J/ApJ/850/181 Spectroscopic analysis of EDisCS clusters (Rudnick+, 2017)
Determining the halo mass scale where galaxies lose their gas.
Rudnick G., Jablonka P., Moustakas J., Aragon-Salamanca A., Zaritsky D.,
Jaffe Y.L., De Lucia G., Desai V., Halliday C., Just D., Milvang-Jensen B.,
Poggianti B.
<Astrophys. J., 850, 181 (2017)>
=2017ApJ...850..181R 2017ApJ...850..181R
ADC_Keywords: Clusters, galaxy; Galaxies, spectra; Redshifts; Equivalent widths;
Optical
Keywords: galaxies: evolution ; galaxies: groups: general ; galaxies: ISM
Abstract:
A major question in galaxy formation is how the gas supply that fuels
activity in galaxies is modulated by their environment. We use
spectroscopy of a set of well-characterized clusters and groups at
0.4<z<0.8 from the ESO Distant Cluster Survey and compare it to
identically selected field galaxies. Our spectroscopy allows us to
isolate galaxies that are dominated by old stellar populations. Here
we study a stellar-mass-limited sample (log(M*/M☉)>10.4) of
these old galaxies with weak [OII] emission. We use line ratios and
compare to studies of local early-type galaxies to conclude that this
gas is likely excited by post-AGB stars and hence represents a diffuse
gas component in the galaxies. For cluster and group galaxies the
fraction with EW([OII])>5Å is f[OII]=0.08-0.02+0.03 and
f[OII]=0.06-0.04+0.07, respectively. For field galaxies we find
f[OII]=0.27-0.06+0.07, representing a 2.8σ difference
between the [OII] fractions for old galaxies between the different
environments. We conclude that a population of old galaxies in all
environments has ionized gas that likely stems from stellar mass loss.
In the field galaxies also experience gas accretion from the cosmic
web, and in groups and clusters these galaxies have had their gas
accretion shut off by their environment. Additionally, galaxies with
emission preferentially avoid the virialized region of the cluster in
position-velocity space. We discuss the implications of our results,
among which is that gas accretion shutoff is likely effective at group
halo masses (logM/M☉>12.8) and that there are likely multiple
gas removal processes happening in dense environments.
Description:
Our data are in fields observed by the ESO Distant Cluster Survey
(EDisCS). The exact selection of the parent EDisCS fields and the main
clusters is described in detail in White+ (2005, J/A+A/444/365). In
some fields there are additional clusters and groups serendipitously
discovered along the line of sight.
Each field was observed with BVIKs, BVIJKs, or VRIJKs photometry
depending on the initial redshift estimate. The optical data were
obtained with VLT/FORS2 and the near-IR data with NTT/SOFI.
Vega-to-AB magnitude conversions were computed by integrating the
spectrum of Vega over our filter curves.
We use visual morphologies derived from Hubble Space Telescope (HST)
F814W imaging of 10 of the EDisCS fields (Desai+ 2007, J/ApJ/660/1151).
This observed filter corresponds to rest-frame B- or V-band imaging of
our systems depending on the redshift of the sample.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 41 24 Cluster and group data
table2.dat 119 469 Galaxy data
--------------------------------------------------------------------------------
See also:
J/ApJS/98/477 : Optical spectral atlas of Seyfert nuclei (Ho+ 1995)
J/ApJS/111/377 : Hγ & Hδ absorption features (Worthey+ 1997)
J/ApJS/116/1 : Old Stellar Populations. VI. Absorption-Line (Trager+ 1998)
J/A+A/427/397 : Redshifts of 5 EDisCS galaxy clusters (Halliday+, 2004)
J/A+A/444/365 : ESO Distant Cluster Survey, EDisCS (White+, 2005)
J/MNRAS/371/1777 : X-ray properties of 3 EDisCS gal. clusters (Johnson+, 2006)
J/ApJ/630/206 : Hα data for 3 EDisCS galaxy clusters (Finn+, 2005)
J/ApJ/660/1151 : Morphology of galaxies in 10 EDisCS clusters (Desai+, 2007)
J/A+A/482/419 : EDisCS. II (Milvang-Jensen+, 2008)
J/A+A/499/47 : Lick indices of EDCSN galaxies (Sanchez-Blazquez+, 2009)
J/A+A/519/A40 : Spectroscopic study of 65 nearby galaxies (Annibali+, 2010)
J/ApJS/190/233 : Spectroscopy & abundances of SINGS gal. (Moustakas+, 2010)
J/A+A/524/A6 : Evolution of spectral early-type galaxies (Saglia+, 2010)
J/MNRAS/413/813 : ATLAS3D project. I. (Cappellari+, 2011)
J/MNRAS/414/940 : ATLAS3D project. IV. (Young+, 2011)
J/ApJ/750/93 : NIR observations of XMM-LSS J02182-05102 (Papovich+, 2012)
J/MNRAS/436/34 : GALEX Arecibo SDSS survey. Final DR (Catinella+, 2013)
J/ApJ/794/156 : 0.3<z<1.4 gal. MgII/FeII absorption profiles (Rubin+, 2014)
J/MNRAS/446/2030 : FUV and NUV magnitudes of ETG (Zaritsky+, 2015)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- OType Cl=Cluster or Gr=Group
4- 5 A2 --- --- [CL]
7- 18 A12 --- Syst System name (CL HHMM.m+DDMMa; J2000) (1)
20- 25 F6.4 --- z [0.3/0.8] Redshift
27- 30 I4 km/s sigma [179/1080] Velocity dispersion (2)
32- 34 I3 km/s e_sigma [26/139] Negative uncertainty on sigma
36- 38 I3 km/s E_sigma [40/136] Positive uncertainty on sigma
40- 41 I2 --- Ng [1/42] Number of galaxies meeting our stellar
mass and quality cuts
--------------------------------------------------------------------------------
Note (1): Clusters from EDisCS II (Milvang-Jensen+, 2008, J/A+A/482/419) are
<[MNH2008] cl JHHMM.m+DDMMa> in Simbad;
Note (2): This was computed using the full EDisCS member sample, which is
larger than the sample used for the analysis in this paper.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- --- [EDCSN]
6- 21 A16 --- EDCS Source identifier (JHHMMSSs+DDMMSSs)
23- 28 F6.4 --- zspec [0.2/1] Spectroscopic redshift
30 A1 --- l_EW-O2 The 1σ upper limit flag on EW-O2 (1)
32- 37 F6.2 0.1nm EW-O2 [0.08/60.4] [OII]3727Å equivalent width
39- 42 F4.2 0.1nm e_EW-O2 [0.3/4.7]? Uncertainty in EW-O2
44 A1 --- l_EW-O3 The 1σ upper limit flag on EW-O3
46- 51 F6.2 0.1nm EW-O3 [0.2/107]? [OIII]4959,5007Å equivalent
width (2)
53- 56 F4.2 0.1nm e_EW-O3 [0.1/3]? Uncertainty in EW-O3
58 A1 --- l_EW-Hb/e The 1σ upper limit flag on EW-Hb,e (3)
60- 65 F6.2 0.1nm EW-Hb/e [0.4/21.4]? Hβ emission equivalent
width (2)
67- 70 F4.2 0.1nm e_EW-Hb/e [0.1/2]? Uncertainty in EW-Hb,e
72- 77 F6.2 0.1nm EW-Hd/a [-10.7,10] Hδ absorption equivalent
width
79- 82 F4.2 0.1nm e_EW-Hd/a [0.2/4.4] Uncertainty in EW-Hd,a
84- 89 F6.2 0.1nm EW-Hg/a [-34/10.6] Hγ absorption equivalent
width
91- 95 F5.2 0.1nm e_EW-Hg/a [0.2/3.2]? Uncertainty in EW-Hg,a
97-100 F4.2 --- Dn4000 [1.1/3.9] The 4000Å break index
102-105 F4.2 --- e_Dn4000 [0.01/1.3] Uncertainty in Dn4000
107-111 F5.2 [Msun] logM* [10.4/11.8] Log stellar mass
113-119 A7 --- Env Environment ("cluster", "group" or "field")
--------------------------------------------------------------------------------
Note (1): All galaxies with EW-Hb,e and EW-O2 measurements that are less than
2σ are replaced by the 1σ upper limits.
Note (2): No entry for a given line indicates that the specified feature
did not fall in the wavelength range of the spectrum.
Note (3): All galaxies with EW-Hb,e measurements that are less than
2σ are replaced by the 1σ upper limits.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 02-Jul-2018