MIPS 24 {mu}m OBSERVATIONS OF THE HUBBLE DEEP FIELD SOUTH: PROBING THE IR-RADIO CORRELATION OF GALAXIES AT z>1
- Infrared Processing and Analysis Center, MS220-6, California Institute of Technology, Pasadena CA 91125 (United States)
- Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States)
- Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States)
- Department of Astronomy, Yale University, New Haven, CT 06520 (United States)
- Departmento de Astronomia y Astrofisica, Universidad Catolica de Chile, Santiago (Chile)
We present MIPS 24 {mu}m observations of the Hubble Deep Field South taken with the Spitzer Space Telescope. The resulting image is 254 arcmin{sup 2} in size and has a sensitivity ranging between {approx}12 and {approx}30 {mu}Jy rms, with a median sensitivity of {approx}20 {mu}Jy rms. A total of 495 sources have been cataloged with a signal-to-noise ratio greater than 5{sigma}. The source catalog is presented as well as source counts which have been corrected for completeness and flux boosting. The IR sources are then combined with MUSYC optical/NIR and ATHDFS radio observations to obtain redshifts and radio flux densities of the sample. We use the IR/radio flux density ratio (q{sub 24}) to explore the IR-radio correlation for this IR sample and find q{sub 24} = 0.71 {+-} 0.31 for sources detected in both IR and radio. The results are extended by stacking IR sources not detected in the radio observations and we derive an average q{sub 24} for redshift bins between 0 < z < 2.5. We find that the high-redshift (z>1) sources have an average q{sub 24} ratio which is better fit by local LIRG SEDs rather than local ULIRG SEDs, indicating that high-redshift ULIRGs differ in their IR/radio properties. So, ULIRGs at high-redshift have SEDs different from those found locally. Infrared-faint radio sources are examined, and while nine radio sources do not have an MIPS detection and are therefore radio-loud active galactic nuclei (AGNs), only one radio source has an extreme IRAC 3.6 {mu}m to radio flux density ratio indicating it is a radio-loud AGN at z>1.
- OSTI ID:
- 21471277
- Journal Information:
- Astrophysical Journal, Vol. 723, Issue 2; Other Information: DOI: 10.1088/0004-637X/723/2/1110; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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