is a service provided by NASA HEASARC .
ScienceDex guides
Understand access before you commit
These curated guides explain access requirements, typical timelines, costs, and reuse considerations for widely used research datasets.
Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.