J/ApJS/172/383 AGN candidates in the COSMOS field (Trump+, 2007)
Magellan spectroscopy of AGN candidates in the COSMOS field.
Trump J.R., Impey C.D., McCarthy P.J., Elvis M., Huchra J.P., Brusa M.,
Hasinger G., Schinnerer E., Capak P., Lilly S.J., Scoville N.Z.
<Astrophys. J. Suppl. Ser., 172, 383-395 (2007)>
=2007ApJS..172..383T 2007ApJS..172..383T
ADC_Keywords: Surveys ; Active gal. nuclei ; QSOs ; Redshifts
Keywords: galaxies: active - quasars: general - surveys
Abstract:
We present spectroscopic redshifts for the first 466 X-ray and
radio-selected AGN targets in the 2deg2 COSMOS field. Spectra were
obtained with the IMACS instrument on the Magellan (Baade) telescope,
using the nod-and-shuffle technique. We identify a variety of type 1
and type 2 AGNs, as well as red galaxies with no emission lines. Our
redshift yield is 72% down to iAB=24, although the yield is >90% for
iAB<22. We expect the completeness to increase as the survey
continues. When our survey is complete and additional redshifts from
the zCOSMOS project are included, we anticipate ∼1100 AGNs with
redshifts over the entire COSMOS field. Our redshift survey is
consistent with an obscured AGN population that peaks at z∼0.7,
although further work is necessary to disentangle the selection
effects.
Description:
Our observations were taken with IMACS. The field of view of the IMACS
camera is 22'30"x21'10", so that a tiling of 16 IMACS pointings will
cover the entire 2deg2 COSMOS field.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 97 466 COSMOS IMACS AGN catalog
--------------------------------------------------------------------------------
See also:
II/284 : COSMOS Multi-Wavelength Photometry Catalog (Capak+, 2007)
J/ApJS/172/368 : AGN in XMM-Newton survey in COSMOS field (Mainieri+, 2007)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- --- [COSMOS]
8- 26 A19 --- [TIM2007] Object name (JHHMMSS.ss+DDMMSS.s),
[TIM2007] JHHMMSS.ss+DDMMSS.s in Simbad
28- 38 F11.7 deg RAdeg Right Ascension in decimal degrees (J2000)
40- 48 F9.7 deg DEdeg Declination in decimal degrees (J2000)
50- 54 F5.2 --- imag HST/ACS i band AB magnitude
56- 61 F6.2 --- S/N Signal-to-noise
63- 67 I5 --- Texp Exposure time
69- 73 A5 --- Type Source classification (1)
75- 82 F8.5 --- z ?=-1.00000 Redshift
84 A1 --- n_z [c] Manually assigned z (2)
86- 93 F8.5 --- e_z ?=-1.00000 The 1σ error in z
95 A1 --- nez [b] Manually assigned e_z (3)
97 A1 --- zconf Confidence note on z (4)
--------------------------------------------------------------------------------
Note (1): Source type as follows:
q1 = Type 1 AGN
q2 = Type 2 AGN
e = red galaxy
q2e = Type 2 AGN and red galaxy hybrid
mstar = M-type stars
? = questionable classification
q? = blue continua but no obvious emission lines
e? = red continua and no emission or absorption lines
Note (2): 'c' indicates that these zconf=2 Type 1 AGN had their redshifts
manually adjusted to be more consistent with their u*(CFHT)-B(Subaru)
and V(Subaru)-r(Subaru) colors.
Note (3): 'b' indicates objects with a manually assigned redshift error
derived from the 5-pixel spectral resolution.
Note (4): Note on zconf as follows:
1 = redshift is considered unambiguous
2 = only one line fit or the redshift comes strictly from a
well-fit continuum shape over the entire spectral range
? = signal-to-noise of the object spectrum was too low for
a redshift to be determined
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 04-Mar-2008