High-Redshift X-Ray AGN Catalog from Chandra Surveys

209 X-ray-detected active galactic nuclei (AGNs) at redshifts greater than 3, comprising the largest high-z X-ray-selected sample to date. The catalog includes rest-frame 2-10 keV luminosities and X-ray hardness ratios, with analysis confirming a decreasing comoving space density of AGNs with increasing redshift up to z ~ 7. It was created by NASA HEASARC in March 2016 based on data from the Chandra Cosmological Evolution Survey and Chandra Multi-wavelength Project.

Use Cases

• Analyze the distribution of rest-frame 2-10 keV luminosities (log L_X) across 209 AGNs to study high-redshift AGN power.
• Investigate the correlation between X-ray hardness ratios and optical classifications to understand AGN obscuration, noting ~26% of objects have mismatched classifications.
• Utilize the 1/V_max method on the sample to model the comoving space density evolution of AGNs above z > 3.
• Compare the comoving space density of type-1 and type-2 AGNs at z > 3 to test luminosity-dependent density evolution (LDDE) models.
• Study the properties of the 27 AGNs at z > 4 to validate source number counts in the 0.5-2 keV band against LDDE model expectations.

Strengths

• Contains 209 AGNs, representing the largest high-redshift (z > 3) X-ray-selected sample compiled at the time of publication.
• Provides detailed physical parameters including rest-frame 2-10 keV luminosities spanning log L_X = 43.3 - 46.0 erg/s and X-ray hardness ratios.
• Enables robust statistical analysis, with 27 AGNs at z > 4 used to constrain evolutionary models.

Limitations

• Sample size of 209 AGNs, while the largest for its type, may limit granular statistical analyses of rare sub-populations.
• Data is based on 2016 processing of earlier survey catalogs (C-COSMOS and ChaMP), so newer discoveries are not included.
• Relies on combined spectroscopic and photometric information from specific surveys, which may introduce selection biases.

Provenance

Source

NASA HEASARC, based on the CDS catalog J/MNRAS/445/1430.

Collection Method

Combined analysis of AGNs selected from the C-COSMOS X-ray catalog and the Chandra Multi-wavelength Project (ChaMP) catalog, using spectroscopic and photometric information.

Time Range

Observational data from the referenced Chandra surveys (publication dates 2011, 2012, 2006).

Freshness

Catalog created in March 2016; underlying data from surveys conducted prior.

Geography

Extragalactic; sources are active galactic nuclei at cosmological distances (redshift z > 3).