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Title: GLOBAL PROPERTIES OF NEUTRAL HYDROGEN IN COMPACT GROUPS

Compact groups of galaxies provide a unique environment to study the evolution of galaxies amid frequent gravitational encounters. These nearby groups have conditions similar to those in the earlier universe when galaxies were assembled and give us the opportunity to witness hierarchical formation in progress. To understand how the compact group environment affects galaxy evolution, we examine the gas and dust in these groups. We present new single-dish GBT neutral hydrogen (H i) observations of 30 compact groups and define a new way to quantify the group H i content as the H i-to-stellar mass ratio of the group as a whole. We compare the H i content with mid-IR indicators of star formation and optical [g − r] color to search for correlations between group gas content and star formation activity of individual group members. Quiescent galaxies tend to live in H i-poor groups, and galaxies with active star formation are more commonly found in H i-rich groups. Intriguingly, we also find “rogue” galaxies whose star formation does not correlate with group H i content. In particular, we identify three galaxies (NGC 2968 in RSCG 34, KUG 1131+202A in RSCG 42, and NGC 4613 in RSCG 64) whose mid-IR activity ismore » discrepant with the H i. We speculate that this mismatch between mid-IR activity and H i content is a consequence of strong interactions in this environment that can strip H i from galaxies and abruptly affect star formation. Ultimately, characterizing how and on what timescales the gas is processed in compact groups will help us understand the interstellar medium in complex, dense environments similar to the earlier universe.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8]
  1. Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)
  2. Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States)
  3. Department of Physics and Astronomy, University of Western Ontario, London, ON (Canada)
  4. Departamento de Astronomía, Universidad de Concepción, Concepción (Chile)
  5. National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States)
  6. Physics Department, Austin College, Sherman, TX 75090 (United States)
  7. Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045 (United States)
  8. Department of Astronomy and Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)
Publication Date:
OSTI Identifier:
22520021
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (Online); Journal Volume: 151; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COLOR; COMPARATIVE EVALUATIONS; CORRELATIONS; COSMIC DUST; ENVIRONMENT; GALACTIC EVOLUTION; GALAXIES; HYDROGEN; INDICATORS; MASS; STAR EVOLUTION; STARS; UNIVERSE