Examining the Role of Environment in a Comprehensive Sample of Compact Groups

Abstract

(Abridged) Compact groups, with their high number densities, small velocity dispersions, and an interstellar medium that has not been fully processed, provide a local analog to conditions of galaxy interactions in the earlier universe. The frequent and prolonged gravitational encounters that occur in compact groups affect the evolution of the constituent galaxies in a myriad of ways, for example gas processing and star formation. Recently, a statistically significant "gap" has been discovered mid-infrared IRAC colorspace of compact group galaxies. This gap is not seen in field samples and is a new example of how the compact group environment may affect the evolution of member galaxies. In order to investigate the origin and nature of this gap, we have compiled a sample of 49 compact groups. We find that a statistically significant deficit of galaxies in this gap region of IRAC colorspace is persistant in this sample, lending support to the hypothesis that the compact group environment inhibits moderate SSFRs. We note a curvature in the colorspace distribution, which is fully consistent with increasing dust temperature as the activity in a galaxy increases. This full sample of 49 compact groups allows us to subdivide the data according to physical properties of the groups. An analysis of these subsamples indicates that neither projected physical diameter nor density show a trend in colorspace within the values represented by this sample. We hypothesize that the apparent lack of a trend is due to the relatively small range of properties in this sample. Thus, the relative influence of stochastic effects becomes dominant. We analyze spectral energy distributions of member galaxies as a function of their location in colorspace and find that galaxies in different regions of MIR colorspace contain dust with varying temperatures and/or PAH emission.

24 pages, 13 figures. Accepted for publication in The Astronomical Journal

References in corpus (15)

• The Spitzer Local Volume Legacy: Survey Description and Infrared Photometry
• An Ultraviolet-to-Radio Broadband Spectral Atlas of Nearby Galaxies
• Star formation and AGN activity in SDSS cluster galaxies
• Witnessing galaxy preprocessing in the local Universe: the case of a star-bursting group falling into Abell 1367
• The Spitzer Spirals, Bridges, and Tails Interacting Galaxy Survey: Interaction-Induced Star Formation in the Mid-Infrared
• Powerful H${}_2$ Line-cooling in Stephan's Quintet : I - Mapping the Significant Cooling Pathways in Group-wide Shocks
• Galaxy Evolution in Hickson Compact Groups: The Role of Ram Pressure Stripping and Strangulation
• The Infrared Properties of Hickson Compact Groups
• Emerging Massive Star Clusters Revealed: High Resolution Imaging of NGC 4449 from the Radio to the Ultraviolet
• UV+IR Star Formation Rates: Hickson Compact Groups with Swift and Spitzer
• Mid-Infrared Evidence for Accelerated Evolution in Compact Group Galaxies
• Truncated Star Formation in Compact Groups of Galaxies: A Stellar Population Study
• Hierarchical Structure Formation and Modes of Star Formation in Hickson Compact Group 31
• The Revealing Dust: Mid-Infrared Activity in Hickson Compact Group Galaxy Nuclei
• Uncovering the Near-IR Dwarf Galaxy Population of the Coma Cluster with Spitzer IRAC

Cited by in corpus (29)

• The Suppression of Star Formation and the Effect of Galaxy Environment in Low-Redshift Galaxy Groups
• Enhanced Warm H2 Emission in the Compact Group Mid-Infrared "Green Valley"
• Strong Far-IR Cooling Lines, Peculiar CO Kinematics and Possible Star Formation Suppression in Hickson Compact Group 57
• Herschel observations of Hickson compact groups of galaxies: Unveiling the properties of cold dust
• The Optical Green Valley vs Mid-IR Canyon in Compact Groups
• Galaxy Interactions in Compact Groups II: abundance and kinematic anomalies in HCG 91c
• Catalogs of Compact Groups of Galaxies from the Enhanced SDSS DR12
• Intragroup and Galaxy-Linked Diffuse X-ray Emission in Hickson Compact Groups
• HI in Group Interactions: HCG 44
• The role of molecular gas in galaxy transition in compact groups
• Studying the evolution of galaxies in compact groups over the past 3 Gyr - II. The importance of environment in the suppression of star formation
• A $Chandra-Swift$ View of Point Sources in Hickson Compact Groups: High AGN fraction but a dearth of strong AGNs
• Stellar Populations in Compact Galaxy Groups: a Multi-Wavelength Study of HCGs 16, 22, and 42, their Star Clusters and Dwarf Galaxies
• Hierarchical Formation in Action: Characterizing Accelerated Galaxy Evolution in Compact Groups Using Whole-Sky WISE Data
• Some Like It Hot: Linking Diffuse X-ray Luminosity, Baryonic Mass, and Star Formation Rate in Compact Groups of Galaxies
• The Ultraviolet and Infrared Star Formation Rates of Compact Group Galaxies: An Expanded Sample
• The Fastest Galaxy Evolution in an Unbiased Compact Group Sample with WISE
• CO in Hickson Compact Group galaxies with enhanced warm \htwo\ emission: Evidence for galaxy evolution?
• Galaxy evolution in compact groups I: Revealing a transitional galaxy population through a multiwavelength approach
• Global Properties of Neutral Hydrogen in Compact Groups
• Exploring X-ray Binary Populations in Compact Group Galaxies with $Chandra$
• Comparing galaxy populations in compact and loose groups of galaxies III. Effects of environment on star formation
• Exploring the properties of low-frequency radio emission and magnetic fields in a sample of compact galaxy groups using the LOFAR Two-Metre Sky Survey (LoTSS)
• The Occurrence of Compact Groups of Galaxies Through Cosmic Time
• Cosmic Pathways for Compact Groups in the Milli-Millennium Simulation
• Compact groups of galaxies in GAMA -- Probing the densest minor systems at intermediate redshifts
• Somewhere in between: Tracing the Radio Emission from Galaxy Groups (or Why Does the Future of Observing Galaxy Groups with Radio Telescopes Look Promising?)
• Evolution of Galaxy Types and HI Gas in Hickson Compact Groups
• A Herschel and CARMA view of CO and [C II] in Hickson Compact groups