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51. Chandra Typical Galactic Plane Region Point Source Catalog

ID:: ivo://nasa.heasarc/chantypgpr
Title:: Chandra Typical Galactic Plane Region Point Source Catalog
Short Name:: CHANTYPGPR
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: Using the Chandra Advanced CCD Imaging Spectrometer Imaging array (ACIS-I), the authors carried out a deep hard X-ray observation of the Galactic plane region at a location (l, b) ~ (28.5 degrees, 0.0 degrees), where no discrete X-ray source had been reported previously. They detected 274 new point X-ray sources (4-sigma or greater confidence in any of the 3 energy bands 0.5 - 3.0 keV, 3.0 - 8.0 keV or 0.5 - 8.0 keV), as well as strong Galactic diffuse emission within two partially overlapping ACIS-I fields (~ 250 square arcminutes in total). The point-source sensitivity was ~ 3 x 10-15 ergs/s/cm2 in the 2 - 10 keV band and ~ 2 x 10-16 erg/s/cm2 in the 0.5 - 2 keV band The sum of all the detected point-source fluxes accounts for only ~ 10% of the total X-ray flux in the field of view. Only 26 point sources were detected in both the soft and hard bands, indicating that there are two distinct classes of X-ray source distinguished by their spectral hardness ratios. The surface number density of the hard sources is only slightly higher than that measured in high Galactic latitude regions, indicating that the majority of the hard sources are background AGNs. Following up the Chandra observation, the authors performed a near-infrared (NIR) survey with SofI at ESO/NTT. Almost all the soft X-ray sources have been identified in the NIR, and their spectral types are consistent with main-sequence stars, suggesting that most of them are nearby X-ray-active stars. On the other hand, only 22% of the hard sources had near-IR counterparts, which are presumably Galactic. From X-ray and near-IR spectral study, they are most likely to be quiescent cataclysmic variables. This Browse table was created by the HEASARC in December 2006 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/635/214/">CDS Catalog J/ApJ/635/214/</a>, the file table1.dat. This is a service provided by NASA HEASARC .

52. Chandra Variable Guide Star Catalog

ID:: ivo://nasa.heasarc/chanvguide
Title:: Chandra Variable Guide Star Catalog
Short Name:: CHANVGUIDE
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: Variable stars have been identified among the optical-wavelength light curves of guide stars used for pointing control of the Chandra X-ray Observatory. The authors present a catalog of these variable stars along with their light curves and ancillary data. Variability was detected to a lower limit of 0.02 mag amplitude in the 4000-10000 Angstroms range using the photometrically stable Aspect Camera on board the Chandra spacecraft. The Chandra Variable Guide Star Catalog (VGUIDE) contains 827 stars, of which 586 are classified as definitely variable and 241 are identified as possibly variable. Of the 586 definite variable stars, the authors believe 319 are new variable star identifications. Types of variables in the catalog include eclipsing binaries, pulsating stars, and rotating stars. The variability was detected during the course of normal verification of each Chandra pointing and results from analysis of over 75,000 guide star light curves from the Chandra mission. The VGUIDE catalog represents data from only about 9 years of the Chandra mission. Future releases of VGUIDE will include newly identified variable guide stars as the mission proceeds. An important advantage of the use of space data to identify and analyze variable stars is the relatively long observations that are available. The Chandra orbit allows for observations up to 2 days in length. Also, guide stars were often used multiple times for Chandra observations, so many of the stars in the VGUIDE catalog have multiple light curves available from various times in the mission. The catalog is presented as both online data associated with this paper (from which this HEASARC representation was created) and as a public Web interface at <a href="http://cxc.harvard.edu/vguide/">http://cxc.harvard.edu/vguide/</a>. Light curves with data at the instrumental time resolution of about 2 s, overplotted with the data binned at 1 ks, can be viewed on the above-mentioned public Web interface and downloaded for further analysis. (This HEASARC Browse table also contains links to these light curves). VGUIDE is a unique project using data collected during the mission that would otherwise be ignored. The stars available for use as Chandra guide stars are generally 6-11 magnitudes and are commonly spectral types A and later. Due to the selection of guide stars entirely for positional convenience, this catalog avoids the possible bias of searching for variability in objects where it is to be expected. Statistics of variability compared to spectral type indicate the expected dominance of A-F stars as pulsators. Eclipsing binaries are consistently 20%-30% of the detected var iables across all spectral types. This table was created by the HEASARC in July 2010 based on the electronic version of Table 4 from the paper which was obtained from the Astrophysical Journal web site. This is a service provided by NASA HEASARC .

53. Chandra XAssist Source List

ID:: ivo://nasa.heasarc/cxoxassist
Title:: Chandra XAssist Source List
Short Name:: Chan/XAssist
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: This database table contains the latest Chandra XAssist source list. XAssist is a NASA-funded project for the automation of X-ray astrophysics, with emphasis on galaxies. It is capable of data reprocessing, source detection, and preliminary spatial, temporal, and spectral analysis for all sources with sufficient counts. The bulk of the system is written in Python, which in turn drives underlying software, e.g., CIAO for Chandra data. Pipelines running on Chandra observations of galaxies have generated the source list which comprises this HEASARC table. The pipeline also includes fields requested by users for various projects, most notably observations of a sample of quasars and several deep field observations have been processed. Note that the pipline processing is completely automated; therefore, users should visually inspect the results of any queries. This table was first created by the HEASARC in May 2005 based on the Chandra source list available at the XAssist website. In September 2010, the HEASARC switched over to using the "pipeline4" Chandra source list. It is updated on a weekly basis when and if the XAssist source list file at <a href="https://asd.gsfc.nasa.gov/xassist/pipeline4/chandra/master_srclist.csv">https://asd.gsfc.nasa.gov/xassist/pipeline4/chandra/master_srclist.csv</a> is updated. This is a service provided by NASA HEASARC .

54. ChIcAGO Survey Chandra X-Ray Source Catalog

ID:: ivo://nasa.heasarc/chicagocxo
Title:: ChIcAGO Survey Chandra X-Ray Source Catalog
Short Name:: CHICAGOCXO
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: This table contains results from the 'Chasing the Identification of ASCA Galactic Objects' (ChIcAGO) survey, which is designed to identify the unknown X-ray sources discovered during the ASCA Galactic Plane Survey (AGPS). Little is known about most of the AGPS sources, especially those that emit primarily in hard X-rays (2-10 keV) within the X-ray flux range from ~ 10-13 to 10-11 erg cm-2 s-1. In ChIcAGO, the sub-arcsecond localization capabilities of Chandra have been combined with a detailed multi-wavelength follow-up program, with the ultimate goal of classifying the > 100 unidentified sources in the AGPS. Overall to date, 93 unidentified AGPS sources have been observed with Chandra as part of the ChIcAGO survey. A total of 253 X-ray point sources have been detected in these Chandra observations within 3 arcminutes of the original ASCA positions. The authors have identified infrared and optical counterparts to the majority of these sources, using both new observations and catalogs from existing Galactic plane surveys. X-ray and infrared population statistics for the X-ray point sources detected in the Chandra observations reveal that the primary populations of Galactic plane X-ray sources that emit in the X-ray flux range from ~ 10-13 to 10-11 erg cm-2 s-1 are active stellar coronae, massive stars with strong stellar winds that are possibly in colliding wind binaries, X-ray binaries, and magnetars. There is also another primary population that is still unidentified but, on the basis of its X-ray and infrared properties, likely comprises partly Galactic sources and partly active galactic nuclei. A total of 93 AGPS sources have been observed with Chandra as part of the ChIcAGO survey, of which 84 were imaged with ACIS-S and 9 were imaged with HRC-I. The ChIcAGO Chandra observations took place over a 3.5 yr period, from 2007 January to 2010 July. The Chandra exposure times ranged from ~ 1 to 10 ks. All the details of these Chandra observations are listed in Table 1 of the reference paper. The initial automated analysis of these Chandra observations was conducted using the ChIcAGO Multi-wavelength Analysis Pipeline (MAP), described in Section 2.2 of the reference paper. ChIcAGO MAP takes the ACIS-S or HRC-I Chandra observation of an AGPS source field and detects and analyzes all point sources within 3 arcminutes, equivalent to the largest likely position error, for the original AGPS source positions supplied by Sugizaki et al. (2001, ApJS, 134, 77). The authors then performed a more detailed X-ray analysis and counterpart study for those 74 sources with > 20 X-ray counts, as such sources are approximately within the original AGPS sources X-ray flux range (see Sections 3.2 and 3.3 of the reference paper). Infrared and optical follow-up were primarily performed on those ChIcAGO sources having > 20 X-ray counts. In order to determine which optical and infrared sources are counterparts to ChIcAGO sources, the authors used a technique similar to that described by Zhao et al. (2005, ApJS, 161, 429), using their Equation (11). If the separation between a ChIcAGO source's wavdetect position and its possible counterpart is less than the quadratic sum of their 3-sigma positional errors and the 3-sigma Chandra pointing error, then the X-ray and optical (or infrared) sources are likely to be associated. The 1-sigma positional errors for all sources in the 2MASS PSC and GLIMPSE catalogs are 0.1 arcseconds and 0.3 arcseconds, respectively. USNO B has an astrometric accuracy of < 0.25 arcseconds. The authors have assumed that the error distributions of the Chandra observations, Chandra pointing, and USNO B Catalog are all Gaussian for the purposes of identifying possible counterparts to the ChIcAGO sources. This table was created by the HEASARC in June 2014 based on electronic versions of Tables 1, 2 and 12 from the reference paper which were obtained from the ApJS website. This is a service provided by NASA HEASARC .

55. Collinder 261 Chandra X-Ray Point Source Catalog

ID:: ivo://nasa.heasarc/cr261cxo
Title:: Collinder 261 Chandra X-Ray Point Source Catalog
Short Name:: CR261CXO
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: This table contains some of the results from the first X-ray study of Collinder 261 (Cr 261), which at an age of 7 Gyr is one of the oldest open clusters known in the Galaxy. This observation with the Chandra X-Ray Observatory was aimed at uncovering the close interacting binaries in Cr 261, and reached a limiting X-ray luminosity of LX ~ 4 x 1029 erg s-1 (0.3-7 keV) for stars in the cluster. The authors detected 107 sources within the cluster half-mass radius rh, and they estimate that among the sources with LX >~ 1030 erg s-1, about 26 are associated with the cluster. They identify a mix of active binaries and candidate active binaries, candidate cataclysmic variables, and stars that have "straggled" from the main locus of CR 261 in the color-magnitude diagram. Based on a deep optical source catalog of the field, the authors estimate that Cr 261 has an approximate mass of 6500 Msun, roughly the same as the old open cluster NGC 6791. The X-ray emissivity of Cr 261 is similar to that of other old open clusters, supporting the trend that they are more luminous in X-rays per unit mass than old populations of higher (globular clusters) and lower (the local neighborhood) stellar density. This implies that the dynamical destruction of binaries in the densest environments is not solely responsible for the observed differences in X-ray emissivity. Cr 261 was observed with the Advanced CCD Imaging Spectrometer (ACIS) on board Chandra starting 2009 November 9 14:50 UTC, for a total exposure time of 53.8 ks (ObsID 11308). The observation was made in Very Faint, Timed exposure mode, with a single frame exposure time of 3.2 s. Kharchenko et al. (2013, A&A, 558, A53) estimate that the radius of Cr 261 is ~ 14.1 arcminutes. This is considerably larger than a single ACIS chip (8 4 x 8 4 arcminute2) and therefore the authors placed the center of the cluster (J2000.0 RA = 12h 38m 06.0s, Dec = -68o 22' 01" according to Kharchenko et al. 2013) close to the I3 aimpoint so that a larger contiguous part of the cluster could be imaged (see Figure 1 in the reference paper). The CCDs used were I0, I1, I2, and I3 from the ACIS-I array, and S2 and S3 from the ACIS-S array. The authors limited the X-ray analysis to the data from chips I0, I1, I2, and I3. The S2 and S3 chips lie far from the I3 aimpoint, giving rise to large positional errors on any sources detected on them. Such large errors make it hard to identify optical counterparts, and thus to classify the sources. Source detection was done in soft (0.3-2.0 keV), hard (2-7 keV) and broad (0.3-7 keV) energy bands. The CIAO source detection routine wavdetect was run for eight wavelet scales ranging from 1.0 to 11.3 pixels. The wavdetect detection threshold (sigthresh) was set at 10-7. The corresponding expected number of spurious detections per wavelet scale is 0.42 for all four ACIS chips combined, or 3.35 in total for all wavelet scales. The authors ran wavdetect for the three different energy bands and then cross-correlated the resulting source lists to obtain a master X-ray source list. They detected 113 distinct X-ray sources. To check if any real sources were missed, they ran wavdetect again with a detection threshold of 10-6, which increased the expected total number of spurious detections to 33.5, and found a total of 151 distinct X-ray sources with more than two counts (0.3-7 keV) in this case. The positions of 7 of the extra 38 sources were found to match those of short-period binaries discovered by Mazur et al. (1995, MNRAS, 273, 59; see Section 3.4). Close, interacting binaries are plausible real X-ray sources, and indeed the expected number of chance alignments between the Chandra detections and the binaries in the Mazur catalog is very low, as discussed in Section 3.5 of the reference paper. It is therefore likely that at least these seven additional sources are real, but given the ~ 34 spurious detections that are expected, the authors do not believe that there are many more real sources among the extra detections. They flagged the sources that are only found for sigthresh = 10-6, but kept them in the master source list. This HEASARC table contains the list of 151 X-ray sources found by wavdetect using a detection threshold of 10-6 from Table 1 of the reference paper. Information about the 135 optical counterparts to these X-ray sources is available in the HEASARC table CR261OID (based on Table 2 of the reference paper) to which this current table has links. This table was created by the HEASARC in June 2017 based upon the machine-readable version of Table 1 from the reference paper, the catalog of Chandra sources in Cr 261, that was obtained from the ApJ web site. This is a service provided by NASA HEASARC .

56. Collinder 261 Chandra X-Ray Source Optical Counterparts Catalog

ID:: ivo://nasa.heasarc/cr261oid
Title:: Collinder 261 Chandra X-Ray Source Optical Counterparts Catalog
Short Name:: CR261OID
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: This table contains some of the results from the first X-ray study of Collinder 261 (Cr 261), which at an age of 7 Gyr is one of the oldest open clusters known in the Galaxy. This observation with the Chandra X-Ray Observatory was aimed at uncovering the close interacting binaries in Cr 261, and reached a limiting X-ray luminosity of LX ~ 4 x 1029 erg s-1 (0.3-7 keV) for stars in the cluster. The authors detected 107 sources within the cluster half-mass radius rh, and they estimate that among the sources with LX >~ 1030 erg s-1, about 26 are associated with the cluster. They identify a mix of active binaries and candidate active binaries, candidate cataclysmic variables, and stars that have "straggled" from the main locus of CR 261 in the color-magnitude diagram. Based on a deep optical source catalog of the field, the authors estimate that Cr 261 has an approximate mass of 6500 Msun, roughly the same as the old open cluster NGC 6791. The X-ray emissivity of Cr 261 is similar to that of other old open clusters, supporting the trend that they are more luminous in X-rays per unit mass than old populations of higher (globular clusters) and lower (the local neighborhood) stellar density. This implies that the dynamical destruction of binaries in the densest environments is not solely responsible for the observed differences in X-ray emissivity. Cr 261 was observed with the Advanced CCD Imaging Spectrometer (ACIS) on board Chandra starting 2009 November 9 14:50 UTC, for a total exposure time of 53.8 ks (ObsID 11308). The observation was made in Very Faint, Timed exposure mode, with a single frame exposure time of 3.2 s. Kharchenko et al. (2013, A&A, 558, A53) estimate that the radius of Cr 261 is ~ 14.1 arcminutes. This is considerably larger than a single ACIS chip (8 4 x 8 4 arcminute2) and therefore the authors placed the center of the cluster (J2000.0 RA = 12h 38m 06.0s, Dec = -68o 22' 01" according to Kharchenko et al. 2013) close to the I3 aimpoint so that a larger contiguous part of the cluster could be imaged (see Figure 1 in the reference paper). The CCDs used were I0, I1, I2, and I3 from the ACIS-I array, and S2 and S3 from the ACIS-S array. The authors limited the X-ray analysis to the data from chips I0, I1, I2, and I3. The S2 and S3 chips lie far from the I3 aimpoint, giving rise to large positional errors on any sources detected on them. Such large errors make it hard to identify optical counterparts, and thus to classify the sources. The authors retrieved optical images of Cr 261 in the B and V bands from the ESO public archive. These data were taken as part of the ESO Imaging Survey (EIS; program ID 164.O-0561). The observations of Cr 261 were made using the Wide Field Imager (WFI), mounted on the 2.2 m MPG/ESO telescope at La Silla, Chile. After correcting the X-ray source positions for the (almost negligible) boresight correction (0.06 =/- 0.07 arcseconds in RA and 0.09 +/- 0.08 arcseconds in Dec), the authors matched their X-ray source list with the entire optical source list, using 95% match radii. For 89 unique X-ray sources, they found 124 optical matches; of the latter, 104 are present in both the V and B images, while for 20 there is only a V or B detection. The authors also inspected the area around each X-ray source in the WFI images by eye, and discovered that five more X-ray sources have candidate optical counterparts that are saturated and therefore missing from their optical catalog. Finally, they added to the list of candidate counterparts six optical sources that lay just outside the 95% match radius, but inside the 3-sigma radius. In total, 98 of the 151 unique X-ray sources were thus matched to one or more optical sources. This HEASARC table contains the list of the 135 optical counterparts to 98 of the 151 X-ray sources from Table 2 of the reference paper. Information about the 151 X-ray sources is available in the HEASARC table CR261CXO (based on Table 1 of the reference paper) to which this current table has links. This table was created by the HEASARC in June 2017 primarily based upon the machine-readable version of Table 2 from the reference paper, the catalog of optical counterparts to Chandra sources in Cr 261, that was obtained from the ApJ web site. The information on the X-ray source positions was taken from the machine-readable version of Table 1 from the reference paper that was also obtained from the ApJ web site. This is a service provided by NASA HEASARC .

57. Cygnus OB2 Association Chandra X-Ray Point Source Catalog 2

ID:: ivo://nasa.heasarc/cygob2cxo2
Title:: Cygnus OB2 Association Chandra X-Ray Point Source Catalog 2
Short Name:: CYGOB2CXO2
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: This table contains a catalog of 1696 X-ray sources detected in the massive star-forming region (SFR) Cygnus OB2 and extracted from two archival Chandra observations of the center of the region. A deep source extraction routine, exploiting the low background rates of Chandra observations was employed to maximize the number of sources extracted. Observations at other wavelengths were used to identify low count-rate sources and remove likely spurious sources. Monte Carlo simulations were also used to assess the authenticity of these sources. X-ray spectra were fitted with thermal plasma models to characterize the objects and X-ray light curves were analyzed to determine their variability. The authors used a Bayesian technique to identify optical or near-IR counterparts for 1501 (89%) of our sources, using deep observations from the INT Photometric H-alpha Survey, the Two Micron All Sky Survey (2MASS), and the UKIRT Infrared Deep Sky Survey-Galactic Plane Survey. 755 (45%) of these objects have six-band r', H-alpha, i', J, H, and K optical and near-IR photometry. From an analysis of the Poisson false-source probabilities for each source they estimate that their X-ray catalog includes <1% of false sources, and an even lower fraction when only sources with optical or near-IR associations are considered. A Monte Carlo simulation of the Bayesian matching scheme allows this method to be compared to more simplified matching techniques and enables the various sources of error to be quantified. The catalog of 1696 objects presented here includes X-ray broad-band fluxes, spectral model fits, and optical and near-IR photometry in what is one of the largest X-ray catalogs of a single SFR to date. The high number of stellar X-ray sources detected from relatively shallow observations confirms the status and importance of Cygnus OB2 as one of our Galaxy's most massive SFRs. This table was created by the HEASARC in October 2009 based on electronic versions of Tables 2, 3 and 4 from the reference paper which were obtained from the CDS (their catalog J/ApJS/184/84 files table2.dat, table3.dat and table4.dat). This is a service provided by NASA HEASARC .

58. Cygnus OB2 Association Chandra X-Ray Point Source Catalog

ID:: ivo://nasa.heasarc/cygob2cxo
Title:: Cygnus OB2 Association Chandra X-Ray Point Source Catalog
Short Name:: CYGOB2CXO
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: The aim of this study is to identify the so far unknown low mass stellar population of the ~2 Myr old Cygnus OB2 star forming region, and to investigate the X-ray and near-IR stellar properties of its members. The authors analyzed a 97.7ks Chandra ACIS-I observation pointed at the core of the Cygnus OB2 region. Sources were detected using the PWDETECT code and were positionally correlated with optical and near-IR catalogs from the literature. Source events were extracted with the ACIS EXTRACT package. X-ray variability was characterized through the Kolmogorov-Smirnov test and spectra were fitted using absorbed APEC thermal plasma models. The authors detected 1003 X-ray sources. Of these, 775 have near-IR counterparts and are expected to be almost all associated with Cygnus OB2 members. From near-IR color-color and color-magnitude diagrams, they estimate a typical absorption toward Cygnus OB2 of AV ~ 7.0 mag. Although the region is young, very few stars (~ 4.4%) show disk-induced excesses in the near-IR. X-ray variability is detected in ~ 13% of the sources, but this fraction increases, up to 50%, with increasing source statistics. Flares account for at least 60% of the variability. Despite being generally bright, all but 2 of the 26 detected O-type and early B-type stars are not significantly variable. Typical X-ray spectral parameters are log NH ~ 22.25 (cm-2) and kT ~ 1.35 keV with 1-sigma dispersion of 0.2 dex and 0.4 keV, respectively. Variable and flaring sources have harder spectra with median kT = 3.3 and 3.8 keV, respectively. OB stars are typically softer (kT ~ 0.75 keV). X-ray luminosities range between 1030 and 1031 erg s-1 for intermediate-mass and low-mass stars, and between 2.5 x 1030 and 6.3 x 1033 erg s-1 for OB stars. Cygnus OB2 was observed with the ACIS detector on board the Chandra X-ray Observatory (CXO) on 2004 January 16 (Obs.Id. 4511; PI: E. Flaccomio). The ACIS-I 17' x 17' field of view is covered by 4 chips each with 1024 x 1024 pixels (scale 0.49 arcseconds per pixel). The observation was pointed towards J2000.0 (RA,Dec) = (20 33 12.2, +41 15 00.7). An SNR threshold of 4.5 sigma was chosen which resulted in an initial source list of 1054 sources, 51 of which were subsequently rejected as either instrumental artifacts or multiple detections of the same source with different spatial scales. An additional 10 of the 1003 X-ray sources in the present table are likely spurious statistical fluctuations rather than real sources. This table was created by the HEASARC in March 2008 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/464/211">CDS catalog J/A+A/464/211</a> files table1.dat, table2.dat and table3.dat. This is a service provided by NASA HEASARC .

59. Cygnus TeV Source Chandra X-Ray Point Source Catalog

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 .

60. DEEP2 Galaxy Redshift Survey Fields Chandra Point Source Catalog

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 deg2 DEEP2 (XDEEP2) survey fields, which consist of four ~ 0.7 - 1.1 deg2 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 10-16 erg cm-1 s-1. 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 10-14 erg cm-1 s-1), 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 RAB < 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 .

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51. Chandra Typical Galactic Plane Region Point Source Catalog

52. Chandra Variable Guide Star Catalog

53. Chandra XAssist Source List

54. ChIcAGO Survey Chandra X-Ray Source Catalog

55. Collinder 261 Chandra X-Ray Point Source Catalog

56. Collinder 261 Chandra X-Ray Source Optical Counterparts Catalog

57. Cygnus OB2 Association Chandra X-Ray Point Source Catalog 2

58. Cygnus OB2 Association Chandra X-Ray Point Source Catalog

59. Cygnus TeV Source Chandra X-Ray Point Source Catalog

60. DEEP2 Galaxy Redshift Survey Fields Chandra Point Source Catalog

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