CaltechAUTHORS
Published November 1, 2019 | Version Published + Accepted Version
Journal Article Open

Preprocessing among the Infalling Galaxy Population of EDisCS Clusters

Creators

  • 1. ROR icon University of Arizona
  • 2. ROR icon University of Toronto
  • 3. ROR icon University of Kansas
  • 4. ROR icon Siena College
  • 5. ROR icon Ohio University
  • 6. ROR icon Trieste Astronomical Observatory
  • 7. ROR icon University of Nottingham
  • 8. ROR icon Infrared Processing and Analysis Center
  • 9. ROR icon Galaxies, Etoiles, Physique et Instrumentation
  • 10. ROR icon École Polytechnique Fédérale de Lausanne
  • 11. ROR icon European Southern Observatory
  • 12. ROR icon Arizona State University

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 σ 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 ~30%–70% of the z = 0 cluster population lies outside the virial radius at z ~ 0.6. For analogous clusters at z = 0, we calculate that the ratio of galaxies that have fallen into the clusters since z ~ 0.6 to those that were already in the core at that redshift is typically between ~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 ≾ σ ≾ 1200 km s⁻¹. Within the infall regions of z ~ 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.

Additional Information

© 2019 The American Astronomical Society. Received 2018 September 4; revised 2019 September 5; accepted 2019 September 12; published 2019 October 24. We thank an anonymous referee for insightful comments that have improved the content and presentation of this paper. D.W.J. and D.Z. acknowledge financial support from NASA LTSA award NNG05GE82G and GALEX grant NNX11AI47G. G.D.L. acknowledges financial support from the European Research Council under European Community's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement No. 202781. P.J. acknowledges support by the Swiss National Science Foundation (SNSF).

Attached Files

Published - Just_2019_ApJ_885_6.pdf

Accepted Version - 1506.02051.pdf

Files

1506.02051.pdf

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Additional details

Identifiers

Eprint ID
99478
Resolver ID
CaltechAUTHORS:20191028-081952139

Related works

Describes
https://arxiv.org/abs/1506.02051 (URL)

Funding

NASA
NNG05GE82G
NASA
NNX11AI47G
European Research Council (ERC)
202781
Swiss National Science Foundation (SNSF)

Dates

Created
2019-10-28
Created from EPrint's datestamp field
Updated
2021-11-16
Created from EPrint's last_modified field

Caltech Custom Metadata

Caltech groups
Infrared Processing and Analysis Center (IPAC)