J/ApJ/462/614 A deep multicolor survey. II. (Hall+ 1996)
A deep multicolor survey. II. Initial spectroscopy and comparison
with expected quasar number counts.
Hall P.B., Osmer P.S., Green R.F., Porter A.C., Warren S.J.
<Astrophys. J. 462, 614 (1996)>
=1996ApJ...462..614H 1996ApJ...462..614H (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Galaxies, photometry ; Surveys
Keywords: catalogs - galaxies: photometry - quasars: general - surveys
Description:
We have used the Kitt Peak National Observatory 4m Mayall telescope to
image 0.83 square degrees of sky in six fields at high galactic
latitude in six filters spanning 3000-10000A to magnitude limits
ranging from 22.1 to 23.8. As a first use of this database, we have
conducted a multicolor survey for quasars. We discuss various methods
of selecting outliers in different color-color diagrams and multicolor
space that have been used to identify quasars at all redshifts from
their colors alone. We discuss the initial results of our program of
spectroscopic identification which has so far resulted in the
identification of over 40 faint quasars, including one a z>4, a
similar number of compact narrow emission-line galaxies, and a number
of unusual and potentially interesting stars. We use these
spectroscopic results, along with extensive simulations of quasar
spectra, to study the efficiency of our candidate selection
procedures. Finally, we compare the number counts of our quasars
and quasar candidates to the expected numbers based on previous
studies of the quasar luminosity function. The agreement of our
observations with these expectations is good in most cases. However,
we do estimate that our survey contains more quasars with B<21 and
z<2.3 than expected from the results published by Koo & Kron in
(1988ApJ...325...92K 1988ApJ...325...92K) and more z>3 quasars than expected from the
results published by Warren, Hewett & Osmer in (1994ApJ...421..412W 1994ApJ...421..412W),
both at the 3 σ level. Additional spectroscopic observations
will be required to confirm or refute these excesses.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1 71 46 Quasars: identification
table1.tex 86 64 LaTeX version of table1
table2 72 39 Compact narrow emission-line galaxies: identifications
table2.tex 87 58 LaTex Version of table2
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See also:
J/ApJS/104/185 : A deep multicolor survey. I. (Hall+ 1996)
J/AJ/114/2269 : A deep multicolor survey. III (Kennefick+ 1997)
J/ApJS/119/189 : A deep multicolor Survey. IV. (Osmer+ 1998)
Byte-by-byte Description of file: table1 table2
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Bytes Format Units Label Explanations
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1- 2 I2 --- No Sequential number
4- 17 A14 --- Name DMS or N designation (1)
19- 20 I2 h RAh Right ascension (1950.0)
22- 23 I2 min RAm Right ascension (1950.0)
25- 29 F5.2 s RAs Right ascension (1950.0)
31 A1 --- DE- Declination sign
32- 33 I2 deg DEd Declination (1950.0)
35- 36 I2 arcmin DEm Declination (1950.0)
38- 42 F5.2 arcsec DEs Declination (1950.0)
44- 47 F4.1 mag Bmag B magnitude
49- 53 F5.3 --- z ? Redshift
54 A1 --- u_z [?] Uncertainty flag on z
56- 72 A17 --- Notes Notes
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Note (1): DMS followed by the epoch 1950.0 position in table1,
N followed by the epoch 1950.0 position in table2.
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Acknowledgements: Pat Hall
(End) Patricia Bauer [CDS] 03-Oct-1996