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J/MNRAS/305/259 EFAR galaxies redshifts & velocity dispersions (Wegner+, 1999)
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The peculiar motions of early-type galaxies in two distant regions - II. The
spectroscopic data.
Wegner G., Colless M., Saglia R.P., McMahan R.K.Jr, Davies R.L.,
Burstein D., Baggley G.
<Mon. Not. R. Astron. Soc. 305, 259 (1999)>
=1999MNRAS.305..259W (SIMBAD/NED BibCode)
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ADC_Keywords: Galaxies, spectra ; Redshifts ; Velocity dispersion
Keywords: surveys - galaxies: clusters: general -
galaxies: distances and redshifts -
galaxies: elliptical and lenticular, cD -
large-scale structure of Universe
Abstract:
We present the spectroscopic data for the galaxies studied in the EFAR
project, which is designed to measure the properties and peculiar
motions of early-type galaxies in two distant regions. We have
obtained 1319 spectra of 714 early-type galaxies over 33 observing
runs on 10 different telescopes. We describe the observations and data
reductions used to measure redshifts, velocity dispersions and the Mgb
and Mg_2_ Lick linestrength indices. Detailed simulations and
intercomparison of the large number of repeat observations lead to
reliable error estimates for all quantities. The measurements from
different observing runs are calibrated to a common zero-point or
scale before being combined, yielding a total of 706 redshifts, 676
velocity dispersions, 676 Mgb linestrengths and 582 Mg_2_
linestrengths. The median estimated errors in the combined
measurements are {Delta}cz=20km/s, {Delta}sigma/sigma=9.1%,
{Delta}Mgb/Mgb=7.2% and {Delta}Mg_2_=0.015mag. Comparison of
our measurements with published data sets shows no systematic errors
in the redshifts or velocity dispersions, and only small zero-point
corrections to bring our linestrengths on to the standard Lick system.
We have assigned galaxies to physical clusters by examining the
line-of-sight velocity distributions based on EFAR and ZCAT redshifts,
together with the projected distributions on the sky. We derive mean
redshifts and velocity dispersions for these clusters, which will be
used in estimating distances and peculiar velocities and to test for
trends in the galaxy population with cluster mass. The spectroscopic
parameters presented here for 706 galaxies combine high-quality data,
uniform reduction and measurement procedures, and detailed error
analysis. They form the largest single set of velocity dispersions and
linestrengths for early-type galaxies published to date.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 108 1318 Individual Spectroscopic Measurements
table5.dat 95 706 Spectroscopic parameters for the EFAR galaxies
table7.dat 41 141 Cluster mean redshifts and velocity dispersions
tables.tex 149 2117 LaTeX version of tables 3 & 5
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See also:
VII/193 : The CfA Redshift Catalogue (ZCAT) (Huchra+ 1995)
J/ApJS/106/1 : EFAR cluster and galaxy selection (Wegner+, 1996)
J/MNRAS/292/499 : EFAR photometric data (Saglia+, 1997)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- GINRUNSEQ Observation identifier
11- 19 A9 --- Name Galaxy name
21- 24 A4 --- Tel Telescope used
26- 33 A8 "DD/MM/YY" ObsDate Observation date
35 A1 --- Qual Quality parameter
36 A1 --- n_Qual [*] *: emission-line object with emission
features listed in Notes column
38- 41 F4.1 --- S/N Signal-to-noise ratio
43- 47 I5 km/s cz ? Redshift
49- 51 I3 km/s e_cz ? rms uncertainty on cz
53- 55 I3 km/s sigma ? Velocity dispersion
57- 59 I3 km/s e_sigma ? rms uncertainty on sigma
61- 64 F4.2 0.1nm Mgb ? Mgb linestrength
66- 69 F4.2 0.1nm e_Mgb ? rms uncertainty on Mgb
71- 75 F5.3 mag Mg2 ? Mg_2_ linestrength
77- 81 F5.3 mag e_Mg2 ? rms uncertainty on Mg2
83-112 A30 --- Notes Notes (1)
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Note (1): double: EFAR galaxy is double
star: EFAR object is a star not a galaxy
mis-ID: spectrum is for some galaxy other than the nominated EFAR
object
mis-ID*: spectrum is for a nearby star rather than the EFAR object
Mgb at sky: object is at a redshift which puts Mgb on the 5577{AA}
sky line
number=number: notes the duplicated pairs in the EFAR sample (see Paper I
(Wegner et al., 1996ApJS..106....1W); only the first of
the two GINs is used)
'H{beta} abs' or `H{beta} abs, [OIII]' means the redshift is based on
the H{beta} absorption feature (and [OIII] if present), as the
spectrum stops short of Mgb no dispersion or Mgb index is given for
these objects).
The objects for which we have no spectrum have GINs:
7, 20, 29, 30, 34, 35, 55, 62, 64, 67, 82, 83, 91, 104,
121, 131, 133, 134, 161, 181, 191, 214, 225, 228, 231, 234, 256, 265,
309, 327, 391, 405, 407, 417, 434, 435, 442, 450, 451, 452, 458, 463,
464, 465, 470, 475, 477, 483, 484, 486, 494, 516, 520, 521, 522, 523,
526, 544, 551, 553, 567, 569, 570, 575, 576, 577, 587, 594, 597, 603,
605, 624, 625, 644, 671, 727, 760, 793, 798, 801, 901.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- GIN Galaxy identification number
5- 13 A9 --- Name Galaxy name
15- 17 I3 --- CAN Cluster assignment number
20 I1 --- Nsp Number of spectra
22 I1 --- Ncz Number of redshifts (1)
24 I1 --- Nsigma Number of dispersions (1)
26 I1 --- NMgb Number of Mgb linestrength (1)
28 I1 --- NMg2 Number of Mg2 linestrength (1)
30- 34 I5 km/s cz Redshift (combined estimate)
36- 37 I2 km/s e_cz Redshift (total error)
39- 41 I3 km/s dcz ? Redshift (weighted rms error)
43- 45 I3 km/s sigma ? Velocity dispersion (combined estimate)
47- 49 I3 km/s e_sigma ? Velocity dispersion (total error)
51- 52 I2 km/s dsigma ? Velocity dispersion (weighted rms error)
54- 57 F4.2 0.1nm Mgb ? Mgb linestrength (combined estimate)
59- 62 F4.2 0.1nm e_Mgb ? Mgb linestrength (total error)
64- 67 F4.2 0.1nm dMgb ? Mgb linestrength (weighted rms error)
69- 73 F5.3 mag Mg2 ? Mg_2_ linestrength (combined estimate)
75- 79 F5.3 mag e_Mg2 ? Mg_2_ linestrength (total error)
81- 85 F5.3 mag dMg2 ? Mg_2_ linestrength (weighted rms error)
87- 91 F5.1 --- S/N Combined signal-to-noise ratio
93 A1 --- Qual Overall quality parameter (1)
94 A1 --- n_Qual [*] *: when galaxies possess emission lines
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Note (1): Only objects with useful measurements are included; hence the lowest
quality class present in this table is Qual = D, and the seven
galaxies with only Qual = E spectra (GINs 123, 284, 389, 448, 599,
637 and 679) are omitted.
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- CAN Cluster assignment number
5- 6 I2 --- N1 Number of EFAR galaxies
9- 13 I5 km/s <cz>1 EFAR average redshift
15- 17 I3 km/s e_<cz>1 rms uncertainty on <cz>1
19- 22 I4 km/s sigma1 ? EFAR velocity dispersion
24- 26 I3 --- N2 Number of EFAR+ZCAT galaxies
28- 32 I5 km/s <cz>2 EFAR+ZCAT average redshift
34- 36 I3 km/s e_<cz>2 rms uncertainty on <cz>2
38- 41 I4 km/s sigma2 ? EFAR+ZCAT velocity dispersion
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Acknowledgements: Matthew Colless <colless@mso.anu.edu.au>
References:
Wegner et al., Paper I 1996ApJS..106....1W
Saglia et al., Paper III 1997MNRAS.292..499S
Saglia et al., Paper IV 1997ApJS..109...79S
Coless et al., Paper V 1999MNRAS.303..813C
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(End) James Marcout, Patricia Bauer [CDS] 02-Aug-1999