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Tidal Interactions and Mergers in Intermediate-redshift EDisCS Clusters

Deger, Sinan and Rudnick, Gregory and Kelkar, Kshitija and Aragón-Salamanca, Alfonso and Desai, Vandana and Lotz, Jennifer M. and Jablonka, Pascale and Moustakas, John and Zaritsky, Dennis (2018) Tidal Interactions and Mergers in Intermediate-redshift EDisCS Clusters. Astrophysical Journal, 869 (1). Art. No. 6. ISSN 1538-4357.

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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.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Deger, Sinan0000-0003-1943-723X
Rudnick, Gregory0000-0001-5851-1856
Aragón-Salamanca, Alfonso0000-0001-8215-1256
Desai, Vandana0000-0002-1340-0543
Lotz, Jennifer M.0000-0003-3130-5643
Zaritsky, Dennis0000-0002-5177-727X
Additional Information:© 2018. The American Astronomical Society. Received 2018 February 9; revised 2018 September 17; accepted 2018 September 26; published 2018 December 5. 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.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
NASA Hubble FellowshipHST-GO-12590.011-A
NASA Hubble FellowshipHST-AR-12152.01-A
NASA Hubble FellowshipHST-AR-14310.001
Kansas Technology Enterprise CorporationUNSPECIFIED
Alexander von Humboldt FoundationUNSPECIFIED
Subject Keywords:galaxies: clusters: general; galaxies: evolution; galaxies: groups: general; galaxies: interactions
Issue or Number:1
Record Number:CaltechAUTHORS:20181205-114248838
Persistent URL:
Official Citation:Sinan Deger et al 2018 ApJ 869 6
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:91507
Deposited By: George Porter
Deposited On:05 Dec 2018 21:31
Last Modified:03 Oct 2019 20:35

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