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Radio Polarimetry of the ELAIS N1 Field: Polarized Compact Sources

Taylor, A. R. and Stil, J. M. and Grant, J. K. and Landecker, T. L. and Kothes, R. and Reid, R. I. and Gray, A. D. and Scott, Douglas and Martin, P. G. and Boothroyd, A. I. and Joncas, G. and Lockman, Felix J. and English, J. and Sajina, A. and Bond, J. R. (2007) Radio Polarimetry of the ELAIS N1 Field: Polarized Compact Sources. Astrophysical Journal, 666 (1). pp. 201-211. ISSN 0004-637X.

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We present deep polarimetric observations at 1420 MHz of the European Large Area ISO Survey North 1 region (ELAIS N1) as part of the Dominion Radio Astrophysical Observatory Planck Deep Fields project. By combining closely spaced aperture synthesis fields, we image a region of 7.43 deg^2 to a maximum sensitivity in Stokes Q and U of 78 μJy beam^(-1), and detect 786 compact sources in Stokes I. Of these, 83 exhibit polarized emission. We find that the differential source counts (log N-log p) for polarized sources are nearly constant down to p > 500 μJy, and that these faint polarized radio sources are more highly polarized than the strong source population. The median fractional polarization is 4.8% ± 0.7% for polarized sources with Stokes I flux density between 10 and 30 mJy, approximately 3 times larger than sources with I > 100 mJy. The majority of the polarized sources have been identified with galaxies in the Spitzer Wide Area Infrared Extragalactic Survey (SWIRE) image of ELAIS N1. Most of the galaxies occupy regions in the IRAC 5.8 μm/3.6 μm versus 8.0 μm/4.5 μm color-color diagram associated with dusty AGNs, or with ellipticals with an aging stellar population. A few host galaxies have colors that suggests significant PAH emission in the near-infrared. A small fraction, 12%, of the polarized sources are not detected in the SWIRE data. None of the polarized sources in our sample appears to be associated with an actively star-forming galaxy.

Item Type:Article
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URLURL TypeDescription
Scott, Douglas0000-0002-6878-9840
Martin, P. G.0000-0002-5236-3896
Sajina, A.0000-0002-1917-1200
Additional Information:© 2007 American Astronomical Society. Print publication: Issue 1 (2007 September 1); received 2007 February 27; accepted for publication 2007 May 11. Observations and research on the DRAO Planck Deep Fields are supported by the Natural Sciences and Engineering Research Council of Canada and the National Research Council Canada. Ev Sheehan of DRAO was instrumental in improving the sensitivity of the DRAO Synthesis Telescope, with the outcome recorded in this paper. We are indebted to him for his skill and dedication to this difficult task. The Dominion Radio Astrophysical Observatory is operated as a National Facility by the National Research Council of Canada.
Funding AgencyGrant Number
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
National Research Council of CanadaUNSPECIFIED
Subject Keywords:galaxies: evolution; galaxies: individual (ELAIS N1); polarization; radio continuum: galaxies; techniques: polarimetric
Issue or Number:1
Record Number:CaltechAUTHORS:20091204-110302504
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Official Citation:Radio Polarimetry of the ELAIS N1 Field: Polarized Compact Sources A. R. Taylor, J. M. Stil, J. K. Grant, T. L. Landecker, R. Kothes, R. I. Reid, A. D. Gray, Douglas Scott, P. G. Martin, A. I. Boothroyd, G. Joncas, Felix J. Lockman, J. English, A. Sajina, and J. R. Bond 2007 ApJ 666 201-211 doi: 10.1086/519786
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:16876
Deposited By: Jason Perez
Deposited On:04 Dec 2009 22:04
Last Modified:09 Mar 2020 13:19

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