J/MNRAS/387/1323 SDSS photometry of luminous red galaxies (Ross+, 2008)
Luminous red galaxy clustering at z ≃ 0.7 - First results using AAOmega.
Ross N.P., Shanks T., Cannon R.D., Wake D.A., Sharp R.G., Croom S.M.,
Peacock J.A.
<Mon. Not. R. Astron. Soc., 387, 1323-1334 (2008)>
=2008MNRAS.387.1323R 2008MNRAS.387.1323R
ADC_Keywords: Surveys ; Galaxies, photometry ; Photometry, SDSS
Keywords: surveys - galaxies: statistics - cosmology: observations -
large-scale structure of Universe
Abstract:
We report on the AAT-AAOmega LRG Pilot observing run to establish the
feasibility of a large spectroscopic survey using the new AAOmega
instrument. We have selected luminous red galaxies (LRGs) using single
epoch SDSS riz-photometry to i<20.5 and z<20.2. We have observed in
three fields including the COSMOS field and the COMBO-17 S11 field,
obtaining a sample of ∼600 redshift z≳0.5 LRGs. Exposure times varied
from 14h to determine the minimum exposure for AAOmega to make an
essentially complete LRG redshift survey in average conditions. We
show that LRG redshifts to i<20.5 can be measured in ≫1.5h exposures
and present comparisons with 2SLAQ and COMBO-17 (photo)redshifts.
Crucially, the riz selection coupled with the three to four times
improved AAOmega throughput is shown to extend the LRG mean redshift
from z=0.55 for 2SLAQ to z=0.681±0.005 for riz-selected LRGs. This
extended range is vital for maximizing the signal-to-noise ratio for
the detection of the baryon acoustic oscillations (BAOs). Furthermore,
we show that the amplitude of LRG clustering is
s0=9.9±0.7h-1Mpc, as high as that seen in the 2SLAQ LRG Survey.
Consistent results for this clustering amplitude are found from the
projected and semi-projected correlation functions. This high
amplitude is consistent with a long-lived population whose bias
evolves as predicted by a simple 'high-peak' model. We conclude that
a redshift survey of 360000 LRGs over 3000deg2, with an effective
volume some four times bigger than previously used to detect BAO with
LRGs, is possible with AAOmega in 170 nights.
Description:
Observations were made on the nights of 2006 March 3 to March 7
inclusive; the first three nights were Dark nights, the last two were
Grey nights.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 182 1270 The AAOmega LRG Pilot Catalogue
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See also:
J/MNRAS/354/L25 : MgII absorbers in SDSS QSOs (Bouche+, 2004)
J/MNRAS/372/425 : 2dF-SDSS Luminous Red Galaxy Survey, 2SLAQ (Cannon+, 2006)
J/MNRAS/375/68 : MegaZ-LRG catalogue (Collister+, 2007)
J/MNRAS/377/787 : SDSS Luminous Red Galaxies (Barber+, 2007)
J/MNRAS/381/211 : Radio galaxies in the 2SLAQ LRG Survey (Sadler+, 2007)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- SDSS SDSS Object Designation (JHHMMSS.ss+DDMMSS.s)
20 A1 --- n_SDSS [*] CAUTION! position differs from name !!!
23- 31 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000)
35- 42 F8.5 deg DEdeg Declination in decimal degrees (J2000)
46- 50 F5.2 mag rmagf r-band SDSS Fibre magnitude
54 I1 --- T [1/4] Model galaxy template to fit
observed spectra (1)
58- 62 F5.2 --- Xcor Cross-correlation coefficient between the
model and observed galaxy spectra
66- 72 F7.4 --- z Measured redshift
76 I1 --- q_z [0/5] Redshift quality flag (2)
80- 82 A3 --- Field Field Name (cos, d05 or s11) (3)
86- 92 F7.4 mag umag SDSS u-band Model magnitude
96-102 F7.4 mag gmag SDSS g-band Model magnitude
106-112 F7.4 mag rmag SDSS r-band Model magnitude
116-122 F7.4 mag imag SDSS i-band Model magnitude
126-132 F7.4 mag zmag SDSS z-band Model magnitude
136-142 F7.4 mag e_umag Error in u-band Model magnitude
146-152 F7.4 mag e_gmag Error in g-band Model magnitude
156-162 F7.4 mag e_rmag Error in r-band Model magnitude
166-172 F7.4 mag e_imag Error in i-band Model magnitude
176-182 F7.4 mag e_zmag Error in z-band Model magnitude
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Note (1): Model galaxy template as follows:
1 = early-type template provided the best fit
2 = k+a Balmer absorption spectrum template provided the best fit
3 = M-star template provided the best fit
4 = not explained in the paper
Note (2): A value of 3 or greater represents a >95% confidence that
the redshift obtained from the spectrum is valid.
Note (3): We have observed in three fields defined as follows:
cos = COSMOS field (Scoville et al., 2007ApJS..172....1S 2007ApJS..172....1S)
s11 = COMBO-17 S11 field (Wolf et al., 2003A&A...401...73W 2003A&A...401...73W)
d05 = 2SLAQ Survey field, d05 (Cannon et al., 2006, Cat. J/MNRAS/372/425)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 28-Nov-2008