- ID:
- ivo://nasa.heasarc/gc47tuccxo
- Title:
- 47 Tuc Globular Cluster Chandra X-Ray Point Source Catalog (2005 Version)
- Short Name:
- GC47TUCCXO
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors have detected 300 X-ray sources within the half-mass radius (2.79') of the globular cluster 47 Tucanae in a deep (281 ks) Chandra exposure. They perform photometry and simple spectral fitting for our detected sources and construct luminosity functions, X-ray color-magnitude, and color-color diagrams. Eighty-seven X-ray sources show variability on timescales from hours to years. Thirty-one of the new X-ray sources are identified with chromospherically active binaries from the catalogs of Albrow and coworkers (2001, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/559/1060">CDS Catalog <J/ApJ/559/1060></a>). The authors estimate that the total number of neutron stars in 47 Tuc is of order 300, reducing the discrepancy between theoretical neutron star retention rates and observed neutron star populations in globular clusters. The data used in this paper are from the 2000 and 2002 Chandra observations of the globular cluster 47 Tuc. The 2000 observations, initially described in Grindlay et al. (2001, Science 292, 2290), were performed with the ACIS-I CCD array at the telescope focus, while the 2002 observations placed the back-illuminated ACIS-S aim point at the focus for maximum low-energy sensitivity. The authors combined the results from wavdetect source detection runs with a threshold probability of 1 x 10<sup>-5</sup>, in two energy bands (0.5 - 2.0 keV and 0.5 - 6.0 keV for the 2000 observations, and (0.3 - 2.0 keV and 0.3 - 6.0 keV for the 2002 observations), to make independent source lists for the 2000 and 2002 observations, given in Tables 2 and 3 of the reference paper, which have been combined in the present HEASARC table. A total of 146 sources were detected in this way in the 2000 observations (entries with dataset_year = 2000), while 300 sources were detected in the 2002 observations (dataset_year = 2002). A total of 143 of the sources were clearly detected in both observations, while only three of the sources from the 2000 observations were not detected in the 2002 observations. See also the related <a href="gc47tuccx2.html">2017 source catalog</a>. This table was created by the HEASARC in June 2007 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/625/796">CDS Catalog J/ApJ/625/796</a> files table2.dat, table3.dat, and (part of) table5.dat. This is a service provided by NASA HEASARC .
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- ID:
- ivo://nasa.heasarc/gc47tuccx2
- Title:
- 47 Tuc Globular Cluster Chandra X-Ray Point Source Catalog (2017 Version)
- Short Name:
- GC47TUCCX2
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors combined Chandra ACIS observations of the globular cluster 47 Tucanae (47 Tuc) from 2000, 2002, and 2014-2015 to create a deeper X-ray source list and study some of the faint radio millisecond pulsars (MSPs) present in this cluster. This work combined 180 ks of new Chandra ACIS data on 47 Tuc with 370 ks of archival data and used improved algorithms to generate a new source catalog, finding 81 new sources for a total of 370 within the half-mass region (2.79 arcsec) of the cluster. The majority of the newly identified sources are in the crowded core region, indicating cluster membership. The authors associated five of the new X-ray sources with chromospherically active BY Dra or W UMa variables identified by Albrow et al. (2001, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/559/1060">CDS Cat. <J/ApJ/559/1060></a>). See also the related <a href="gc47tuccxo.html">2005 source catalog</a>. This table was created by the HEASARC in September 2020 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/472/3706">CDS Catalog J/MNRAS/472/3706</a> files table2.dat, table4.dat, and table5.dat. The optical names from Albrow et al. (2001) were subsequently corrected in October 2020 in order to use the recommendation from the CDS Dictionary of Nomenclature of Celestial Objects. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/ulxngcat
- Title:
- Ultraluminous X-Ray Sources in Nearby Galaxies Catalog
- Short Name:
- ULXNGCAT
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- 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 .
- ID:
- ivo://nasa.heasarc/wd1cxo
- Title:
- Westerlund 1 Chandra X-Ray Point Source Catalog
- Short Name:
- WD1CXO
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The nature of the X-ray point source population within the young massive cluster Westerlund 1 (Wd 1) is investigated. Chandra X-ray Observatory (CXO) observations were used to determine the X-ray properties of emitters within Wd 1, while a comprehensive multi-wavelength dataset was employed to constrain their nature. Wd 1 (l=339.5, b=-0.4) was observed with the CXO Advanced CCD Spectrometer Spectroscopic array on 2005 May 22 for 18 ks (sequence 6283) and 2005 June 20 for 42 ks (sequence 5411). 241 sources were found above a sensitivity threshold that corresponded to a 10<sup>-6</sup> chance per PSF element of detecting a spurious source. X-ray emission from a multitude of different stellar sources within Wd 1, including both evolved high mass and low-mass pre-MS stars, is found. This table was created by the HEASARC in May 2008 based on CDS table J/A+A/477/147 files table1.dat and table3.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/w40sfrcxo
- Title:
- W 40 Star-Forming Region Chandra X-Ray Point Source Catalog
- Short Name:
- W40SFRCXO
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The young stellar cluster illuminating the W40 H II region, one of the nearest massive star-forming regions (SFRs), has been observed with the ACIS detector on board the Chandra X-ray Observatory. Due to its high obscuration, this is a poorly studied stellar cluster with only a handful of bright stars visible in the optical band, including three OB stars identified as primary excitation sources. The authors detect 225 X-ray sources, of which 85% are confidently identified as young stellar members of the region. Two potential distances of the cluster, 260 pc and 600 pc, are used in the paper. Supposing the X-ray luminosity function of SFRs to be universal, it supports a 600 pc distance as a lower limit for W40 and a total population of at least 600 stars down to 0.1 M<sub>sun</sub> under the assumption of a coeval population with a uniform obscuration. In fact, there is strong spatial variation in K<sub>s</sub>-band-excess disk fraction and non-uniform obscuration due to a dust lane that is identified in absorption in optical, infrared, and X-ray. The dust lane is likely part of a ring of material which includes the molecular core within W40. In contrast to the likely ongoing star formation in the dust lane, the molecular core is inactive. The star cluster has a spherical morphology, an isothermal sphere density profile, and mass segregation down to 1.5 M<sub>sun</sub>. However, other cluster properties, including a <= 1 Myr age estimate and ongoing star formation, indicate that the cluster is not dynamically relaxed. X-ray diffuse emission and a powerful flare from a young stellar object are also reported in the reference paper. This table was created by the HEASARC in March 2011 based on electronic versions of Tables, 1, 2 and 4 of the reference paper which were obtained from the ApJ web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/xbootesoid
- Title:
- XBOOTES:NDWFSBootesFieldOptical&NearIRCounterparts
- Short Name:
- XBOOTESOID
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The XBootes Survey is a 5 ks Chandra survey of the Bootes Field of the NOAO Deep Wide-Field Survey (NDWFS). This survey is unique in that it is the largest (9.3 square degrees) contiguous region imaged in X-ray with complementary deep optical and near-infrared (near-IR) observations. The authors present a catalog of the optical counterparts to the 3213 X-ray point sources detected in the XBootes survey. Using a Bayesian identification scheme, they successfully identified optical counterparts for 98% of the X-ray point sources. The optical colors suggest that the optically detected galaxies are a combination of z < 1 massive early-type galaxies and bluer star-forming galaxies whose optical AGN emission is faint or obscured, whereas the majority of the optically detected point sources are likely quasars over a large redshift range. This large-area, X-ray-bright, optically deep survey enables the authors to select a large subsample of sources (773) with high X-ray to optical flux ratios (f<sub>X</sub>/f<sub>o</sub> > 10). These objects are likely high-redshift and/or dust-obscured AGNs. These sources have generally harder X-ray spectra than sources with 0.1 < f<sub>X</sub>/f<sub>o</sub> < 10. Of the 73 X-ray sources with no optical counterpart in the NDWFS catalog, 47 are truly optically blank down to R ~ 25.5 (the average 50% completeness limit of the NDWFS R-band catalogs). These sources are also likely to be high-redshift and/or dust-obscured AGNs. The 9.3 square degrees region of sky chosen to match the area covered with the NDWFS was observed by ACIS-I on the Chandra X-Ray Observatory over a 2 week time interval in 2003 March and April. The data were taken in 126 separate pointings, each observed for ~ 5 ks. The CIAO 3.0.2 wavelet detection algorithm (wavdetect; Freeman et al. 2002) was used to detect X-ray sources in the total (0.5 - 7.0 keV) band data. A probability threshold of 5 x 10-5 was chosen as the best compromise between maximizing the completeness while minimizing the number of spurious detections. The X-ray catalog comprises 3293 unique X-ray sources with >= 4 counts in the total-band images (Paper II). The authors expect only ~ 35 of these sources to be spurious in the full survey (Paper II). For the matching with cataloged optical counterparts, the authors only considered the 3213 X-ray sources that overlap with the NDWFS area. The authors include all multiply matched sources with >1% probability of being the correct optical counterpart. This table contains the X-ray and optical characteristics of the matched optical/X-ray catalog for the Chandra sources in the XBootes and NDWFS survey, and is Version 1.0, dated 21st June 2005. This table was created in November 2006 by the HEASARC based on the file xbootes_cat_xray_opt_IR_21jun_v1.0.txt obtained from the NOAO ftp area <a href="https://www.noao.edu/noao/noaodeep/XBootesPublic/">https://www.noao.edu/noao/noaodeep/XBootesPublic/</a>. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/xbootes
- Title:
- XBOOTES: NDWFS Bootes Field X-Ray Point Source Catalog
- Short Name:
- XBootes
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The XBootes table contains the X-Ray point source catalog from a Chandra survey of the 9 square degrees Bootes field of the NOAO Deep Wide-Field Survey (NDWFS). This XBootes survey consists of 126 separate contiguous ACIS-I observations each of approximately 5000 s in duration. These unique Chandra observations allowed the authors to search for large-scale structure and to calculate X-ray source statistics over a wide, contiguous field of view with arcsecond angular resolution and uniform coverage. Optical spectroscopic follow-up observations and the rich NDWFS data set will allow the authors to identify and classify these X-ray-selected sources. Using wavelet decomposition, they have detected 4642 point sources with n >= 2 counts. In order to keep their detections ~ 99% reliable, they have limited their list to sources with n >= 4 counts. For a 5000 s observation and assuming a canonical unabsorbed active galactic nucleus (AGN) type X-ray spectrum, a 4 count on-axis source corresponds to a flux of 4.7 x 10<sup>-15</sup> ergs cm<sup>-2</sup> s<sup>-1</sup> in the soft (0.5-2 keV) band, 1.5 x 10<sup>-14</sup> ergs cm<sup>-2</sup> s<sup>-1</sup> in the hard (2-7 keV) band, and 7.8 x 10<sup>-15</sup> ergs cm<sup>-2</sup> s<sup>-1</sup> in the full (0.5-7 keV) band. The full 0.5-7 keV band n >= 4 count list contained in this HEASARC table has 3293 point sources. In addition to the point sources, 43 extended sources (not included in this HEASARC table) have been detected, consistent with the depth of these observations and the number counts of clusters. Presented here in the X-ray point source catalog for the XBootes survey are the source positions, X-ray fluxes, hardness ratios, and their uncertainties, for the 3293 sources with >= 4 counts in the full band. This table was created by the HEASARC in February 2006 based on the machine-readable version of Table 3 in the above paper which was obtained from the electronic ApJ website. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/hcgxrbs
- Title:
- X-Ray Observations of Compact Group Galaxies
- Short Name:
- HCGXRBS
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This catalog presents the study of a sample of 15 compact groups (CGs) observed with Chandra/ACIS, Swift/UVOT and Spitzer/IRAC-MIPS for which archival data exist, allowing the authors to obtain SFRs, stellar masses, sSFRs and X-ray fluxes and luminosities for individual, off-nuclear point sources, which they summed to obtain total X-ray luminosities originating in off-nuclear point sources in a galaxy. Details on the Swift and Spitzer observations and data for systems in this sample can be found in Tzanavaris et al. (2010ApJ...716..556T) and Lenkic et al. (2016MNRAS.459.2948L). For Chandra/ACIS observations, see Tzanavaris et al. (2014ApJS..212....9T) and Desjardins et al. (2013ApJ...763..121D; 2014ApJ...790..132D). The authors obtained total galaxy X-ray luminosities, L<sub>X</sub>, originating from individually detected point sources in a sample of 47 galaxies in 15 compact groups of galaxies (CGs). For the great majority of the galaxies, they found that the detected point sources most likely are local to their associated galaxy, and are thus extragalactic X-ray binaries (XRBs) or nuclear active galactic nuclei (AGNs). For spiral and irregular galaxies, they found that, after accounting for AGNs and nuclear sources, most CG galaxies are either within the +/- 1 sigma scatter of the Mineo et al. L<sub>X</sub>-star formation rate (SFR) correlation or have higher L<sub>X</sub> than predicted by this correlation for their SFR. These "excesses" may be due to low metallicities and high interaction levels. For elliptical and S0 galaxies, after accounting for AGNs and nuclear sources, most CG galaxies were found to be consistent with the Boroson et al. L<sub>X</sub>-stellar mass correlation for low-mass XRBs, with larger scatter, likely due to residual effects such as AGN activity or hot gas. Assuming non-nuclear sources are low- or high-mass XRBs, the authors used appropriate XRB luminosity functions to estimate the probability that stochastic effects can lead to such extreme L<sub>X</sub> values. They found that, although stochastic effects do not in general appear to be important, for some galaxies there is a significant probability that high L<sub>X</sub> values can be observed due to strong XRB variability. This table was created by the HEASARC in May 2019 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/817/95">CDS Catalog J/ApJ/817/95</a> file table3.dat This is a service provided by NASA HEASARC .
