J/AJ/154/113 Magellan/M2FS spectroscopy of Abell 267 (Tucker+, 2017)
Magellan/M2FS spectroscopy of galaxy clusters: stellar population model and
application to Abell 267.
Tucker E., Walker M.G., Mateo M., Olszewski E.W., Bailey J.I., Crane J.D.,
Shectman S.A.
<Astron. J., 154, 113-113 (2017)>
=2017AJ....154..113T 2017AJ....154..113T (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Galaxies, spectra ; Abundances, [Fe/H] ;
Abundances ; Velocity dispersion
Keywords: galaxies: clusters: individual: Abell 267 - galaxies: general -
techniques: imaging spectroscopy
Abstract:
We report the results of a pilot program to use the Magellan/M2FS
spectrograph to survey the galactic populations and internal
kinematics of galaxy clusters. For this initial study, we present
spectroscopic measurements for 223 quiescent galaxies observed along
the line of sight of the galaxy cluster Abell 267 (z∼0.23). We develop
a Bayesian method for modeling the integrated light from each galaxy
as a simple stellar population, with free parameters that specify the
redshift (vlos/c) and characteristic age, metallicity ([Fe/H]),
alpha-abundance ([α/Fe]), and internal velocity dispersion
(σint) for individual galaxies. Parameter estimates derived
from our 1.5hr observation of A267 have median random errors of
σVlos=20km/s, σAge=1.2Gyr, σ[Fe/H]=0.11dex,
σ[α/Fe]=0.07dex, and σσint=20km/s. In a
companion paper, we use these results to model the structure and
internal kinematics of A267.
Description:
We select targets for Michigan/Magellan Fiber System (M2FS)
observations by identifying galaxies detected in SDSS images (Data
Release 12; Alam et al.2015, Cat. V/147) that are projected along the
line of sight to Abell 267 and are likely to be quiescent cluster
members.
We observed 223 individual galaxy spectra on 2013 November 30 on the
Clay Magellan Telescope using M2FS. We used the low-resolution grating
on M2FS and chose a coverage range of 4600-6400Å with a resolution
of R∼2000. The detector used with M2FS consists of two 4096*4112 pixel
CCDs.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 100 223 Results for fitting of A267 spectra
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See also:
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
J/ApJ/819/53 : Magellan/M2FS spectroscopy of Tucana 2 & Grus 1 (Walker+, 2016)
J/ApJ/797/106 : Redshifts in nine galaxy cluster fields (Hwang+, 2014)
J/ApJ/767/15 : Hectospec Cluster Survey (HeCS) (Rines+, 2013)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/223] Michigan/Magellan Fiber System (M2FS)
target, sequential identifier
5- 6 I2 h RAh Hour of Right Ascension (J2000)
8- 9 I2 min RAm Minute of Right Ascension (J2000)
11- 15 F5.2 s RAs Second of Right Ascension (J2000)
17 A1 --- DE- Sign of the Declination (J2000)
18- 19 I2 deg DEd Degree of Declination (J2000)
21- 22 I2 arcmin DEm Arcminute of Declination (J2000)
24- 27 F4.1 arcsec DEs Arcsecond of Declination (J2000)
29- 33 F5.2 mag rmag [18.8/21.1] SDSS r band magnitude
35- 39 F5.2 mag imag [18.4/20.7] SDSS i band magnitude
41- 44 F4.1 --- S/N [0.6/32.2] Median spectral Signal-to-Noise per
pixel
46- 51 I6 km/s <Vlos> [11012/133103] Mean Line-of-Sight velocity,
solar rest frame (Vlos)
53- 57 I5 km/s e_<Vlos> [7/45300] Uncertainty in <Vlos>
59- 62 F4.1 Gyr <Age> [0.4/14.8] Mean inferred age
64- 66 F3.1 Gyr e_<Age> [0.2/5.2] Uncertainty in <Age>
68- 72 F5.2 [Sun] <Fe/H> [-3.4/0.5] Mean metallicity relative to Sun
74- 77 F4.2 [Sun] e_<Fe/H> [0.03/0.8] Uncertainty in <Fe/H>
79- 83 F5.2 --- <a/Fe> [-0.1/0.8] Mean chemical abundance [α/Fe]
85- 88 F4.2 --- e_<a/Fe> [0.01/0.4] Uncertainty in <a/Fe>
90- 94 F5.1 km/s [28/437.6] Mean internal velocity dispersion
σint
96-100 F5.1 km/s e_ [3.1/121.2] Uncertainty in
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 07-Feb-2018