SWBATAGN60 - Swift BAT 60-Month Survey of Active Galactic Nuclei Catalog

Overview

Surveys above 10 keV represent one of the best resources to provide an unbiased census of the population of active galactic nuclei (AGNs). The authors present the results of 60 months of observation from 2005 March to 2010 March of the hard X-ray sky with the Swift Burst Alert Telescope (BAT). In this time frame, BAT detected (in the 15 - 55 keV band) 720 sources with a signal-to-noise ratio of >= 5 sigma in an all-sky survey, of which 428 are associated with AGNs, most of which are nearby. This sample has negligible incompleteness and statistics which are a factor of ~ 2 larger over similarly complete sets of AGNs. The sample contains (at least) 15 bona fide Compton-thick AGNs and 3 likely candidates. Compton-thick AGNs represent ~ 5% of AGN samples detected above 15 keV. The authors use the BAT data set to refine the determination of the log N - log S of AGNs which is extremely important, now that NuSTAR prepares for launch, toward assessing the AGN contribution to the cosmic X-ray background. The authors show that the log N - log S of AGNs selected above 10 keV is now established to ~ 10% precision. They derive the luminosity function of Compton-thick AGNs and measure a space density of 7.9 (+4.1, -2.9) x 10^-5 Mpc^-3 for objects with a de-absorbed luminosity larger than 2 x 10⁴² erg s^-1. As the BAT AGNs are all mostly local, they allow us to investigate the spatial distribution of AGNs in the nearby universe regardless of absorption. The authors find concentrations of AGNs that coincide spatially with the largest congregations of matter in the local (<= 85 Mpc) universe. There is some evidence that the fraction of Seyfert 2 objects is larger than average in the direction of these dense regions.

Catalog Bibcode

2012ApJ...749...21A

References

The 60-month All-Sky Burst Alert Telescope Survey of Active Galactic Nuclei
and the Anisotropy of Nearby AGNs
    Ajello M., Alexander D.M., Greiner J., Madejski G.M., Gehrels N.,
    Burlon D.
    <Astrophysical Journal, 749, 21 (2012)>
    =2012ApJ...749...21A

Provenance

This table was created by the HEASARC in May 2012, based on an electronic version of Table 1 from the referenced paper, which was obtained from the ApJ website.

Parameters

Name
The Swift BAT source designation using the J2000.0 equatorial coordinates truncated to 0.1 minutes of time in RA and 1 arcminute in Dec.

RA
The Right Ascension of the Swift BAT source in the selected equinox. This was given in J2000 decimal degrees to a precision of 0.001 degrees (3.6 arcseconds) in the original table.

Dec
The Declination of the Swift BAT source in the selected equinox. This was given in J2000 decimal degrees to a precision of 0.001 degrees (3.6 arcseconds) in the original table.

LII
The Galactic Longitude of the Swift BAT source.

BII
The Galactic Latitude of the Swift BAT source.

Error_Radius
The positional error of the Swift BAT source, in arcseconds. This was converted by the HEASARC from the units of arcminutes given in the original table.

Flux
The observed flux of the Swift BAT source in the 15 to 55 keV energy interval, in erg/s/cm².

SNR
The signal-to-noise ratio of the Swift BAT source. The selected sources are all >= 5 sigma.

Alt_Name
The Swift BAT source identification obtained by the authors from cross-correlating their catalog with the catalogs listed in Section 2 of the reference paper.

AGN_Type
The source type of AGN using the following schema (where sources classed as AGNs lack an exact optical classification):

     AGN type   Meaning

     BLAZAR
     GiP        Galaxy in Pair of Galaxies
     LINER
     QSO
     RG         Radio Galaxy
     Sy         Seyfert

Redshift
The redshift of the Swift BAT source.

Photon_Index
The power-law photon index, Gamma, of the Swift BAT source in the 15 to 55 keV band.

Photon_Index_Error
The uncertainty in the power-law photon index, Gamma, of the Swift BAT source.

Log_Lx
The logarithm of the k-corrected X-ray luminosity of the Swift BAT source, in erg/s, computed according to equation (1) in the reference paper and assuming a standard concordance cosmology with H₀ = 71 km s^-1 Mpc^-1, Omega_M = 1 - Omega_Lambda = 0.27.

Class
The HEASARC Browse object classification based on the value of the agn_type parameter.

Contact Person

Questions regarding the SWBATAGN60 database table can be addressed to the HEASARC Help Desk.

Page Author: Browse Software Development Team
Last Modified: Monday, 16-Sep-2024 17:35:25 EDT