2006/09/18 by I. G. de la Rosa, R. R. de Carvalho, A. Vazdekis +1 · 1 citation
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Balmer series #Cosmology and Gravitation Theories #Elliptical galaxy #Emission spectrum #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Galaxy group #Lenticular galaxy #Physics #Population #Spectral line #Star formation #Stellar population #astro-ph
paper · pdf · doi:10.1086/509502
published as Astron.J.133:330-346,2007 · 18 pages, 9 figures. Accepted for publication in Astronomical Journal
arxiv created 2006/09/18 · openalex publication_date 2006/12/15 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present the results of a study comparing the stellar populations in the elliptical galaxies of Hickson compact groups (HCGs) with those in low-density environments. We analyze a sample of intermediate-resolution (4.25 Å FWHM) spectra of 22 galaxies in HCGs and 12 in the field or in loose groups. Three different population-synthesis models and stellar population analyses are used to make the results more robust. Great care has been taken to correct for the emission contamination of the Balmer lines, used to determine the mean luminosity-weighted ages of the galaxies. We find that, on average, galaxies in HCGs are systematically older and more metal-poor than in the field, in agreement with previous works. The most interesting finding is that the low-σ galaxies in HCGs show an enhanced [Mg/Fe] ratio and depleted metallicity [ Z /H] with respect to their counterparts in the field. This anomalous behavior is interpreted as evidence for the action of a mechanism that truncates the star formation (SF). Hydrodynamic simulations of galaxy mergers (Di Matteo et al. 2005) support this interpretation by predicting the quenching of SF soon after the merger event. Combining this scenario and the evidence presented here, the HCGs, generally considered to be ideal environments for galaxy-galaxy interactions, become ideal places for SF truncation.