J/AJ/128/1002 SDSS candidate type II quasars. II (Zakamska+, 2004)
Candidate type II quasars from the Sloan Digital Sky Survey.
II. From radio to x-rays.
Zakamska N.L., Strauss M.A., Heckman T.M., Ivezic Z., Krolik J.H.
<Astron. J., 128, 1002-1016 (2004)>
=2004AJ....128.1002Z 2004AJ....128.1002Z
ADC_Keywords: Active gal. nuclei ; QSOs ; Galaxies, IR ; Galaxies, radio ;
X-ray sources ; Redshifts
Keywords: galaxies: active - infrared: galaxies - quasars: general - surveys -
X-rays: galaxies
Abstract:
Type II quasars are luminous active galactic nuclei (AGNs) whose
central engines and broad-line regions are obscured by intervening
material; such objects only recently have been discovered in
appreciable numbers. We study the multiwavelength properties of 291
type II AGN candidates (0.3<z<0.8) selected on the basis of their
optical emission-line properties from the spectroscopic database of
the Sloan Digital Sky Survey (Cat. J/AJ/126/2579). This sample
includes about 150 objects luminous enough to be classified as type II
quasars. We matched the sample to the FIRST (20cm, Cat.VIII/71),
IRAS (12-100µm, Cat. II/125), 2MASS (JHKs, Cat. II/246), and
RASS (0.1-2.4keV, Cat. IX/29) surveys. Roughly 10% of optically
selected type II AGN candidates are radio-loud, comparable to the AGN
population as a whole. About 40 objects are detected by IRAS at 60
and/or 100µm, and the inferred mid/far-IR luminosities lie in the
range L=1045-3x1046ergs/s. Average IR-to-[OIII]λ5007 ratios
of objects in our sample are consistent with those of other AGNs.
Objects from our sample are 10 times less likely to have soft X-ray
counterparts in RASS than type I AGNs with the same redshifts and
[OIII]λ5007 luminosities. The few type II AGN candidates from
our sample that are detected by RASS have harder X-ray spectra than
those of type I AGNs. The multiwavelength properties of the type II
AGN candidates from our sample are consistent with their
interpretation as powerful obscured AGNs.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 63 143 FIRST Matches of Type II AGNs
table2.dat 69 5 Radio Matches of Type II AGNs Not Covered by FIRST
table3.dat 64 74 IRAS Counterparts of Type II AGNs
table4.dat 72 6 RASS Counterparts of Type II AGNs
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See also:
J/AJ/126/2125 : SDSS candidate type II quasars (Zakamska+, 2003)
J/AJ/123/567 : SDSS quasar catalog, I: Early Data Release (Schneider+, 2002)
J/AJ/126/2579 : SDSS quasar catalog. II. First data release (Schneider+, 2003)
VIII/71 : The FIRST Survey Catalog, Version 03Apr11 (Becker+ 2003)
II/125 : IRAS catalogue of Point Sources, Version 2.0 (IPAC 1986)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
IX/10 : ROSAT All-Sky Bright Source Catalogue (1RXS)
IX/29 : ROSAT All-Sky Survey Faint Source Catalog (Voges+ 2000)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [SDSS]
6- 24 A19 --- SDSS SDSS Name, based on J2000.0 position (G1)
26- 30 F5.3 --- z Redshift
32- 36 F5.2 [solLum] logLum Log of [OIII]λ(5007) luminosity in
solar units
38- 43 F6.1 mJy F20cmc FIRST (20cm) core flux (1.5GHz)
45- 50 F6.1 mJy F20cmt 20cm total flux
52- 55 F4.1 --- Sp+Index ? Spectral index
57 I1 --- Morph [1/2] Morphology code (1)
59- 62 A4 --- Ref References (2)
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Note (1): The morphology code is defined as follows:
1 = Unresolved by FIRST (Cat. VIII/71) and NVSS (Cat. VIII/65);
2 = Resolved by FIRST (Cat. VIII/71) or NVSS (Cat. VIII/65).
Note (2): References:
1 = Condon et al. 1998, Cat. VIII/65 (NVSS)--if this reference is listed
it means that the total flux was taken from the NVSS;
2 = Gregory et al. 1996, Cat. VIII/40 (GB6);
3 = Rengelink et al. 1997, Cat. J/A+AS/124/259 (WENSS);
4 = Other (NED).
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [SDSS]
6- 24 A19 --- SDSS SDSS Name, based on J2000.0 position (G1)
27- 31 F5.3 --- z Redshift
34- 37 F4.2 [solLum] logLum Log of [OIII]λ(5007) luminosity in
solar units
40- 42 F3.1 arcmin Offset Offset between the optical and radio position
45- 49 F5.1 mJy F1.4GHz Flux density at 1.4GHz
51- 54 F4.1 --- Sp+Index ? Spectral Index
57 I1 --- Morph [1/2] Morphology code (1)
60- 69 A10 --- Ref References (2)
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Note (1): The morphology code is based on the NVSS (Cat. VIII/65)
images and defined as follows:
1 = a point source;
2 = an extended source.
Note (2): References:
1 = Condon et al. 1998, Cat. VIII/65;
2 = Gregory et al. 1996, Cat. VIII/40;
3 = Rengelink et al. 1997, Cat. J/A+AS/124/259;
4 = other (NED).
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [SDSS]
6- 24 A19 --- SDSS SDSS Name, based on J2000.0 position (G1)
26- 30 F5.3 --- z Redshift
32- 36 F5.2 [solLum] logLum Log of [OIII]λ(5007) luminosity in
solar units
38- 40 I3 mJy F60um ? Flux at 60 microns
42- 43 I2 mJy e_F60um ? Nominal error in F60um
45- 48 F4.2 --- c60um ? Confidence level of the 60 micron detection
50- 53 I4 mJy F100um ? Flux at 100 microns
55- 57 I3 mJy e_F100um ? Nominal error in F100um
59- 62 F4.2 --- c100um ? Confidence level of the 100 micron detection
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [SDSS]
6- 24 A19 --- SDSS SDSS Name, based on J2000.0 position (G1)
27- 31 F5.3 --- z Redshift
34- 37 F4.2 [solLum] logLum Log of [OIII]λ(5007) luminosity in
solar units
40- 43 F4.2 arcmin Offset Offset between the SDSS and the RASS positions
46- 50 F5.3 ct/s CR Count rate
53- 55 F3.1 --- HR1 Hardness ratio 1 (1)
58- 60 F3.1 --- HR2 Hardness ratio 2 (1)
63- 67 F5.2 [10-7W] logLX log(LX) in units of erg/s
70- 72 A3 --- Com [yes no] Radio-loud ?
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Note (1): Hardness ratios HR1 and HR2 are defined in Voges et al.
(1999, Cat. IX/10A). From the source counts in the band A and the
band B HR1 is given by: HR1=(B-A)/(B+A). HR2 is determined from the
source counts in the bands C and D by: HR2=(D-C)/(D+C). Since
background subtraction is involved, the source counts in some bands
may be negative. Both values can vary between -1 and 1.
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Global Notes:
Note (G1): J2000.0 coordinates are given as hhmmss.ss+ddmmss.s.
History:
From electronic version of the journal
References:
Zakamska et al., Paper I 2003AJ....126.2125Z 2003AJ....126.2125Z, Cat. J/AJ/126/2125
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 07-Mar-2005