J/ApJ/714/1689 DRAO ELAIS N1 catalog (Grant+, 2010)
The DRAO Planck Deep Fields: the polarization properties of radio galaxies at
1.4 GHz.
Grant J.K., Taylor A.R., Stil J.M., Landecker T.L., Kothes R., Ransom R.R.,
Scott D.
<Astrophys. J., 714, 1689-1701 (2010)>
=2010ApJ...714.1689G 2010ApJ...714.1689G
ADC_Keywords: Galaxies, radio ; Polarization ; Radio continuum
Keywords: galaxies: evolution - galaxies: individual (ELAIS N1) -
galaxies: magnetic fields - polarization - radio continuum: galaxies -
techniques: polarimetric
Abstract:
We present results of deep polarization imaging at 1.4GHz with the
Dominion Radio Astrophysical Observatory as part of the DRAO Planck
Deep Fields project. This deep extragalactic field covers 15.16deg2
centered at RA(J2000)=16:14 and DE(J2000)=54:56, has an angular
resolution of 42"x62" at the field center, and reaches a sensitivity
of 55uJy/beam in Stokes I and 45uJy/beam in Stokes Q and U. We detect
958 radio sources in Stokes I of which 136 are detected in
polarization. We present the Euclidean-normalized polarized
differential source counts down to 400uJy. These counts indicate that
sources have a higher degree of fractional polarization at fainter
Stokes I flux density levels than for brighter sources, confirming an
earlier result. We find that the majority of our polarized sources are
steep-spectrum objects with a mean spectral index of -0.77, and there
is no correlation between fractional polarization and spectral index.
We also matched deep field sources to counterparts in the Faint Images
of the Radio Sky at Twenty Centimeters catalog. Of the polarized
sources, 77% show structure at the arcsecond scale whereas only 38% of
the sources with no detectable polarization show such structure. The
median fractional polarization for resolved sources is 6.8%, while it
is 4.4% for compact objects. The polarized radio sources in our deep
field are predominantly those sources which are resolved and show the
highest degrees of fractional polarization, indicating that the lobe
dominated structure may be the source of the highly polarized sources.
These resolved radio galaxies dominate the polarized source counts at
P0=(Q2+U2)0.5<3mJy.
Description:
The DRAO ST was used to produce a deep polarization mosaic at 1.4GHz
centered on the ELAIS N1 field (Oliver et al. 2000MNRAS.316..749O 2000MNRAS.316..749O),
expanding upon pilot observations reported by Taylor et al. (2007,
Cat. J/ApJ/666/201) in both solid angle and sensitivity. The DRAO ST
simultaneously observed the HI 21cm line and 408MHz continuum along
with 1.4GHz continuum. The observations of the DRAO ELAIS N1 deep
field began in 2004 August and the final deep field observation was
completed in 2008 July.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 117 136 Polarized sources from the DRAO ELAIS N1 source
catalog
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See also:
II/255 : SWIRE ELAIS N1 Source Catalogs (Surace+, 2004)
VIII/71 : The FIRST Survey Catalog, Version 03Apr11 (Becker+ 2003)
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
VIII/62 : The Westerbork Northern Sky Survey (Leiden, 1998)
J/MNRAS/405/2243 : GMOS/WIYN spectroscopic catalogue (Trichas+, 2010)
J/MNRAS/395/269 : ELAIS-N1 field 325MHz observations (Sirothia+, 2009)
J/MNRAS/383/75 : Deep 610MHz survey of ELAIS-N1 sources (Garn+, 2008)
J/ApJ/666/201 : Radio polarimetry of the ELAIS N1 field (Taylor+, 2007)
J/MNRAS/371/1891 : GOODS ELAIS-N1 24um flux densities (Rodighiero+, 2006)
J/MNRAS/358/333 : ELAIS optical ident. at 15um + 1.4GHz (Gonzalez-Solares+,
2005)
J/AJ/129/1198 : SDSS quasars in SWIRE ELAIS N1 field (Hatziminaoglou+, 2005)
J/MNRAS/343/293 : ELAIS deep X-ray survey. I. (Manners+, 2003)
J/MNRAS/302/222 : ISO ELAIS 20cm VLA survey regions (Ciliegi+, 1999)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- --- [DRAO_]
6- 25 A20 --- DRAO Source name (JHHMMSS.ss+DDMMSS.ss)
27- 28 I2 h RAh Hour of right ascension (J2000)
30- 31 I2 min RAm Minute of right ascension (J2000)
33- 37 F5.2 s RAs Second of right ascension (J2000)
39- 42 F4.2 s e_RAs RAs uncertainty
44 A1 --- DE- Sign of declination (J2000)
45- 46 I2 deg DEd Degree of declination (J2000)
48- 49 I2 arcmin DEm Arcminute of declination (J2000)
51- 55 F5.2 arcsec DEs Arcsecond of declination (J2000)
57- 61 F5.2 arcsec e_DEs DEs uncertainty
63- 68 F6.2 mJy S 1.4GHz peak flux density
70- 73 F4.2 mJy e_S S uncertainty
75- 79 F5.2 mJy P0 Simmons & Stewart (1985A&A...142..100S 1985A&A...142..100S)
bias-corrected peak flux density P0 (1.4GHz)
81- 84 F4.2 mJy e_P0 P0 uncertainty
86- 90 F5.2 % Pol Percentage polarization (Π0)
92- 96 F5.2 % e_Pol Pol uncertainty
98-103 F6.2 deg PA [-86/85] Polarization angle (1)
105 A1 --- l_alpha Limit flag on alpha
106-110 F5.2 --- alpha Spectral index α1420-325 (2)
112-115 F4.2 --- e_alpha ? alpha uncertainty
117 A1 --- Cl [RC ]? Resolved or Compact FIRST source (3)
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Note (1): Polarization angle, P.A.=0.5arctan(U/Q) measured in the J2000
coordinate system.
Note (2): Spectral index α1420-325MHz calculated between our
flux density averaged over all four frequency bands and the
WENSS (Cat. VIII/62) source catalog (see Section 3.4).
Note (3): Classification from FIRST (Cat. VIII/71):
R = Resolved FIRST radio source. There are multiple FIRST sources within 1'
corresponding to one DRAO source but these multiple FIRST sources are a
single multi-component radio source, where the two lobes and central
component are each clearly identified. In these cases, the DRAO source
position is matched to the position of the central component and
classified as a resolved FIRST radio source.
C = Compact FIRST source. A DRAO source is classified as a compact FIRST
source in cases where there is only one compact FIRST source
corresponding to one DRAO source.
See section 3.3 and Figure 14 for further details.
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 25-Apr-2012