J/ApJ/869/6 Tidal interactions and mergers in EDisCS clusters (Deger+, 2018)
Tidal interactions and mergers in intermediate-redshift EDisCS clusters.
Deger S., Rudnick G., Kelkar K., Aragon-Salamanca A., Desai V., Lotz J.M.,
Jablonka P., Moustakas J., Zaritsky D.
<Astrophys. J., 869, 6 (2018)>
=2018ApJ...869....6D 2018ApJ...869....6D
ADC_Keywords: Clusters, galaxy; Redshifts; Velocity dispersion
Keywords: galaxies: clusters: general ; galaxies: evolution ;
galaxies: groups: general ; galaxies: interactions
Abstract:
We study the fraction of tidal interactions and mergers (TIMs) with
well-identified observability timescales (fTIM) in group, cluster,
and accompanying field galaxies and its dependence on redshift (z),
cluster velocity dispersion (σ), and environment analyzing
Hubble Space Telescope/ACS images and catalogs from the ESO Distant
Cluster Survey. Our sample consists of 11 clusters, seven groups, and
accompanying field galaxies at 0.4≤z≤0.8. We derive fTIM using
both a visual classification of galaxy morphologies and an automated
method, the G-M20 method. We calibrate this method using the visual
classifications that were performed on a subset of our sample. We find
marginal evidence for a trend between fTIM and z, in that higher z
values correspond to higher fTIM. However, we also cannot rule out
the null hypothesis of no correlation at higher than 68% confidence.
No trend is present between fTIM and σ. We find that fTIM
shows suggestive peaks in groups, and tentatively in clusters at
R>0.5xR200, implying that fTIM gets boosted in these
intermediate-density environments. However, our analysis of the local
densities of our cluster sample does not reveal a trend between fTIM
and density, except for a potential enhancement at the very highest
densities. We also perform an analysis of projected radius-velocity
phase space for our cluster members. Our results reveal that TIM and
undisturbed galaxies only have a 6% probability of having been drawn
from the same parent population in their velocity distribution and 37%
in radii, in agreement with the modest differences obtained in fTIM
at the clusters.
Description:
EDisCS (White+ 2005, J/A+A/444/365) is a detailed photometric and
spectroscopic survey of clusters, groups, and field galaxies, with
structures drawn from the Las Campanas Distant Cluster Survey
(Gonzalez+ 2001, J/ApJS/137/117). The EDisCS fields have either BVIK,
BVIJK, or VRIJK photometry depending on the redshift estimate of the
original cluster candidate. The sample was also observed with
extensive FORS2 spectroscopy on the Very Large Telescope (ESO;
Halliday+, 2004, J/A+A/427/397 and Milvang-Jensen+, 2008, J/A+A/482/419).
To study the morphological content of the EDisCS sample, we used HST
Advanced Camera for Surveys (ACS) imaging in the F814W filter (depths
of one orbit at cluster outskirts, five orbits at cluster core) of 10
of the highest-redshift clusters from Desai+ (2007, J/ApJ/660/1151).
We make use of these 10 fields with HST ACS images plus photometric
and spectroscopic catalogs for the analysis presented in this paper.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 44 17 The EDisCS-HST sample
table3.dat 65 264 Spectroscopic cluster & group members
table4.dat 54 398 Photometric cluster members
--------------------------------------------------------------------------------
See also:
VII/265 : COSMOS Morphological Catalog (V1.1) (Tasca+ 2009)
J/ApJ/496/39 : Properties of poor groups of galaxies. I. (Zabludoff+ 1998)
J/ApJ/542/673 : Morphological types of galaxies in clusters (Fasano+, 2000)
J/ApJS/137/117 : Las Campanas Distant Cluster Survey (LCDCS) (Gonzales+, 2001)
J/AJ/122/2205 : HDF-South K photometric redshift catalog (Rudnick+, 2001)
J/ApJ/588/218 : i*g* photometry of SDSS EDR galaxies (Abraham+, 2003)
J/ApJS/147/1 : Classification of nearby galaxies (Conselice+, 2003)
J/A+A/427/397 : Redshifts of 5 EDisCS galaxy clusters (Halliday+, 2004)
J/AJ/128/163 : Galaxy morphological classification (Lotz+, 2004)
J/A+A/444/365 : ESO Distant Cluster Survey, EDisCS (White+, 2005)
J/ApJ/660/1151 : Morphology of galaxies in 10 EDisCS clusters (Desai+, 2007)
J/A+A/482/419 : ESO Distant Cluster Survey, EDisCS. II (Milvang-Jensen+, 2008)
J/A+A/524/A6 : Evolution of spectral early-type galaxies (Saglia+, 2010)
J/ApJ/850/181 : Spectroscopic analysis of EDisCS clusters (Rudnick+, 2017)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- Set Cl=Cluster; G=Group
4- 16 A13 --- Field Structure name
17 A1 --- m_Field Component on structure name
19- 24 F6.4 --- z [0.4/0.8] Redshift
26- 29 I4 --- sigma [179/1080] Cluster velocity dispersion
31- 33 I3 --- e_sigma [26/110] Negative uncertainty on sigma
35- 37 I3 --- E_sigma [36/119] Positive uncertainty on sigma
39- 41 I3 --- Nph+sp [24/102]? Number of phot+spec members (1)
43- 44 I2 --- Nspec [2/36] Number of spectroscopically confirmed
members (1)
--------------------------------------------------------------------------------
Note (1): Numbers are given after quality cuts described in Section 2 are
applied.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 1 A1 --- Set [CGF] Subset: (C)luster or (G)roup member;
(F)ield Galaxy
3- 7 A5 --- --- [EDCSN]
8- 23 A16 --- EDCSN Galaxy ID (JHHMMSSs+DDMMSSs;
in Simbad)
25- 37 A13 --- Field Cluster or Field name
39- 44 F6.4 --- zspec [0.4/0.9] Galaxy Spectroscopic Redshift
46- 50 F5.2 [Msun] logM [10.4/11.8] Log10 Galaxy stellar mass
52- 55 F4.2 --- G [0.3/0.7] Galaxy Gini coefficient (G1)
57- 61 F5.2 --- M20 [-2.5/-0.7] Galaxy M20 value (G1)
63- 63 A1 --- Cl [TIMtim0] Visual Class (1)
65- 65 A1 --- f_Cl [*] *: changed the visual classification
by Kelkar+ (2017MNRAS.469.4551K 2017MNRAS.469.4551K)
--------------------------------------------------------------------------------
Note (1): Visual classes as follows:
M = Major merger (14 occurrences;
m = Minor merger (6 occurrences);
I = Strong interaction (15 occurrences);
i = Weak interaction (19 occurrences);
T = Strong tidal features (8 occurrences);
t = Mild tidal features (8 occurrences);
0 = undisturbed (194 occurrences).
See also Section 3.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 1 A1 --- Set [CF] Subset, (C)luster member or (F)ield galaxy
3- 7 A5 --- --- [EDCSN]
8- 23 A16 --- EDCSN Galaxy ID (JHHMMSSs+DDMMSSs)
25- 37 A13 --- Field Cluster or Field name
39- 43 F5.2 [Msun] logM [10.4/13.3] Log10 Galaxy stellar mass
45- 48 F4.2 --- G [0.3/1] Galaxy Gini coefficient (G1)
50- 54 F5.2 --- M20 [-2.6/-0.7] Galaxy M20 value (G1)
--------------------------------------------------------------------------------
Global notes:
Note (G1): The G value (Gini coefficient) and M20 value (second-order moment
of brightest 20% flux) after Lotz+ (2004, J/AJ/128/163).
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 31-Oct-2019