DEEP SPITZER OBSERVATIONS OF INFRARED-FAINT RADIO SOURCES: HIGH-REDSHIFT RADIO-LOUD ACTIVE GALACTIC NUCLEI?

Journal Article · Wed Jul 20 00:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/736/1/55· OSTI ID:21578298

Norris, Ray P; Mao, Minnie ^[1]; Afonso, Jose ^[2]; Cava, Antonio ^[3]; Farrah, Duncan; Oliver, Seb ^[4]; Huynh, Minh T; Mauduit, Jean-Christophe; Surace, Jason ^[5]; Ivison, R J ^[6]; Jarvis, Matt ^[7]; Lacy, Mark ^[8]; Maraston, Claudia ^[9]; Middelberg, Enno ^[10]; Seymour, Nick ^[11]

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1. CSIRO Australia Telescope National Facility, P.O. Box 76, Epping, NSW, 1710 (Australia)
2. Observatorio Astronomico de Lisboa, Faculdade de Ciencias, Universidade de Lisboa, Tapada da Ajuda, 1349-018 Lisbon (Portugal)
3. Departamento de Astrofisica, Facultad de CC. Fisicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain)
4. Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom)
5. Infrared Processing and Analysis Center, MS220-6, California Institute of Technology, Pasadena, CA 91125 (United States)
6. UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)
7. Centre for Astrophysics, Science and Technology Research Institute, University of Hertfordshire, Hatfield, Herts, AL10 9AB (United Kingdom)
8. NRAO, 520 Edgemont Road, Charlottesville, VA 22903 (United States)
9. Institute of Cosmology and Gravitation, Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX (United Kingdom)
10. Astronomisches Institut, Ruhr-Universitaet Bochum, Universitaetsstr. 150, 44801 Bochum (Germany)
11. Mullard Space Science Laboratory, UCL, Holmbury St Mary, Dorking, Surrey, RH5 6NT (United Kingdom)

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 {approx}1 {mu}Jy 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 S{sub 3.6{mu}m} {approx} 0.2 {mu}Jy 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.

• OSTI ID: 21578298
• Journal Information: Astrophysical Journal, Vol. 736, Issue 1; Other Information: DOI: 10.1088/0004-637X/736/1/55; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
FLUX DENSITY
GALACTIC EVOLUTION
GALAXY NUCLEI
NEAR INFRARED RADIATION
RADIOWAVE RADIATION
RED SHIFT
ELECTROMAGNETIC RADIATION
EVOLUTION
INFRARED RADIATION
RADIATIONS