Evidence for Infrared-Faint Radio Sources as z > 1 Radio-Loud AGN

TL;DR

This study provides evidence that Infrared-Faint Radio Sources are likely high-redshift (z > 1) radio-loud AGN, based on deep infrared imaging and spectral energy distribution modeling.

Contribution

The paper presents the first detections of IFRS in deep IRAC images and constrains their nature as high-redshift AGN through detailed SED analysis.

Findings

Two IFRS sources detected in IRAC images.

Non-detections constrain source types.

SED modeling indicates z > 1 AGN.

Abstract

Infrared-Faint Radio Sources (IFRSs) are a class of radio objects found in the Australia Telescope Large Area Survey (ATLAS) which have no observable mid-infrared counterpart in the Spitzer Wide-area Infrared Extragalactic (SWIRE) survey. The extended Chandra Deep Field South now has even deeper Spitzer imaging (3.6 to 70 micron) from a number of Legacy surveys. We report the detections of two IFRS sources in IRAC images. The non-detection of two other IFRSs allows us to constrain the source type. Detailed modeling of the SED of these objects shows that they are consistent with high redshift (z > 1) AGN.