2008/02/26 by S. Jogee, Shardha Jogee, Jogee, S. +61 · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #FOS: Physical sciences #Radio Astronomy Observations and Technology #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.0802.3901
To appear in Proceedings of "Formation and Evolution of Galaxy Disks", held in Rome, 1-5 October 2007. 4 pages, 4 figures. Uses asp2006.sty, graphicx.sty psfig.sty
arxiv created 2008/02/26 · openalex publication_date 2008/02/26 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We explore the history and impact of galaxy mergers and interactions over z~0.24 to 0.80, based on HST ACS, Combo-17, and Spitzer 24 mu data of ~4500 galaxies in the GEMS survey. Using visual and quantitative parameters,we identify galaxies with strong distortions indicative of recent strong interactions and mergers versus normal galaxies (E/S0, Sa, Sb-Sc, Sd/Irr). Our results are: (1) The observed fraction F of strongly disturbed systems among high mass (M>=2.5E10 Msun) galaxies is ~9% to 12% in every Gyr bin over z~0.24 to 0.80. The corresponding merger rate is a few times 10-4 galaxies Gyr-1 Mpc-3. The fraction F shows fair agreement with the merger fraction of mass ratio >=1:10 predicted by several LCDM-based simulations. (2) For M>=1E9 Msun systems, the average star formation rate (SFR) of strongly disturbed systems is only modestly enhanced with respect to normal galaxies, in agreement with recent simulations. In fact, over z~0.24 to 0.80, strongly disturbed systems only account for a small fraction (<~30%) of the total SFR density. This suggests that the behaviour of the cosmic SFR density over the last seven billion years is predominantly shaped by normal galaxies.