2006/10/30 by Philippe Amram, P. Amram, Amram, Philippe +11
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #Electrical and Electromagnetic Research #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0610917
Comments: 9 pages, 1 figure, invited talk, in "Mapping the Galaxy and Nearby Galaxies," Ishigaki Japan, June 2006, eds. K. Wada & F. Combes
arxiv created 2006/10/30 · openalex publication_date 2006/10/30 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Nearby Compact Groups of Galaxies (CGs) are very complex systems, tracing their history is a challenge (e.g. Stephan's Quintet). The presence of a diffuse X-rays emission that often peaks in the center of CGs shows that CGs are bound structures, they show numerous signs of interaction but their lifetime in much longer than their crossing times. Hickson CGs clearly show different stages of evolution, from weakly interacting galaxies to merging systems. CGs infalling into clusters may provide a mechanism to form clusters at high redshifts (e.g. in A1367). Massive versions of today's CGs may have been the best candidate precursors of fossil groups. Do CGs mimic the high redshift universe? This is still an open question. Indeed, their high density and low velocity dispersion should induce a high interaction rate and fast merging, CGs are nevertheless long-lived structures. On the other hand, there is probably no (or a few) isolated CGs in the high z universe. CGs may fuel high z clusters, they may produce fossil groups and fossil ellipticals. CGs at high z are difficult to detect and are still to be discovered. Interpretation of distant kinematics of galaxies may need nearby sample of galaxies to disentangle beam-smearing from evolutionary effects (e.g. HCG 31). Beam smearing effects may bias the Tully-Fisher relation (shifted towards lower M/L).