- ID:
- ivo://nasa.heasarc/cosxfirmwc
- Title:
- COSMOSFieldX-Ray&FIRDetectedAGNMultiwavelengthPropertiesCatalog
- Short Name:
- COSXFIRMWC
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The coeval AGN and galaxy evolution and the observed local relations between super-massive black holes (SMBHs) and galaxy properties suggest some connection or feedback between SMBH growth and galaxy build-up. The authors looked for correlations between properties of X-ray detected AGN and their far-infrared (FIR) detected host galaxies, to find quantitative evidences for this connection, highly debated in recent years. They exploit the rich multi-wavelength data set (from X-ray to FIR) that is available in the COSMOS field for a large sample (692 sources) of AGN and their hosts, in the redshift range 0.1 < z < 4, and use X-ray data to select AGN and determine their properties (intrinsic luminosity and nuclear obscuration), and broad-band (from UV to FIR) spectral energy distribution (SED) fitting to derive host galaxy properties, viz., the stellar mass (M<sub>*</sub>) and the star formation rate (SFR). The authors find that the AGN 2-10 keV luminosity (L<sub>X</sub>) and the host galaxy 8-1000 um star formation luminosity (L<sup>SF</sup><sub>IR</sub>) are significantly correlated. However, the average host L<sup>SF</sup><sub>IR</sub> has a flat distribution in bins of AGN L<sub>X</sub>, while the average AGN L<sub>X</sub> increases in bins of host L<sup>SF</sup><sub>IR</sub>, with a logarithmic slope of ~ 0.7, in the redshifts range 0.4 < z < 1.2. In the reference paper, the authors also discuss the comparison between the distribution of these two quantities and the predictions from hydrodynamical simulations. Finally, they find that the average column density (N<sub>H</sub>) shows a positive correlation with the host M<sub>*</sub>, at all redshifts, but not with the SFR (or L<sup>SF</sup><sub>IR</sub>). This translates into a negative correlation with specific SFR. These results are in agreement with the idea that BH accretion and SFRs are correlated, but occur with different variability time scales. The presence of a positive correlation between N<sub>H</sub> and host M<sub>*</sub> suggests that the X-ray N<sub>H</sub> is not entirely due to the circumnuclear obscuring torus, but may also include a contribution from the host galaxy. This table summarizes the multiwavelength properties of the 692 AGN-host systems detected in the COSMOS field both in the X-ray and in the FIR (the X-FIR sample). This table was created by the HEASARC in July 2017, based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/602/A123">CDS Catalog J/A+A/602/A123</a> file table1.dat, which contains the multiwavelength properties of the 692 sources in the X-FIR sample. This is a service provided by NASA HEASARC .
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Search Results
212. Crab Pulsar Timing
- ID:
- ivo://nasa.heasarc/crabtime
- Title:
- Crab Pulsar Timing
- Short Name:
- CRABTIME
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The CRABTIME database contains the Crab Pulsar Monthly Ephemeris covering the period from Feb 15 1982 (MJD=45015) to (close to) the present that was created Dr. Andrew Lyne and collaborators at Jodrell Bank Observatory. This database is periodically updated to include recent data as these become available. To assist astronomers, the HEASARC has created two new parameters which were not present in the original Jodrell Bank tables, the pulsar period and its first derivative, using the standard relations between period (P) and frequency 'Nu' (P=1./Nu) and their first derivatives (P_dot = -Nu_dot/Nu<sup>2</sup>). The assumed pulsar position used in the reductions is <pre> RA (1950.0) 05 31 31.406 DEC (1950.0) +21 58 54.391 RA (2000.0) 05 34 31.973 DEC (2000.0) +22 00 52.061 </pre> This HEASARC version of the "Jodrell Bank Crab Pulsar Timing Results, Monthly Ephemeris" is updated within one week of any changes to the tables available on the Web at <a href="http://www.jb.man.ac.uk/pulsar/crab.html">http://www.jb.man.ac.uk/pulsar/crab.html</a>. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/crates
- Title:
- CRATES Flat-Spectrum Radio Source Catalog
- Short Name:
- CRATES
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors have assembled an 8.4 GHz survey of bright, flat-spectrum (alpha > -0.5) radio sources with nearly uniform extragalactic (|b| > 10 degrees) coverage for sources brighter than a 4.8 GHz flux density S_4.8GHz = 65 mJy. The catalog is assembled from existing observations (especially the Cosmic Lens All-Sky Survey, CLASS, and the Wright et al. PMN-CA survey), augmented by reprocessing of archival VLA and ATCA data and by new observations to fill in coverage gaps. The authors refer to this program as CRATES, the Combined Radio All-Sky Targeted Eight-GHz Survey. The resulting catalog provides precise positions, subarcsecond structures, and spectral indices for some 11,000 sources. The authors describe the morphology and spectral index distribution of the sample and comment on the survey's power to select several classes of interesting sources, especially high-energy blazars. Comparison of CRATES with other high-frequency surveys also provides unique opportunities for identification of high-power radio sources. This table contains 14467 entries, where each entry corresponds to an 8.4-GHz counterpart source (or absence thereof) to one of 11,131 4.8-GHz sources. The number of entries exceeds the number of 4.8-GHz sources because there are many cases in which there are multiple (from 2 - 20) 8.4-GHz counterparts to a single 4.8-GHz source. There are also 762 entries in which no 8.4-GHz counterpart was detected (morph_type = 'N'). This table was created by the HEASARC in August 2007 based on the electronic version of Table 5 obtained from the electronic ApJ web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rrs8c38mhz
- Title:
- 8C Revised Rees Survey 38-MHz Source Catalog
- Short Name:
- RRS8C38MHZ
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a revised machine-readable source list for the Rees 38-MHz (or '8C') survey with improved positions and no redundancy. The Rees 38-MHz survey covers an area of about 1 sr north of declination +60 degrees. The angular resolution is 4.5 x 4.5 cosec(Dec) arcmin<sup>2</sup> and the limiting flux density over much of the survey area is about 1 Jy. Both of these figures were an improvement by nearly an order of magnitude on previous surveys at this frequency. Users of these data should consult and cite the original survey paper by Rees as primary reference (1990MNRAS.244..233R) with the present publication (1995MNRAS.274..447H) as a supplementary revision. The recommended style of reference is thus: "The revised Rees 38-MHz survey (Rees 1990, catalogue revised Hales et. al 1995)." In the Hales et al. (1995) paper, the authors aimed to improve the accuracy of the source positions to <~ 1 arcminute, so that a search radius smaller than the survey resolution of 4.5 arcminutes was practicable everywhere. Note that for interest the source list includes data on some sources at declinations lower than +60 degrees, but that the right ascension coverage is not complete below +60 degrees. This table was created in November 2010 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/VIII/31">CDS catalog VIII/31</a> file 8c.dat. 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 .
- ID:
- ivo://nasa.heasarc/ami10c15gz
- Title:
- 10C Survey at 15.7 GHz Radio Source Catalog
- Short Name:
- AMI10C15GZ
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- In a previous paper (AMI Consortium 2011, MNRAS, 415, 2699: Paper I), the observational, mapping and source-extraction techniques used for the Tenth Cambridge (10C) Survey of Radio Sources were described. Here, the first results from the survey, carried out using the Arcminute Microkelvin Imager (AMI) Large Array (LA) at an observing frequency of 15.7 GHz, are presented. The survey fields cover an area of ~ 27 deg<sup>2</sup> to a flux-density completeness of 1 mJy. Results for some deeper areas, covering ~ 12 deg<sup>2</sup>, which are wholly contained within the total areas and complete to 0.5 mJy, are also presented. The completeness for both areas is estimated to be at least 93 per cent. The 10C survey is the deepest radio survey of any significant extent (>~ 0.2 deg<sup>2</sup>) above 1.4 GHz. The 10C source catalogue contains 1897 entries detected above a flux density threshold of > 4.62 sigma, and is available here and at the authors' web site <a href="http://www.mrao.cam.ac.uk/surveys/10C">http://www.mrao.cam.ac.uk/surveys/10C</a>. The source catalog has been combined with that of the Ninth Cambridge Survey to calculate the 15.7-GHz source counts. A broken power law is found to provide a good parametrization of the differential count between 0.5 mJy and 1 Jy. The measured source count has been compared with that predicted by de Zotti et al. (2005, A&A, 431, 893, and the model is found to display good agreement with the data at the highest flux densities. However, over the entire flux-density range of the measured count (0.5 mJy to 1 Jy), the model is found to underpredict the integrated count by ~ 30 per cent. Entries from the source catalog have been matched with those contained in the catalogues of the NRAO VLA Sky Survey and the Faint Images of the Radio Sky at Twenty-cm survey (both of which have observing frequencies of 1.4 GHz). This matching provides evidence for a shift in the typical 1.4-GHz spectral index to 15.7-GHz spectral index of the 15.7-GHz-selected source population with decreasing flux density towards sub-mJy levels - the spectra tend to become less steep. Automated methods for detecting extended sources, developed in Paper I, have been applied to the data; ~ 5 per cent of the sources are found to be extended relative to the LA-synthesized beam of ~ 30 arcsec. Investigations using higher resolution data showed that most of the genuinely extended sources at 15.7 GHz are classical doubles, although some nearby galaxies and twin-jet sources were also identified. This table was created by the HEASARC in August 2011 based on an electronic version of Table 1 of the reference paper which was obtained from the 10C Survey web site <a href="http://www.mrao.cam.ac.uk/surveys/10C/">http://www.mrao.cam.ac.uk/surveys/10C/</a>. This is a service provided by NASA HEASARC .
- 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 .
- 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 A<sub>V</sub> ~ 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 N<sub>H</sub> ~ 22.25 (cm<sup>-2</sup>) 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 10<sup>30</sup> and 10<sup>31</sup> erg s<sup>-1</sup> for intermediate-mass and low-mass stars, and between 2.5 x 10<sup>30</sup> and 6.3 x 10<sup>33</sup> erg s<sup>-1</sup> 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 .
- 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 .
- 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 .
