X-Ray Selected High-z AGN Catalog

X-Ray Selected High-z AGN Catalog XSHZAGNCXO ivo://nasa.heasarc/xshzagncxo NASA/GSFC HEASARC Kalfountzou et al. 2026-10-02 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov AGN This table contains the results from an analysis of the largest high-redshift (z > 3) X-ray-selected active galactic nucleus (AGN) sample to date, combining the Chandra Cosmological Evolution Survey and Chandra Multi-wavelength Project surveys and doubling the previous samples. The sample comprises 209 X-ray-detected AGNs, over a wide range of rest-frame 2-10 keV luminosities log LX = 43.3 - 46.0 erg/s. X-ray hardness ratios show that ~39 per cent of the sources are highly obscured, NH > 1022 cm-2, in agreement with the ~37 per cent of type-2 AGNs found in this sample based on their optical classification. For ~26 per cent of objects, there are mismatched optical and X-ray classifications. Utilizing the 1/Vmax method, the authors confirm that the comoving space density of all luminosity ranges of AGNs decreases with redshift above z > 3 and up to z ~ 7. With a significant sample of AGNs (N = 27) at z > 4, it is found that both source number counts in the 0.5-2 keV band and comoving space density are consistent with the expectation of a luminosity-dependent density evolution (LDDE) model at all redshifts, while they exclude the luminosity and density evolution (LADE) model. The measured comoving space density of type-1 and type-2 AGNs shows a constant ratio between the two types at z > 3. These results for both AGN types at these redshifts are consistent with the expectations of LDDE model. The high-redshift AGN sample used in this work has been selected from the C-COSMOS X-ray catalog, combining the spectroscopic and photometric information available from the identification catalogue of X-ray C-COSMOS sources (Civano et al. 2011, ApJ, 741, 91; 2012, ApJS, 201, 30) and the ChaMP (Chandra Multi-wavelength Project) X-ray catalog using only the 323 ChaMP ObsIDs overlapping with Sloan Digital Sky Survey (SDSS; Richards et al. 2006, AJ, 131, 2766) DR5 imaging. This table was created by the HEASARC in March 2016 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/445/1430">CDS catalog J/MNRAS/445/1430</a> file tablea1.dat. This is a service provided by NASA HEASARC . 2014MNRAS.445.1430K https://heasarc.gsfc.nasa.gov/W3Browse/all/xshzagncxo.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=xshzagncxo& GET text/xml 180 99999 true 340.9458 -9.6855 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=xshzagncxo GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_xshzagncxo&Action=More+Options&Action=Parameter+Search&ConeAdd=1 GALAXY CATALOG 0.0166666666666667 X-ray public xshzagncxo X-Ray Selected High-z AGN Catalog name Source Designation meta.id;meta.main char nullable ra Right Ascension degree pos.eq.ra;meta.main double nullable dec Declination degree pos.eq.dec;meta.main double nullable redshift Spectroscopic Redshift src.redshift double nullable phot_redshift_min_limit Limit Flag for Photometric Redshift Lower Bound char nullable phot_redshift_min Photometric Redshift Lower Bound src.redshift.phot;stat.min double nullable phot_redshift Photometric Redshift src.redshift.phot double nullable phot_redshift_max Photometric Redshift Upper Bound src.redshift.phot;stat.max double nullable sb_flux The 0.5-2keV Flux Converted to Gamma=1.8 erg/s/cm^2 phot.flux;em.X-ray.soft double nullable log_lx The 2-10keV Luminosity log(erg/s) phys.luminosity;em.X-ray double nullable nh The Absorption Column Density cm^-2 phys.columnDensity double nullable bii Galactic Latitude degree pos.galactic.lat double nullable hardness_ratio_max Hardness Ratio Upper Bound phot.flux;arith.ratio;em.X-ray.medium;stat.max double nullable lii Galactic Longitude degree pos.galactic.lon double nullable xray_type_code Number Code [1/2] Indicates X-Ray Type Based on N_H=10^22 cm^-2 Limit meta.code short nullable nh_limit Limit Flag for the Absorption Column Density meta.code;phys.columnDensity char nullable optical_type_code Number Code [1/2] Indicates Optical Type meta.code;src.class short nullable survey_code Number Code [1/2] Indicates Survey: 1=ChaMP; 2=C-COSMOS meta.code short nullable sb_flux_code Number Code [1/2] Indicates 1=Detection in Soft Band; 2=Estimated from HB or FB meta.code;phot.flux;em.X-ray.soft short nullable hardness_ratio_min Hardness Ratio Lower Bound phot.flux;arith.ratio;em.X-ray.medium;stat.min double nullable hardness_ratio Hardness Ratio phot.flux;arith.ratio;em.X-ray.medium double nullable "__x_ra_dec" System unit vector column double nullable "__y_ra_dec" System unit vector column double nullable "__z_ra_dec" System unit vector column double nullable "__row" System index column char nullable