J/ApJS/203/15 Counterparts to 1.4GHz sources in ECDF-S (Bonzini+, 2012)
The sub-mJy radio population of the E-CDFS: optical and infrared counterpart
identification.
Bonzini M., Mainieri V., Padovani P., Kellermann K.I., Miller N.,
Rosati P., Tozzi P., Vattakunnel S., Balestra I., Brandt W.N., Luo B.,
Xue Y.Q.
<Astrophys. J. Suppl. Ser., 203, 15 (2012)>
=2012ApJS..203...15B 2012ApJS..203...15B
ADC_Keywords: Radio sources ; Cross identifications ; X-ray sources ;
Redshifts ; Surveys ; Photometry, infrared ; Photometry, RI
Keywords: cosmology: observations - galaxies: active - galaxies: starburst -
radio continuum: galaxies
Abstract:
We study a sample of 883 sources detected in a deep Very Large Array
survey at 1.4GHz in the Extended Chandra Deep Field South. This paper
focuses on the identification of their optical and infrared (IR)
counterparts. We use a likelihood-ratio technique that is particularly
useful when dealing with deep optical images to minimize the number of
spurious associations. We find a reliable counterpart for 95% of our
radio sources. Most of the counterparts (74%) are detected at optical
wavelengths, but there is a significant fraction (21%) that are only
detectable in the IR. Combining newly acquired optical spectra with
data from the literature, we are able to assign a redshift to 81% of
the identified radio sources (37% spectroscopic). We also investigate
the X-ray properties of the radio sources using the Chandra 4Ms and
250ks observations. In particular, we use a stacking technique to
derive the average properties of radio objects undetected in the
Chandra images. The results of our analysis are collected in a new
catalog containing the position of the optical/IR counterpart, the
redshift information, and the X-ray fluxes. It is the deepest
multi-wavelength catalog of radio sources, which will be used for
future study of this galaxy population.
Description:
The E-CDFS was observed at 1.4GHz with the VLA between 2007 June and
September (Miller et al. 2008, Cat. J/ApJS/179/114). The mosaic image
covers an area of about 34x34arcmin with near-uniform sensitivity. The
second data release (N. Miller et al. 2012, in preparation) provides a
new source catalog with a 5σ point-source detection limit, for a
total of 883 sources. We assigned a progressive identification number
(RID) to the sources ordered by increasing right ascension.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 95 883 Radio information and identification process results
table5.dat 123 839 Main characteristics and redshift information
of the radio source counterparts
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See also:
II/261 : GOODS initial results (Giavalisco+, 2004)
J/ApJS/195/10 : The CDF-S survey: 4Ms source catalogs (Xue+, 2011)
J/ApJ/727/1 : IRAC/MUSYC SIMPLE survey (Damen+, 2011)
J/ApJS/191/124 : Opt. spectroscopy of ECDF-S X-ray sources (Silverman+, 2010)
J/ApJS/189/270 : MUSYC optical imaging in ECDF-S (Cardamone+, 2010)
J/A+A/511/A50 : JHks of GOODS-South field (Retzlaff+, 2010)
J/ApJ/693/1713 : Spectroscopy of X-ray sources in ECDF-S (Treister+, 2009)
J/ApJS/183/295 : A K-selected catalog of the ECDFS from MUSYC (Taylor+, 2009)
J/A+A/504/751 : GOODS-MUSIC catalog updated version (Santini+, 2009)
J/A+A/478/83 : GOODS-South Field VLT/FORS2 redshifts. III. (Vanzella+, 2008)
J/ApJS/179/114 : VLA 1.4GHz survey of E-CDF-S (Miller+, 2008)
J/A+A/465/1099 : Redshift catalog of 691 objects in CDFS (Ravikumar+, 2007)
J/AJ/132/2409 : Deep ATLAS radio observations of CDFS (Norris+, 2006)
J/A+A/456/881 : EIS: infrared deep public survey (Olsen+, 2006)
J/ApJS/161/21 : Extended Chandra Deep Field-South survey (Lehmer+, 2005)
J/ApJS/155/271 : CDF-S: Optical spectroscopy (Szokoly+, 2004)
J/A+A/428/1043 : Redshifts from VIMOS VLT Deep Survey (Le Fevre+, 2004)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- RID Radio source identification number
5 I1 h RAh [3] Radio Hour of Right Ascension (J2000)
7- 8 I2 min RAm [31/33] Radio Minute Right Ascension (J2000)
10- 14 F5.2 s RAs Radio Second of Right Ascension (J2000)
16 A1 --- DE- [-] Sign of the Radio Declination (J2000)
17- 18 I2 deg DEd [27/28] Radio Degree of Declination (J2000)
20- 21 I2 arcmin DEm Radio Arcminute of Declination (J2000)
23- 26 F4.1 arcsec DEs Radio Arcsecond of Declination (J2000)
28- 34 F7.1 uJy Sr [30.2/90450] Radio flux density at 1.4GHz
36- 40 F5.1 uJy e_Sr The 1σ error in Sr
42- 47 F6.1 --- S/N Signal-to-Noise
49 I1 h RACh ?=0 Counterpart Hour of Right Ascension (J2000)
51- 52 I2 min RACm ?=0 Counterpart Minute of Right Ascension (J2000)
54- 58 F5.2 s RACs ?=0 Counterpart Second of Right Ascension (J2000)
60 A1 --- DEC- [-] Sign of the Counterpart Declination (J2000)
61- 62 I2 deg DECd ?=0 Counterpart Degree of Declination (J2000)
64- 65 I2 arcmin DECm ?=0 Counterpart Arcminute of Declination (J2000)
67- 71 F5.2 arcsec DECs ?=0 Counterpart Arcsecond of Declination (J2000)
73- 77 F5.2 --- Rel [0.6/10]?=0 Reliability of the association (1)
79- 82 F4.1 arcsec Sep [0/2.3]?=99 Distance between radio and counterpart
84- 95 A12 --- CCat Counterpart catalog (2)
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Note (1): After a careful analysis, we decided to consider as reliable only
counterparts with reliability greater than 0.6. This threshold ensures
that the expected number of spurious associations is below 5% for each
auxiliary catalog. 9.00 = revisited association (see Section 3.4).
See Sections 3.2 and 3.5 for further explanations.
Note (2): Counterpart catalog, as in table 1, as follows:
24um-FIDEL = Spitzer/MIPS; Dickinson & FIDEL Team (2007AAS...211.5216D 2007AAS...211.5216D)
IRAC-SIMPLE = Spitzer/IRAC; Damen et al. (2011, Cat. J/ApJ/727/1)
Ks-MUSYC = CTIO 4m/ISPI; Taylor et al. (2009, Cat. J/ApJS/183/295;
<[TFV2009] ECDFS NNNNN> for Simbad)
Ks-ISAAC = ESO VLT/ISAAC; Retzlaff et al. (2010, Cat. J/A+A/511/A50)
H-SOFI = ESO NTT/SOFI; Olsen et al. (2006, Cat. J/A+A/456/881)
H-GNS = HST/NICMOS; Conselice et al. (2011MNRAS.413...80C 2011MNRAS.413...80C)
z-GOODS = HST/ACS; Dickinson et al. (2003mglh.conf..324D) and Giavalisco
et al. (2004, Cat. II/261; in Simbad)
R-WFI = ESO 2.2m/WFI; Giavalisco et al. (2004, Cat. II/261)
v-GEMS = HST/ACS; Rix et al. (2004ApJS..152..163R 2004ApJS..152..163R) and Caldwell et al.
(2008ApJS..174..136C 2008ApJS..174..136C)
U-VIMOS = ESO VLT/VIMOS; Nonino et al. (2009ApJS..183..244N 2009ApJS..183..244N)
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- RID Radio identification number
5- 9 F5.2 mag Rmag [16.23/26.77]?=0 WFI catalog (Cat. II/261)
R band AB magnitude
11- 15 F5.2 mag e_Rmag ?=0 Error in Rmag
17- 21 F5.2 mag Kmag [14.73/22.62]?=0 MUSYC catalog
(Cat. J/ApJS/183/295) KS band AB magnitude
23- 26 F4.2 mag e_Kmag ?=0 Error in Kmag
28- 32 F5.2 mag [3.6] ?=0 SIMPLE catalog (Cat. J/ApJ/727/1) 3.6 micron
band AB magnitude
34- 37 F4.2 mag e_[3.6] ?=0 Error in 3.6mag
39- 43 F5.2 --- z [0/6.99]?=99 Best redshift of counterpart (1)
45- 49 F5.2 --- zph ?=99 Photometric redshift
51- 55 F5.2 --- e_zph ?=99 Lower 68% uncertainty in zphot
57- 61 F5.2 --- E_zph ?=99 Upper 68% uncertainty in zphot
63- 68 A6 --- r_zph Reference for zphot (2)
70- 74 F5.2 mag zsp [0/4.5]?=99 Spectroscopic redshift
76 I1 --- q_zsp ?=0 Quality flag, 3=secure (3)
78- 82 A5 --- r_zsp Reference for zspec (4)
84- 91 E8.2 mW/m2 Soft ? Soft X-ray (0.5-2keV) band flux; erg/s/cm2
93-100 E8.2 mW/m2 e_Soft ? Error in Soft
102-109 E8.2 mW/m2 Hard ? Hard X-ray (2-10keV) band flux; erg/s/cm2
111-118 E8.2 mW/m2 e_Hard ? Error in Hard
120-123 I4 --- XID ? X-ray identifier (5)
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Note (1): The best redshift is spectroscopic if q_zsp≥2, photometric otherwise.
Note (2): Reference as follows:
ZEB_pz = Rafferty et al. (2011ApJ...742....3R 2011ApJ...742....3R);
C10_pz = Cardamone et al. (2010, cat. J/ApJS/189/270);
S09_pz = Santini et al. (2009, Cat. J/A+A/504/751);
KM_pz = Taylor et al. (2009, Cat. J/ApJS/183/295).
Note (3): Quality flag as follows:
3 = secure redshift;
2 = reasonable redshift;
1 = one line detection or tentative redshift.
Note (4): References for spectroscopic redshift, as in table 4, as follows:
FORS = FORS2; Vanzella et al. 2008, Cat. J/A+A/478/83
GMASS = FORS2; Kurk et al. (2012arXiv1209.1561K 2012arXiv1209.1561K)
K07 = Keck (N=32 zspec adopted); Silverman et al. 2010, Cat. J/ApJS/191/124
K08 = Keck (N=18 zspec adopted); Silverman et al. 2010, Cat. J/ApJS/191/124
N06 = 2dF; Norris et al. (2006, Cat. J/AJ/132/2409)
P80 = VIMOS; Silverman et al. 2010, Cat. J/ApJS/191/124
P81 = VIMOS; this work
R07 = VIMOS; Ravikumar et al. 2007, Cat. J/A+A/465/1099
S04 = FORS1/FORS2 (N=38 zspec adopted); Szokoly et al. 2004,
Cat. J/ApJS/155/271
S04F = FORS1/FORS2 (N=1 zspec adopted); Szokoly et al. 2004,
Cat. J/ApJS/155/271
T09 = VIMOS; Treister et al. 2009, Cat. J/ApJ/693/1713
VJB = VIMOS; Silverman et al. 2010, Cat. J/ApJS/191/124
VLR = VIMOS-LR; Balestra et al. 2010, Cat. J/A+A/512/A1
VMR = VIMOS-MR; Balestra et al. 2010, Cat. J/A+A/512/A1
VVDS = VIMOS; Le Fevre et al. 2004, Cat. J/A+A/428/1043
Note (5): Source of XID:
* XID<1000: from Xue et al. 2011, Cat. J/ApJS/195/10;
<[XLB2011] JHHMMSS.ss+DDMMSS.s> in Simbad.
* XID>1000: from Lehmer et al. 2005, Cat. J/ApJS/161/21;
<[LBA2005] NNN> in Simbad, where "NNN" is XID-1000.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 04-Dec-2012