J/MNRAS/381/1035 Spectroscopy in Shapley supercluster (Smith+, 2007)
A deep AAOmega survey of low-luminosity galaxies in the Shapley supercluster:
stellar population trends.
Smith R.J., Lucey J.R., Hudson M.J.
<Mon. Not. R. Astron. Soc., 381, 1035-1052 (2007)>
=2007MNRAS.381.1035S 2007MNRAS.381.1035S
ADC_Keywords: Clusters, galaxy ; Galaxies, spectra ; Spectroscopy
Keywords: galaxies: clusters: general -
galaxies: elliptical and lenticular, cD - galaxies: evolution
Abstract:
We present new optical spectroscopy for 342 R<18 galaxies in the
Shapley supercluster (and 198 supplementary galaxies), obtained from
8-h integrations with the AAOmega facility at the Anglo-Australian
Telescope. We describe the observations and measurements of central
velocity dispersion σ, emission-line equivalent widths and
absorption-line indices. The distinguishing characteristic of the
survey is its coverage of a very wide baseline in velocity dispersion
(90 per cent range σ=40-230km/s), while achieving high
signal-to-noise ratio throughout (median 60Å-1 at 5000Å). The
data quality will enable estimates of Balmer-line ages to better than
20 per cent precision even for the faintest galaxies in the sample.
Significant emission at Hα was detected in ∼30 per cent of the
supercluster galaxies, including ∼20 per cent of red-sequence members.
Using line-ratio diagnostics, we find that the emission is LINER (low
ionization nuclear emission region) like at high luminosity, but
driven by star formation in low-luminosity galaxies. To characterize
the absorption lines, we use the classical Lick indices in the
spectral range 4000-5200Å. We introduce a new method for applying
resolution corrections to the line-strength indices. We define a
subset of galaxies with very low emission contamination, based on the
Hα line, and fit the index relations for this subset.
The final sample analysed in this paper comprises 232 NFPS-selected
galaxies meeting both the emission and the redshift criteria, of which
198 have measured velocity dispersions (i.e. are not unresolved).
Description:
Spectroscopic observations were made with the AAOmega system on the
3.9-m AAT, on the nights of 2006 April 26 and 29. AAOmega consists of
the 2dF fibre positioner, linked to an efficient and stable
bench-mounted dual-beam spectrograph.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tables.dat 232 232 Basic data, principal and supplementary
line-strength indices for the sample galaxies
(tables 2, 3 and 4 of the paper)
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See also:
J/AJ/110/463 : Kinematics of the Shapley supercluster (Quintana+ 1995)
J/A+AS/119/329 : VR photometry in the Shapley Supercluster (Slezak+, 1996)
J/A+AS/120/357 : R magnitudes in four ESO fields (Infante+, 1996)
J/other/PASA/16.113 : New structure in Shapley supercluster (Drinkwater+, 1999)
J/MNRAS/312/540 : Redshift survey of intercluster galaxies (Bardelli+, 2000)
J/AJ/130/2541 : Core of the Shapley supercluster at 1.4GHz (Miller+, 2005)
J/A+A/445/819 : Systems of galaxies in Shapley supercluster (Ragone+, 2006)
J/AJ/128/1558 : NOAO Fundamental Plane Survey (Smith+, 2004)
Byte-by-byte Description of file: tables.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [NFP]
4- 19 A16 --- NFP NFP galaxy designation (JHHMMSS.s+DDMMSS)
21- 23 I3 --- S/N Signal-to-noise ratio measured over a
rest-frame interval of 4500-5500Å
25- 29 I5 km/s cz Heliocentric radial velocity
31- 35 F5.2 mag Rmag Total (Harris) R magnitude from NFPS photometry
37- 41 F5.2 mag Bmag Total (Harris) B magnitude from NFPS photometry
43- 47 F5.3 [km/s] logSv ? Velocity dispersion (2) (1)
49- 53 F5.3 [km/s] e_logSv ? rms uncertainty on logsigma
55- 59 F5.3 --- Mgb5177 Non-degenerate absorption-line index
Mgb5177 (3) (2)
61- 65 F5.3 --- e_Mgb5177 rms uncertainty on Mgb5177
67- 71 F5.3 --- Fe5015 ?=- Non-degenerate absorption-line index
Fe5015 (2) (3)
73- 77 F5.3 --- e_Fe5015 ?=- rms uncertainty on Fe5015
79- 84 F6.3 --- HgF ?=- Non-degenerate absorption-line index
HgF (2) (3)
86- 90 F5.3 --- e_HgF ?=- rms uncertainty on HgF
92- 96 F5.2 --- HdA HdA line-strength index
98-101 F4.2 --- e_HdA rms uncertainty on HdA
103-107 F5.2 --- HdF HdF line-strength index
109-112 F4.2 --- e_HdF rms uncertainty on HdF
114-119 F6.3 --- CN1 CN1 line-strength index
121-125 F5.3 --- e_CN1 rms uncertainty on CN1
127-132 F6.3 --- CN2 CN2 line-strength index
134-138 F5.3 --- e_CN2 rms uncertainty on CN2
140-144 F5.2 --- Ca4227 Ca4227 line-strength index
146-149 F4.2 --- e_Ca4227 rms uncertainty on Ca4227
151-154 F4.2 --- G4300 G4300 line-strength index
156-159 F4.2 --- e_G4300 rms uncertainty on G4300
161-165 F5.2 --- HgA ?=- HgA line-strength index
167-170 F4.2 --- e_HgA ?=- rms uncertainty on HgA
172-175 F4.2 --- Fe4383 ?=- Fe4383 line-strength index
177-180 F4.2 --- e_Fe4383 ?=- rms uncertainty on Fe4383
182-185 F4.2 --- Ca4455 ?=- Ca4455 line-strength index
187-190 F4.2 --- e_Ca4455 ?=- rms uncertainty on Ca4455
192-196 F5.2 --- Fe4531 ?=- Fe4531 line-strength index
198-201 F4.2 --- e_Fe4531 ?=- rms uncertainty on Fe4531
203-206 F4.2 --- Fe4668 ?=- Fe4668 line-strength index
208-211 F4.2 --- e_Fe4668 ?=- rms uncertainty on Fe4668
213-216 F4.2 --- Hbeta Hβ line-strength index
218-221 F4.2 --- e_Hbeta rms uncertainty on Hbeta
223-227 F5.2 --- Fe5406 Fe5406 line-strength index
229-232 F4.2 --- e_Fe5406 rms uncertainty on Fe5406
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Note (1): Galaxies with missing data in this column are those for which
the dispersion was unresolved.
Note (2): Velocity dispersions and line indices are as observed through
a 142-140 aperture, corresponding to 1.9kpc in our adopted cosmology
Note (3): Indices have been corrected to the Lick resolution and to zero
intrinsic velocity broadening.
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History:
20-Mar-2008: From electronic version of the journal
04-Mar-2009: magnitudes B and R were inverted, now corrected
(End) Patricia Vannier [CDS] 07-Feb-2008