WISE Mid-Infrared Properties of compact Active Galactic Nuclei selected from the high-radio-frequency AT20G Survey
arXiv:2002.07429 · doi:10.1093/mnras/staa513
Abstract
Past studies of compact active galactic nuclei (AGNs), the dominant population at high radio frequencies, selected them using flat spectral index criteria. This biases the sample due to the steepening of AGN spectra at high radio frequencies. We improve upon this by selecting 3610 compact AGNs using their angular size information (0.15 arcsec scale) from the Australia Telescope 20 GHz (AT20G) high-angular-resolution catalogue. We cross-match these against the Wide-field Infrared Survey Explorer All-WISE catalogue and present a catalogue with 3300 (91%) matches, 91 (3%) rejects and 219 (6%) nondetections that are excellent high redshift candidates. Of the matched compact AGNs, 92% exhibit QSO mid-infrared colours (W1-W2>0.5). Therefore, our sample of high frequency compact sources has a very high rate of identification with mid-infrared QSOs. We find counterparts for 88% of 387 compact steep-spectrum (CSS) sources in the AT20G survey, 82%5% of which exhibit QSO mid-infrared colours and have moderate redshifts (median redshift = 0.82), while those dominated by host galaxy colours in mid-infrared have lower redshifts (median redshift = 0.13). The latter classified into late- and early-type galaxies using their mid-infrared colours shows a majority (68%4%) have colours characteristic of late-type galaxies. Thus, we find that a larger fraction of these CSS sources are embedded in hosts with higher gas densities than average early-type galaxies. We compare mid-infrared colours of our AGNs against those reported for AGNs primarily selected using non-radio techniques. This shows that mid-infrared SED of high frequency selected compact radio AGN is comparatively less red, possibly due to contributions from their hosts.
arXiv commentAccepted for publication in MNRAS. 21 pages, 18 figures
References in corpus (31)
- The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
- Unified Schemes for Radio-Loud Active Galactic Nuclei
- Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Power Spectra and WMAP-Derived Parameters
- The Co-Evolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe
- Spectral Energy Distributions and Multiwavelength Selection of Type 1 Quasars
- The 6dF Galaxy Survey: Final Redshift Release (DR3) and Southern Large-Scale Structures
- The Sloan Digital Sky Survey Quasar Catalog V. Seventh Data Release
- SUMSS: A Wide-Field Radio Imaging Survey of the Southern Sky. II. The Source Catalogue
- Mid-Infrared Selection of AGN with the Wide-Field Infrared Survey Explorer. I. Characterizing WISE-Selected AGN in COSMOS
- The SuperCOSMOS Sky Survey. Paper I: Introduction and Description
- Photometric redshift and classification for the XMM-COSMOS sources
- The Australia Telescope 20 GHz Survey: The Source Catalogue
- Using the Bright Ultra-Hard XMM-Newton Survey to define an IR selection of luminous AGN based on WISE colours
- Low Resolution Spectral Templates For AGNs and Galaxies From 0.03 -- 30 microns
- Predictions for high-frequency radio surveys of extragalactic sources
- The New Generation Atlas of Quasar Spectral Energy Distributions from Radio to X-rays
- Mean Spectral Energy Distributions and Bolometric Corrections for Luminous Quasars
- A pilot study of the radio-emitting AGN population: the emerging new class of FR0 radio-galaxies
- The local radio-galaxy population at 20 GHz
- Galaxy and Mass Assembly (GAMA): Exploring the WISE Cosmic Web in G12
- Discovery of a Population of Bulgeless Galaxies with Extremely Red Mid-IR Colors: Obscured AGN Activity in the Low Mass Regime?
- Mid-Infrared Colors of Dwarf Galaxies: Young Starbursts Mimicking Active Galactic Nuclei
- The Australia Telescope 20GHz (AT20G) Survey: analysis of the extragalactic source sample
- Discovery of a radio galaxy at z = 5.72
- New Insights on the z-alpha Correlation from Complete Radio Samples
- Optical Properties of High-Frequency Radio Sources from the Australia Telescope 20 GHz (AT20G) Survey
- The Large Area Radio Galaxy Evolution Spectroscopic Survey (LARGESS): Survey design, data catalogue and GAMA/WiggleZ spectroscopy
- Composite Spectral Energy Distributions and Infrared-Optical Colors of Type 1 and Type 2 Quasars
- The Planck-ATCA Co-eval Observations (PACO) project: the bright sample
- The AT20G high angular resolution catalogue
- Spectral Properties and the Effect on Redshift Cut-off of Compact AGNs from the AT20G Survey