Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The peculiar motions of early-type galaxies in two distant regions - II.
  The spectroscopic data   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 Mg2 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 zeropoint or scale before being
combined, yielding a total of 706 redshifts, 676 velocity dispersions, 676 Mgb
linestrengths and 582 Mg2 linestrengths. The median estimated errors in the
combined measurements are dcz=20 km/s, dsigma/sigma=9.1%, dMgb/Mgb=7.2% and
dMg2=0.015 mag. Comparison of our measurements with published datasets shows no
systematic errors in the redshifts or velocity dispersions and only small
zeropoint corrections to bring our linestrengths onto 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.

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The categories of this paper are: adap-org
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The categories of this paper are: eess
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The categories of this paper are: dg-ga
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The categories of this paper are: acc-phys
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The categories of this paper are: atom-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: gr-qc
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The categories of this paper are: cs
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The categories of this paper are: mtrl-th
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ex
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The categories of this paper are: plasm-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: supr-con
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-ex