Astrophys. J., 869, 6-6 (2018/December-2)
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. and ZARITSKY D.
Abstract (from CDS):
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 > 0.5 x R200, 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.
© 2018. The American Astronomical Society. All rights reserved.
galaxies: clusters: general - galaxies: evolution - galaxies: groups: general - galaxies: interactions
Status at CDS:
// Examining the need for a new acronym. // Large table(s) of objects being ingested in VizieR.
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