J/ApJ/633/630 Low-mass stars found in CFHTLS (Willott+, 2005)
First results from the Canada-France high-z quasar survey: constraints on the
z=6 quasar luminosity function and the quasar contribution to reionization.
Willott C.J., Delfosse X., Forveille T., Delorme P., Gwyn S.D.J.
<Astrophys. J., 633, 630-637 (2005)>
=2005ApJ...633..630W 2005ApJ...633..630W
ADC_Keywords: Stars, dwarfs ; QSOs ; Photometry, infrared
Keywords: cosmology: observations - galaxies: active - quasars: general
Abstract:
We present preliminary results of a new quasar survey being undertaken
with multicolor optical imaging from the Canada-France-Hawaii
Telescope. The current data consist of 3.83deg2 of imaging in the i'
and z' filters to a 10σ limit of z'<23.35. Near-infrared
photometry of 24 candidate 5.7<z<6.4 quasars confirms them all to be
low-mass stars, including two T dwarfs and four or five L dwarfs.
Photometric estimates of the spectral type of the two T dwarfs are T3
and T6.
Description:
In this paper we use optical imaging from the Canada-France-Hawaii
Telescope Legacy Survey (CFHTLS) to search for high-redshift quasars.
The data used come from the first official release: T0001. This
release includes data in the four Deep Survey fields obtained during
the period 2003 June-2004 July. Observations at J band were performed
using the CFHT-IR camera at the CFHT. CFHT-IR is a HgCdTe 10242
array with pixel size 0.211". Observations were carried out in
photometric conditions on UT 2003 November 9-10, 2004 May 4, and 2004
November 23-24.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 68 24 Table of low-mass stars found in the search for
high-z quasars
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See also:
J/AJ/121/31 : High-redshift quasars in SDSS (Fan+, 2001)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Field Field designation
4- 9 A6 --- --- [CFHTLS]
11- 29 A19 --- CFHTLS Name ([WDF2005] CFHTLS JHHMMSS.ss+DDMMSS.s
in Simbad)
31 A1 --- l_i'mag Upper limit flag on i'mag
32- 36 F5.2 mag i'mag i' magnitude (in the AB system) (1)
38- 41 F4.2 mag e_i'mag ? Error in i'mag
43- 47 F5.2 mag z'mag z' magnitude (in the AB system) (1)
49- 52 F4.2 mag e_z'mag Error in z'mag
54 A1 --- l_Jmag Upper limit flag on Jmag
55- 59 F5.2 mag Jmag J magnitude (in the AB system) (1)
61- 64 F4.2 mag e_Jmag ? Error in Jmag
66- 68 A3 --- Note [Yes/No] Included in complete sample? (2)
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Note (1): The magnitudes listed are total magnitudes derived from aperture
magnitudes.
Note (2): Indicates whether the object satisfies the i' and z' selection
criteria that form the basis for our complete sample of quasar
candidates for J-band imaging. These criteria are i'-z'≥1.5,
σ(z')≤0.10, and z'<23.35. The three-color photometry indicates
that all these objects are ultracool dwarfs.
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History:
From electronic version of the journal
(End) Marianne Brouty [CDS] 26-Jul-2006