Preprocessing among the Infalling Galaxy Population of EDisCS Clusters
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Author
Just, Dennis W.Kirby, Matthew
Zaritsky, Dennis
Rudnick, Gregory
Desjardins, Tyler
Cool, Richard
Moustakas, John
Clowe, Douglas
Lucia, Gabriella De
Aragón-Salamanca, Alfonso

Desai, Vandana

Finn, Rose
Halliday, Claire
Jablonka, Pascale
Mann, Justin
Poggianti, Bianca

Bian, Fu-Yan
Liebst, Kelley
Affiliation
Univ Arizona, Steward ObservUniv Arizona, Dept Phys
Univ Arizona, MMT Observ
Issue Date
2019-10-24
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IOP PUBLISHING LTDCitation
Dennis W. Just et al 2019 ApJ 885 6Journal
ASTROPHYSICAL JOURNALRights
Copyright © 2019. The American Astronomical Society. All rights reserved.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
We present results from a low-resolution spectroscopic survey for 21 galaxy clusters at 0.4 < z < 0.8 selected from the ESO Distant Cluster Survey. We measured spectra using the low-dispersion prism in IMACS on the Magellan Baade telescope and calculate redshifts with an accuracy of sigma(z) = 0.007. We find 1763 galaxies that are brighter than R = 22.9 in the large-scale cluster environs. We identify the galaxies expected to be accreted by the clusters as they evolve to z = 0 using spherical infall models and find that similar to 30%-70% of the z = 0 cluster population lies outside the virial radius at z similar to 0.6. For analogous clusters at z = 0, we calculate that the ratio of galaxies that have fallen into the clusters since z similar to 0.6 to those that were already in the core at that redshift is typically between similar to 0.3 and 1.5. This wide range of ratios is due to intrinsic scatter and is not a function of velocity dispersion, so a variety of infall histories is to be expected for clusters with current velocity dispersions of 300 km s(-1) less than or similar to sigma less than or similar to 1200 km s(-1). Within the infall regions of z similar to 0.6 clusters, we find a larger red fraction of galaxies than in the field and greater clustering among red galaxies than blue. We interpret these findings as evidence of "preprocessing," where galaxies in denser local environments have their star formation rates affected prior to their aggregation into massive clusters, although the possibility of backsplash galaxies complicates the interpretation.ISSN
0004-637XVersion
Final published versionSponsors
NASA LTSA award [NNG05GE82G]; NASA GALEX grant [NNX11AI47G]; European Research Council under European Community's Seventh Framework Programme (FP7/2007-2013)/ERC grant [202781]; Swiss National Science Foundation (SNSF)Swiss National Science Foundation (SNSF)ae974a485f413a2113503eed53cd6c53
10.3847/1538-4357/ab44a0