- ID:
- ivo://nasa.heasarc/cygob2xmm
- Title:
- Cygnus OB2 Association XMM-Newton X-Ray Point Source Catalog
- Short Name:
- CYGOB2XMM
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Cyg OB2 is one of the most massive associations of O-type stars in our Galaxy. Despite the large interstellar reddening towards Cyg OB2, many studies, spanning a wide range of wavelengths, have been conducted to more clearly understand this association. X-ray observations provide a powerful tool to overcome the effect of interstellar absorption and study the most energetic processes associated with the stars in Cyg OB2. The author analyses XMM-Newton data to investigate the X-ray and UV properties of massive O-type stars as well as low-mass pre-main sequence stars in Cyg OB2. Six XMM-Newton observations of the core of Cyg OB2 were obtained. In the analysis, the author paid particular attention to the variability of the X-ray bright OB stars, especially the luminous blue variable candidate Cyg OB2 #12. He found that X-ray variability is quite common among the stars in Cyg OB2. While short-term variations are restricted mostly to low-mass pre-main sequence stars, one third of the OB stars display long-term variations. The X-ray flux of CygO B2 #12 varies by 37%, over timescales from days to years, while its mean log L<sub>X</sub>/L<sub>bol</sub> amounts to -6.10. These properties suggest that Cyg OB2 wind. Two other X-ray bright O-type stars (MT91 516 and CPR2002A11) display variations that suggest they are interacting wind binary systems. This table lists the general properties of the X-ray sources detected in Cyg OB2 with the EPIC cameras onboard XMM-Newton as given in Table 2 of the reference paper. An additional list of the properties of the sources detected inside Cyg OB2 with the two UV filters of the OM instrument onboard XMM-Newton which was contained in Table 4 of the reference paper is not included herein. This table was created by the HEASARC in December 2011 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/536/A31">CDS Catalog J/A+A/536/A31</a> file table2.dat. This is a service provided by NASA HEASARC .
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- ID:
- ivo://nasa.heasarc/cygtevcxo
- Title:
- Cygnus TeV Source Chandra X-Ray Point Source Catalog
- Short Name:
- CYGTEVCXO
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- A 50 ks Chandra observation of the unidentified TeV source in Cygnus reported by the High Energy Gamma-Ray Astronomy (HEGRA) collaboration reveals no obvious diffuse X-ray counterpart. However, 240 pointlike X-ray sources are detected within or nearby the extended TeV J2032+4130 source region, of which at least 36 are massive stars and two may be radio emitters. That the HEGRA source is a composite, having as a counterpart the multiple pointlike X-ray sources that are observed, cannot be ruled out. Indeed, the distribution of pointlike X-ray sources appears nonuniform and concentrated broadly within the extent of the TeV source region. A hypothesis is offered for the origin of the very high energy gamma-ray emission in Cyg OB2 based on the local acceleration of TeV-range cosmic rays and the differential distribution of OB versus less massive stars in this association. The region of TeV J2032+4130 was observed by Chandra on 2004 July 12 for a total effective exposure time of 48,728 seconds using the Advanced CCD Imaging Specrometer imaging array (ACIS-I). The observation was centered on J2000.0 coordinates (RA, Dec) = )20 32 07.0, +41 30 30). This table contains the list of the 240 pointlike sources which were detected in the ACIS-I data and their 2MASS near-IR counterparts, if any are found within 3" of the X-ray sources. 130 (54%) of the 240 X-ray sources have 2MASS counterparts within these error radii. This table was created by the HEASARC in February 2007 based on the electronic version of Table 1 from the above reference which was obtained from the ApJ website. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/xdeep2
- Title:
- DEEP2 Galaxy Redshift Survey Fields Chandra Point Source Catalog
- Short Name:
- XDEEP2
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the X-ray point-source catalog produced from the Chandra Advanced CCD Imaging Spectrometer (ACIS-I) observations of the combined ~3.2 deg<sup>2</sup> DEEP2 (XDEEP2) survey fields, which consist of four ~ 0.7 - 1.1 deg<sup>2</sup> fields. The combined total exposures across all four XDEEP2 fields range from ~ 10 ks to 1.1 Ms. The authors detect X-ray point sources in both the individual ACIS-I observations and the overlapping regions in the merged (stacked) images. They find a total of 2976 unique X-ray sources within the survey area with an expected false-source contamination of ~ 30 sources (<~ 1%). In their paper, the authors present the combined log N-log S distribution of sources detected across the XDEEP2 survey fields and find good agreement with the Extended Chandra Deep Field and Chandra-COSMOS fields to f_(X,0.5-2keV)_ ~ 2 x 10<sup>-16</sup> erg cm<sup>-1</sup> s<sup>-1</sup>. Given the large survey area of XDEEP2, they additionally place relatively strong constraints on the log N-log S distribution at high fluxes (f_(X,0.5-2keV) ~ 3 x 10<sup>-14</sup> erg cm<sup>-1</sup> s<sup>-1</sup>), and find a small systematic offset (a factor ~ 1.5) toward lower source numbers in this regime, when compared to smaller area surveys. The number counts observed in XDEEP2 are in close agreement with those predicted by X-ray background synthesis models. Additionally, the authors present a Bayesian-style method for associating the X-ray sources with optical photometric counterparts in the DEEP2 catalog (complete to R<sub>AB</sub> < 25.2) and find that 2126 (~ 71.4% +/- 2.8%) of the 2976 X-ray sources presented here have a secure optical counterpart with a <~ 6% contamination fraction. The present table provides the DEEP2 optical source properties (e.g., magnitude, redshift) as part of the X-ray-optical counterpart catalog. This table was created by the HEASARC in October 2012 based on electronic versions of Tables 5 and 7 from the reference paper which were obtained from the ApJS web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/twodfqsoz
- Title:
- 2dF QSO Redshift (2QZ) Survey
- Short Name:
- TWODFQSOZ
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The final catalog of the 2dF QSO Redshift Survey (2QZ) is based on Anglo-Australian Telescope 2dF spectroscopic observations of 44,576 color-selected (u, b<sub>J</sub>, r) objects with 18.25 < b<sub>J</sub> < 20.85 selected from automated plate measurement scans of UK Schmidt Telescope (UKST) photographic plates. The 2QZ comprises 23,338 quasi-stellar objects (QSOs), 12,292 galactic stars (including 2,071 white dwarfs) and 4,558 compact narrow emission-line galaxies. The authors obtained a reliable spectroscopic identification for 86 per cent of objects observed with 2dF. They also report on the 6dF QSO Redshift Survey (6QZ), based on UKST 6dF observations of 1,564 brighter (16 < b<sub>J</sub> < 18.25) sources selected from the same photographic input catalog. In total, the authors identified 322 QSOs spectroscopically in the 6QZ. The completed 2QZ is, by more than a factor of 50, the largest homogeneous QSO catalog ever constructed at these faint limits (b<sub>J</sub> < 20.85) and high QSO surface densities (35 QSOs/deg<sup>2</sup>). As such, it represents an important resource in the study of the Universe at moderate-to-high redshifts. The survey area comprised 30 UKST fields, arranged in two 75 degrees by 5 degrees declination strips, one passing across the South Galactic Gap centered on Dec = -30 degrees (the SGP strip), and the other across the North Galactic Gap centered on Dec = 0 degrees (referred to in the reference paper as the equatorial strip, but also known as the NGP strip. The total survey area is 721.6 deg<sup>2</sup>, when allowance is made for regions of sky excised around bright stars. Spectroscopic observations of the input catalogue were made with the 2dF instrument at the Anglo-Australian Telescope (AAT; the 2QZ sample) and the 6dF instrument at the UKST (the 6QZ sample). 2dF spectroscopic observations began in January 1997 and were completed in April 2002. Six-degree Field observations were performed over the period 2001 March-2002 September. This online catalog was created by the HEASARC in October 2010 based on the machine-readable table 2qz.dat obtained from the CDS (their catalog VII/241). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/dixon
- Title:
- Dixon Master List of Radio Sources (Version 43)
- Short Name:
- Dixon
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This database table is the Dixon Master List of Radio Sources (Version 43, dated November 1981) which contains flux densities for known radio sources detected at a variety of frequencies. The Master List of Radio Sources was prepared by combining about thirty catalogs of radio sources that were available as of that date into a common format. Notice that this is a list of observations, not of individual sources, and that an entry in this table corresponds to an observation of a radio source at a particular frequency from a particular source catalog: also, no attempt was made by the author to use the same name for the same source, e.g., the source 3C 273 appears more than a dozen times under a variety of names such as PKS 1226+02, NRAO400, CTA 53, etc. This database table was recreated at the HEASARC in June 2005 after it was discovered that the positions had been incorrectly precessed. The original input table used for both the previous and current HEASARC Dixon tables was the 43rd version of the Master List, dated November 1981. It was obtained from the Colorado node of the Astrophysics Data System (ADS), the now-defunct HTTP link <adswww.colorado.edu/catalogs/rad_msl43.html>, and apparently was provided by D. E. Harris on or after 1991. Notice that the version of this table that is currently available at CDS (<a href="https://cdsarc.cds.unistra.fr/ftp/cats/VII/2A">https://cdsarc.cds.unistra.fr/ftp/cats/VII/2A</a>) is, according to Andernach (1989, Bull. Inf. Centre Donnees Stellaires, 37, 139), the 42nd edition (dated 1976) and has only 79493 entries compared to 84510 entries in the HEASARC table. 49 duplicate entries were removed from the HEASARC table in June 2019. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/etgalcxo
- Title:
- Early-Type Galaxies Chandra X-Ray Point Source Catalog
- Short Name:
- ETGALCXO
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- 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 .
- ID:
- ivo://nasa.heasarc/etgalxray
- Title:
- Early-Type Galaxies X-Ray Luminosities Catalog
- Short Name:
- ETGALXRAY
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a catalog of X-ray luminosities for 401 early-type galaxies (and 24 other galaxies which were listed in previuous studies as early but which have LEDA T-types >= -1.5), of which 136 are based on newly analysed ROSAT PSPC pointed observations. The remaining luminosities are taken from the literature and converted to a common energy band, spectral model and distance scale. In their paper, the authors use this sample to fit the L<sub>X</sub>/L<sub>B</sub> relation for early-type galaxies and find a best-fit slope for the catalog of ~ 2.2. The authors demonstrate the influence of group-dominant galaxies on the fit and present evidence that the relation is not well modeled by a single power-law fit. They also derive estimates of the contribution to galaxy X-ray luminosities from discrete-sources and conclude that they provide L<sub>(discrete-source-contribution)</sub>/L<sub>B</sub> ~ 29.5 erg s<sup>-1</sup>/L<sub>Bsun</sub>. The authors compare this result with luminosities from their catalog. Lastly, they examine the influence of environment on galaxy X-ray luminosity and on the form of the L<sub>X</sub>/L<sub>B</sub> relation. They conclude that although environment undoubtedly affects the X-ray properties of individual galaxies, particularly those in the centres of groups and clusters, it does not change the nature of whole populations. The sample of early-type galaxies was selected from the Lyon-Meudon Extragalactic Data Archive (LEDA). This catalog at that time contained information on ~ 100,000 galaxies, of which ~ 40,000 had redshift and morphological data. Galaxies were selected using the following criteria: (i) Morphological Type T < -1.5 (i.e. E, E-S0 and S0 galaxies). (ii) Virgo-corrected recession velocity V <= 9,000 km s<sup>-1</sup>. (iii) Apparent Magnitude B<sub>T</sub> <= 13.5. The redshift and apparent magnitude restrictions were chosen in order to minimize the effects of incompleteness on their sample. The LEDA catalogue is known to be 90 per cent complete at B<sub>T</sub> = 14.5, so the selection should be close to statistical completeness. The selection process produced ~ 700 objects. The authors then cross-correlated this list with a list of public ROSAT PSPC pointings. Only pointings within 30 arcminutes of the target were accepted, as, further off-axis, the PSPC point-spread function becomes large enough to make analysis problematic. This left 209 galaxies with X-ray data available. The authors also added data from previously published catalogs, ROSAT PSPC All-Sky Survey values from Beuing et al. (1999, MNRAS, 302, 209), and Einstein IPC values from Fabbiano et al. (1992, ApJS, 80, 531) and Roberts et al. (1991, ApJS, 75, 751). These other references use a range of models to fit the data, different wavebands, distances and blue luminosities. O'Sullivan et al. corrected for these differences by converting the catalogs to a common set of values, as used for their own results. All of the X-ray luminosities have been converted to a common format based on a reliable distance scale (assuming H<sub>0</sub> = 75 km s<sup>-1</sup> Mpc<sup>-1</sup>), and correcting for differences in spectral fitting techniques and waveband. This table was created by the HEASARC in October 2010 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/328/461">CDS catalog J/MNRAS/328/461</a> file table3.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/hricfa
- Title:
- Einstein Catalog HRI CFA Sources
- Short Name:
- Einstein/HRI
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This database table consists of a preliminary source list for the Einstein Observatory's High Resolution Imager (HRI). The source list, obtained from EINLINE, the Einstein On-line Service at the Smithsonian Astrophysical Observatory (SAO), contains basic information about the sources detected with the HRI. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/hrideep
- Title:
- Einstein Catalog HRI Deep Survey
- Short Name:
- EinstHRIDeep
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This database table contains primary HRI source parameters for the 202 HRI sources found in the Einstein Deep Survey. The Einstein Deep Survey (EDS) program consisted of very deep X-ray exposures in selected regions of the sky at high galactic latitude. The main purposes of the survey are to investigate the nature of the extragalactic X-ray background through direct source counts at very low flux levels and to study the nature of the very faint X-ray sources which comprise a significant fraction, if not all, of the soft X-ray background. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/hriexo
- Title:
- Einstein Catalog HRI ESTEC Sources
- Short Name:
- HRIEXO
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Einstein High Resolution Imager (HRI) consisted of a micro-channel plate. This database table has been generated at the EXOSAT observatory by automatically processing all the HRI images. Both the images and detected sources are available. This catalog has not been cleaned or checked. Users should beware of two possible problems: (1) spurious detections caused by extended sources have not been checked, and (2) there may be a one-pixel offset in some positions. For HRI images, one pixel is one arcsecond. (The images are rebinned from the original 0.5 arcseconds.) This is a service provided by NASA HEASARC .
