Stellar Population Properties of ETGs in Compact Groups of Galaxies

Abstract

We present results on the study of the stellar population in Early-Type galaxies (ETGs) belonging to 151 Compact Groups (CGs). We also selected a field sample composed of 846 ETGs to investigate environmental effects on galaxy evolution. We find that the dependences of mean stellar ages, [Z/H] and [$\alpha$/Fe] on central stellar velocity dispersion are similar, regardless where the ETG resides, CGs or field. When compared to the sample of centrals and satellites from the literature, we find that ETGs in GCs behave similarly to centrals, especially those embedded in low-mass haloes ($M_h<10^{12.5}{M}_{\odot }$). Except for the low-mass limit, where field galaxies present a Starforming signature, not seen in CGs, the ionization agent of the gas in CG and field galaxies seem to be similar and due to hot, evolved low-mass stars. However, field ETGs present an excess of H$\alpha$ emission relative to ETGs in CGs. Additionally, we performed a dynamical analysis, which shows that CGs present a bimodality in the group velocity dispersion distribution - a high and low-$\sigma$ mode. Our results indicate that high-$\sigma$ groups have a smaller fraction of spirals, shorter crossing times, and a more luminous population of galaxies than the low $\sigma$ groups. It is important to emphasize that our findings point to a small environmental impact on galaxies located in CGs. The only evidence we find is the change in gas content, suggesting environmentally-driven gas loss.

21 pages, 18 Figures

References in corpus (16)

• The Host Galaxies and Classification of Active Galactic Nuclei
• Astrophysics Source Code Library
• Galaxy Groups in the SDSS DR4: I. The Catalogue and Basic Properties
• Evolutionary Stellar Population Synthesis with MILES. Part I: The Base Models and a New Line Index System
• Galaxy Zoo 1 : Data Release of Morphological Classifications for nearly 900,000 galaxies
• On the frequency, intensity and duration of starburst episodes triggered by galaxy interactions and mergers
• Methods for Rapidly Processing Angular Masks of Next-Generation Galaxy Surveys
• The Distribution of AGN in Clusters of Galaxies
• Compact groups in theory and practice - III. Compact groups of galaxies in the Sixth Data Release of the Sloan Digital Sky Survey
• SPIDER X - Environmental effects in central and satellite early-type galaxies through the stellar fossil record
• Truncated Star Formation in Compact Groups of Galaxies: A Stellar Population Study
• The AMIGA sample of isolated galaxies. XI. Optical characterisation of nuclear activity
• Investigating the Relation between Galaxy Properties and the Gaussianity of the Velocity Distribution of Groups and Clusters
• The Revealing Dust: Mid-Infrared Activity in Hickson Compact Group Galaxy Nuclei
• Deficiency of Broad Line AGNs in Compact Groups of Galaxies
• Group galaxy number density profiles far out: is the 'one-halo' term NFW out to $>10$ virial radii?

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