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Deep spitzer observations of infrared-faint radio sources: High-redshift radio-loud active galactic nuclei?

journal contribution
posted on 2023-05-17, 09:54 authored by Norris, RP, Afonso, J, Cava, A, Farrah, D, Huynh, MT, Ivison, RJ, Jarvis, M, Lacy, M, Mao, M, Maraston, C, Mauduit, J-C, Middelberg, E, Oliver, S, Seymour, N, Surace, J
Infrared-faint radio sources (IFRSs) are a rare class of objects which are relatively bright at radio wavelengths but very faint at infrared and optical wavelengths. Here we present sensitive near-infrared observations of a sample of these sources taken as part of the Spitzer Extragalactic Representative Volume Survey. Nearly all the IFRSs are undetected at a level of ~1 ìJy in these new deep observations, and even the detections are consistent with confusion with unrelated galaxies. A stacked image implies that the median flux density is S3.6 ìm ~ 0.2 ìJy or less, giving extreme values of the radio-infrared flux density ratio. Comparison of these objects with known classes of object suggests that the majority are probably high-redshift radio-loud galaxies, possibly suffering from significant dust extinction.


Publication title

The Astrophysical Journal: An International Review of Astronomy and Astronomical Physics








School of Natural Sciences


Institute of Physics Publishing Inc

Place of publication

United States

Rights statement

Copyright 2011 American Astronomical Society

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Expanding knowledge in the physical sciences

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