J/ApJ/703/2033 Lyman-break galaxies (LBG) in the HUDF (Rafelski+, 2009)
Deep Keck u-band imaging of the Hubble Ultra Deep Field: a catalog of
z ∼ 3 Lyman break galaxies.
Rafelski M., Wolfe A.M., Cooke J., Chen H.-W., Armandroff T.E., Wirth G.D.
<Astrophys. J., 703, 2033-2050 (2009)>
=2009ApJ...703.2033R 2009ApJ...703.2033R
ADC_Keywords: Galaxy catalogs ; Redshifts ; Photometry, narrow-band ;
Photometry, HST
Keywords: cosmology: observations - galaxies: distances and redshifts -
galaxies: evolution - galaxies: general - galaxies: high-redshift -
galaxies: photometry
Abstract:
We present a sample of 407 z∼3 Lyman break galaxies (LBGs) to a
limiting isophotal u-band magnitude of 27.6mag in the Hubble Ultra
Deep Field. The LBGs are selected using a combination of photometric
redshifts and the u-band drop-out technique enabled by the
introduction of an extremely deep u-band image obtained with the
Keck I telescope and the blue channel of the Low Resolution Imaging
Spectrometer. The Keck u-band image, totaling 9hr of integration time,
has a 1σ depth of 30.7mag/arcsec2, making it one of the most
sensitive u-band images ever obtained. The u-band image also
substantially improves the accuracy of photometric redshift
measurements of ∼50% of the z∼3 LBGs, significantly reducing the
traditional degeneracy of colors between z∼3 and z∼0.2 galaxies.
Description:
The u-band (λ0∼3400Å, FWHM∼690Å) images of the UDF
(J033239-274729) were obtained with the 10m Keck I telescope using the
LRIS. The observations were carried out in dark time over two runs,
2007 October 7-9 (three half nights) and 2007 December 3-4 (two half
nights).
Throughout the paper, we utilize the B, V, i', and z' band (F435W,
F606W, F775W, and F850LP, respectively) observations of the UDF
(Beckwith et al. 2006, Cat. J/AJ/132/1729), obtained with the Wide
Field Camera (WFC) on the HST Advance Camera for Surveys (ACS).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 85 1458 Catalog of u-band objects
table2.dat 119 1458 Catalog of Bayesian photometric redshifts
table3.dat 108 100 Catalog of galaxies with reliable spectroscopic
redshifts in the UDF
table4.dat 96 407 Catalog of z∼3 LBGs in the UDF
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
II/258 : Hubble Ultra Deep Field Catalog (UDF) (STScI, 2004)
J/A+A/478/83 : GOODS-South Field VLT/FORS2 redshifts. III. (Vanzella+, 2008)
J/AJ/134/169 : Redshifts of UDF emission-line objects (Xu+, 2007)
J/AJ/132/1729 : Hubble Ultra Deep Field BVI-dropout sources (Beckwith+, 2006)
J/AJ/132/926 : Galaxies in the Hubble Ultra Deep Field (Coe+, 2006)
J/A+A/454/423 : GOODS-South Field VLT/FORS2 redshifts. II. (Vanzella+, 2006)
J/ApJ/639/724 : Tadpole galaxies in the Hubble UDF (Straughn+, 2006)
J/AJ/130/1 : Catalog of source parameters in NICMOS UDF (Thompson+, 2005)
J/A+A/434/53 : GOODS-South Field redshifts (Vanzella+, 2005)
J/ApJS/150/1 : VV29 and NGC 4676 HST photometry (Benitez+, 2004)
J/A+A/428/1043 : Redshifts from VIMOS VLT Deep Survey (Le Fevre+, 2004)
J/ApJS/155/271 : Chandra Deep Field-South: Optical spectroscopy (Szokoly+,
2004)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- [CBS2006] ID from Coe et al. catalog (G1)
8- 18 F11.8 deg RAdeg Right Ascension in decimal degrees (J2000)
21- 32 F12.8 deg DEdeg Declination in decimal degrees (J2000)
35- 39 F5.2 mag umag KeckI/LRIS u-band (∼3400Å) total magnitude
(1)
42- 45 F4.2 mag e_umag σ of magnitude in u-band
48- 54 F7.2 --- S/N Signal to noise ratio of u-band flux
57- 61 I5 --- CovID ID of most significant neighbor
affecting photometry
64- 68 F5.3 --- CovIdx Absolute value of ratio of Variance
and covariance
71- 77 F7.3 --- FRatio Ratio of V-band fluxes of object and
most significant neighbor
80- 85 F6.3 arcsec Dist Distance to most significant neighbor
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Note (1): Total u-band magnitudes for the same aperture as the V-band
in Coe et al. 2006, Cat. J/AJ/132/926.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- [CBS2006] ID from Coe et al. catalog (G1)
8- 11 F4.2 --- zb Bayesian Photo-Z (BPZ) most likely redshift
14- 17 F4.2 --- b_zb Lower limit (95% confidence) in zb
20- 23 F4.2 --- B_zb Upper limit (95% confidence) in zb
26- 29 F4.2 --- tb BPZ most likely spectral type (1)
32- 36 F5.3 --- odds P(z) contained within 0.1*(1+zb) (2)
39- 44 F6.2 --- chinu Quality of BPZ fit: observed vs. model fluxes
47- 52 F6.2 --- chimod Modified chi2 (includes model uncertainties)
55- 58 F4.2 --- zb1 BPZ most-likely redshift
61- 64 F4.2 --- b_zb1 Lower bound zb1min for highest peak in P(z)
67- 70 F4.2 --- B_zb1 Upper bound zb1max for highest peak in P(z)
73- 76 F4.2 --- tb1 [1/8] BPZ most-likely spectral type (2)
79- 83 F5.3 --- odds1 P(z) between zb1min and zb1max
86- 90 F5.2 --- zb2 ?=-1 BPZ 2nd-most-likely redshift (3)
93- 97 F5.2 --- b_zb2 ?=-1 Lower bound for 2nd-highest peak in P(z)
(3)
100-104 F5.2 --- B_zb2 ?=-1 Upper bound for 2nd-highest peak in P(z)
(3)
107-111 F5.2 --- tb2 ?=-1 BPZ 2nd-most-likely spectral type (2)(3)
114-119 F6.3 --- odds2 ?=-1 P(z) between zb2min and zb2max (3)
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Note (1): SED template type (tb) can be useful when selecting a specific
type of galaxy, where 1=El, 2=Scd, 3=Sbc, 4=Im (cww types from Coleman,
Wu and Weedman 1980ApJS...43..393C 1980ApJS...43..393C) 5=SB3, 6=SB2 (from Kinney et al.
1996ApJ...467...38K 1996ApJ...467...38K), 7=25Myr, and 8=5Myr. For instance, in selecting
LBGs we constrain ourselves to galaxies with tb>3, which only
include star-forming galaxy templates.
A re-calibration of the SED template set improves the performance of
the photometric redshifts, and we use the re-calibrated SED templates
from Benitez et al. (2004, Cat. J/ApJS/150/1) and Coe et al. (2006,
Cat. J/AJ/132/926) that have been extensively tested with BPZ. These
re-calibrated SEDs are based on the star-forming (Im), spiral (Scd,
Sbc), and elliptical (El) galaxy templates from Coleman et al.
(1980ApJS...43..393C 1980ApJS...43..393C), the star bursting galaxy templates with
different reddening (SB2, SB3) from Kinney et al.
(1996ApJ...467...38K 1996ApJ...467...38K), and the faint blue galaxy SEDs with ages of 25
and 5Myr and metallicities of Z=0.08 without dust from Bruzual &
Charlot (2003MNRAS.344.1000B 2003MNRAS.344.1000B), described in section Section 4.1 of Coe
et al. (2006, Cat. J/AJ/132/926).
Note (2): For each galaxy, z-phot codes produce a probability distribution
function, P(z), representing the probability of a galaxy being at any
specific redshift. However, the P(z) can have multiple peaks,
especially at z∼3 where there is a degeneracy with galaxies at z∼0.2,
which then translates into large uncertainties for the z-phot (Benitez
2000ApJ...536..571B 2000ApJ...536..571B).
Note (3): -1.0 denotes an empty field in the table if only 1 peak in P(z).
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- [CBS2006] ID from Coe et al. catalog (G1)
8- 14 A7 --- r_zsp Denotes the survey for zsp (1)
17- 20 F4.2 --- zsp Spectroscopic redshift
23- 26 F4.2 --- zb BPZ most likely redshift
29- 32 F4.2 --- e_zb Lower limit (95% confidence) in zb
35- 38 F4.2 --- E_zb Upper limit (95% confidence) in zb
41- 45 F5.2 --- chimod Modified chi2 (includes model uncertainties)
48- 51 F4.2 --- odds P(z) contained within 0.1*(1+zb)
54- 59 F6.2 mag Vmag Total V band AB magnitude (2)
62- 66 F5.2 mag e_Vmag σ uncertainty in Vmag
69- 73 F5.2 mag u-V (u-V) isophotal color index (2)
76- 80 F5.2 mag e_u-V σ uncertainty in u-V
83- 87 F5.2 mag u-B (u-B) isophotal color index (2)
90- 94 F5.2 mag e_u-B σ uncertainty in u-B
97-101 F5.2 mag V-z' (V-z') isophotal color index (2)
104-108 F5.2 mag e_V-z' σ uncertainty in V-z'
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Note (1): Redshift surveys as follows:
VVDS = Fevre et al. 2004, Cat. J/A+A/428/1043; in Simbad.
VIMOS = Popesso et al. 2009A&A...494..443P 2009A&A...494..443P,
Szokoly = Szokoly et al. 2004, Cat. J/ApJS/155/271
FORS2 = Vanzella et al. 2005, Cat. J/A+A/434/53, 2006, Cat. J/A+A/454/423,
2008, Cat. J/A+A/478/83 and 2009ApJ...695.1163V 2009ApJ...695.1163V.
Note (2): All photometry other than the u-band are from Coe et al. (2006,
Cat. J/AJ/132/926). Nondetections in u-band are given 3σ
limiting magnitudes.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 --- [CBS2006] ID from Coe et al. catalog (G1)
8- 11 F4.2 --- zb BPZ most likely redshift
14- 17 F4.2 --- e_zb Lower limit (95% confidence) in zb
20- 23 F4.2 --- E_zb Upper limit (95% confidence) in zb
26- 30 F5.2 --- chimod Modified chi2: includes model uncertainties
33- 36 F4.2 --- odds P(z) contained within 0.1*(1+zb)
39 I1 --- type [1,3] Type of LBG selection (1)
42- 47 F6.2 mag Vmag Total V band AB magnitude (2)
50- 54 F5.2 mag e_Vmag σ uncertainty in Vmag
57- 61 F5.2 mag u-V (u-V) isophotal color (2)
64- 68 F5.2 mag e_u-V σ uncertainty in u-V
71- 75 F5.2 mag u-B (u-B) isophotal color (2)
78- 82 F5.2 mag e_u-B σ uncertainty in u-B
85- 89 F5.2 mag V-z' (V-z') isophotal color (2)
92- 96 F5.2 mag e_V-z' σ uncertainty in V-z'
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Note (1): LBG selection type as follows:
1 = Both color selection and photometric redshift.
2 = Photometric redshift;
3 = Color selection.
Note (2): All photometry other than the u-band are from Coe et al.
(2006, Cat. J/AJ/132/926). Nondetections in u-band are given 3σ
limiting magnitudes.
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Global notes:
Note (G1): Identifications correspond to:
* 1-40000 correspond to Beckwith et al. ACS catalog
(2006, Cat. J/AJ/132/1729);
* 40001-41000 correspond to Thompson et al. v.1 NIC3 catalog
(2006pces.conf..195T, see also Cat. J/AJ/130/1).
* >50000 correspond to Coe et al, 2006, Cat. J/AJ/132/926;
<[CBS2006] NNNNN> in Simbad.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 03-Nov-2011