2011/03/09 by Hsin-Yi Shih, Alan Stockton
Engineering · Physics and Astronomy · #Accretion (finance) #Astronomy and Astrophysical Research #Compact group #Elliptical galaxy #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Peculiar galaxy #Red shift #Redshift #Space Technology and Applications #astro-ph.CO
paper · pdf · doi:10.1088/0004-637x/733/1/45
Accepted by ApJ
arxiv created 2011/03/09 · openalex publication_date 2011/05/03 · arxiv updated 2015/05/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
As part of a larger program to identify and characterize possible low-redshift analogs to massive compact red galaxies found at high redshift, we have examined the morphologies of three low-redshift compact galaxies drawn from the sample of Trujillo et al. Using deeper and higher resolution images, we have found faint and relatively extensive outer structures in addition to the compact cores identified in the earlier measurements. One object appears to have a small companion that may be involved in an ongoing minor merger of the sort that could be responsible for building up the outer parts of these galaxies. The ages of the dominant stellar populations in these objects are found to be around 2–4 Gyr, in good agreement with the previous estimates. The presence of diffuse outer structures in these galaxies indicates that truly compact and massive red galaxies are exceedingly rare at low redshift. The relatively young stellar populations suggest that the accretion of the extensive outer material must occur essentially universally on relatively short timescales of a few billion years or less. These results confirm and extend previous suggestions that the driving mechanism behind the size evolution of high-redshift compact galaxies cannot be highly stochastic processes such as major mergers, which would inevitably leave a non-negligible fraction of survivors at low redshift.