J/MNRAS/370/1034 FIRST-APM-SDSS survey for high-z radio QSOs (Carballo+, 2006)
A FIRST-APM-SDSS survey for high-redshift radio QSOs.
Carballo R., Gonzalez-Serrano J.I., Montenegro-Montes F.M., Benn C.R.,
Mack K.-H., Pedani M., Vigotti M.
<Mon. Not. R. Astron. Soc., 370, 1034-1045 (2006)>
=2006MNRAS.370.1034C 2006MNRAS.370.1034C
ADC_Keywords: QSOs ; Radio sources ; Photometry, photographic
Keywords: surveys - galaxies: high-redshift - quasars: general -
early Universe - radio continuum: galaxies
Abstract:
We selected from the VLA FIRST survey a sample of 94 objects with
star-like counterparts in the Sloan Digital Sky Survey (SDSS), and
with APM POSS-I colour O-E≥2, i.e. consistent with their being
high-redshift quasars. 78 of the 94 candidates can be classified
spectroscopically on the basis of either published data (mainly SDSS)
or the observations presented here. The fractions of QSOs (51 out of
78) and redshift z>3 QSOs (23 out of 78, 29 per cent) are comparable
to those found in other photometric searches for high-redshift QSOs.
We confirm that selecting colour O-E≥2 ensures inclusion of all QSOs
with 3.7≤z≤4.4. The fraction of 2≤z≤4.4 QSOs with broad absorption
lines (BALs) is 27±10 per cent (7/26) and the estimated BAL fraction
for radio-loud QSOs is at least as high as for optically selected QSOs
(∼13 per cent). Both the high BAL fraction and the high fraction of
low-ionization BALs among BALs (four to five out of seven) in our
sample, compared to previous work, are likely due to the red colour
selection O-E≥2.
Description:
Spectra of 11 candidates (indicated in column 9 of Table 2) were
obtained with the TNG on 2005 March 10 and 11 using the DOLORES
(Device Optimized for LOw RESolution) spectrograph in long-slit mode.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 86 94 Radio/optical properties and spectroscopic
classification of the 94 candidates
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See also:
VIII/71 : The FIRST Survey Catalog, Version 03Apr11 (Becker+ 2003)
J/ApJS/143/1 : FIRST-APM Source Catalog (McMahon+, 2002)
http://www.sdss.org : SDSS Home Page
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh SDSS Right ascension (J2000)
4- 5 I2 min RAm SDSS Right ascension (J2000)
7- 11 F5.2 s RAs SDSS Right ascension (J2000)
13 A1 --- DE- SDSS Declination sign (J2000)
14- 15 I2 deg DEd SDSS Declination (J2000)
17- 18 I2 arcmin DEm SDSS Declination (J2000)
20- 23 F4.1 arcsec DEs SDSS Declination (J2000)
25- 28 F4.2 arcsec Sep Radio-optical (FIRST-SDSS) separation
30- 35 F6.2 mJy S1.4GHz FIRST Flux density at 1.4GHz
(integrated for S1.4GHz>10mJy, otherwise peak)
37- 41 F5.3 mag E(B-V) Galactic extinction
(Schlegel et al., 1998ApJ...500..525S 1998ApJ...500..525S)
43- 47 F5.2 mag Emag E magnitude from McMahon et al.
(2002, Cat. J/ApJS/143/1)
49 A1 --- l_O-E Limit flag on O-E
50- 53 F4.2 mag O-E O-E colour index from McMahon et al.
(2002, Cat. J/ApJS/143/1) (1)
55- 57 A3 --- Rel [DR3 DR4] SDSS Source of spectrum, spectroscopic
classification, and redshift
59 I1 --- r_Sp [1/8]? Other Source of spectrum, spectroscopic
classification, and redshift (2)
61- 75 A15 --- Sp Spectroscopic classification
77- 82 F6.4 --- z ? Redshift
84- 86 A3 --- Rem Remarks (3)
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Note (1): FIRST optical identification catalogue (APM magnitudes recalibrated
with respect to APS, for more accurate photometry), and corrected for
Galactic reddening assuming AE=2.7E(B-V) and AO=4.4E(B-V)
(see White et al. 2000, Cat. J/ApJS/126/133)
Note (2): The references from the literature are as follows:
3 = This paper
1 = Benn et al. (2002MNRAS.329..221B 2002MNRAS.329..221B) Paper I
2 = Holt et al. (2004, Cat. J/MNRAS/348/857) Paper II
4 = Snellen et al. (2001MNRAS.325.1167S 2001MNRAS.325.1167S)
5 = Kopylov et al. (2004, Cat. J/A+A/421/455)
6 = Peroux et al. (2001AJ....121.1799P 2001AJ....121.1799P)
7 = Storrie-Lombardi et al. (1996ApJ...468..121S 1996ApJ...468..121S)
8 = Najita et al. (2000AJ....120.2859N 2000AJ....120.2859N)
Note (3): Notes are as follows:
a = Not a QSO in the 'DR3 Quasar Catalogue', probably because it does
not meet the requirement Mi>-22
(H0=70km/s/Mpc, OmegaM=0.3 and OmegaLambda=0.7)
b = classified in this work from the presence of C III] and Mg II
emission lines in the SDSS DR3 spectrum
c = spectrum not published
d = the source is not included in McMahon et al. (2002,
Cat. J/ApJS/143/1), therefore the APM calibration was adopted
e = spectrum not available on the SDSS web site
f = see Section 4.5
g = classified as a galaxy in 2MASS
(Kleinmann et al., 1994, Ap&SS 217, 11)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 23-Feb-2007