TY - JOUR
T1 - Tidal Interactions and Mergers in Intermediate-redshift EDisCS Clusters
AU - Deger, Sinan
AU - Rudnick, Gregory
AU - Kelkar, Kshitija
AU - Aragón-Salamanca, Alfonso
AU - Desai, Vandana
AU - Lotz, Jennifer M.
AU - Jablonka, Pascale
AU - Moustakas, John
AU - Zaritsky, Dennis
N1 - Funding Information:
G.R. acknowledges funding support from HST program HST-GO-12590.011-A, HST-AR-12152.01-A, HST-AR-14310.001; NSF AST grants 1211358 and 1517815; and the NSF under award no. EPS-0903806, with matching support from the state of Kansas through Kansas Technology Enterprise Corporation. G.R. would also like to acknowledge the support of an Alexander von Humboldt Foundation fellowship for experienced researchers and the excellent hospitality of the Max-Planck-Institute for Astronomy, the University of Hamburg Observatory, the Max-Planck-Institute for Extraterrestrial Physics, the International Space Sciences Institute, and the European Southern Observatory, where some of this research was conducted.
PY - 2018/12/10
Y1 - 2018/12/10
N2 - We study the fraction of tidal interactions and mergers (TIMs) with well-identified observability timescales (f TIM) 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 f TIM using both a visual classification of galaxy morphologies and an automated method, the G - M 20 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 f TIM and z, in that higher z values correspond to higher f TIM. However, we also cannot rule out the null hypothesis of no correlation at higher than 68% confidence. No trend is present between f TIM and σ. We find that f TIM shows suggestive peaks in groups, and tentatively in clusters at R > 0.5 × R 200, implying that f TIM gets boosted in these intermediate-density environments. However, our analysis of the local densities of our cluster sample does not reveal a trend between f TIM 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 f TIM at the clusters.
AB - We study the fraction of tidal interactions and mergers (TIMs) with well-identified observability timescales (f TIM) 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 f TIM using both a visual classification of galaxy morphologies and an automated method, the G - M 20 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 f TIM and z, in that higher z values correspond to higher f TIM. However, we also cannot rule out the null hypothesis of no correlation at higher than 68% confidence. No trend is present between f TIM and σ. We find that f TIM shows suggestive peaks in groups, and tentatively in clusters at R > 0.5 × R 200, implying that f TIM gets boosted in these intermediate-density environments. However, our analysis of the local densities of our cluster sample does not reveal a trend between f TIM 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 f TIM at the clusters.
KW - galaxies: clusters: general
KW - galaxies: evolution
KW - galaxies: groups: general
KW - galaxies: interactions
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U2 - 10.3847/1538-4357/aaeb87
DO - 10.3847/1538-4357/aaeb87
M3 - Article
AN - SCOPUS:85058469752
VL - 869
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1
M1 - 6
ER -