History of Galaxy Interactions and their Impact on Star Formation over the Last 7 Gyr from GEMS
| Autor: | Jogee, Shardha, Miller, Sarah H., Penner, Kyle, Skelton, Rosalind E., Conselice, Christopher J., Somerville, Rachel S., Bell, Eric F., Zheng, Xian Zhong, Rix, Hans-Walter, Robaina, Aday R., Barazza, Fabio D., Barden, Marco, Borch, Andrea, Beckwith, Steven V. W., Caldwell, John A. R., Peng, Chien Y., Heymans, Catherine, McIntosh, Daniel H., Haussler, Boris, Jahnke, Knud, Meisenheimer, Klaus, Sanchez, Sebastian F., Wisotzki, Lutz, Wolf, Christian, Papovich, Casey |
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| Rok vydání: | 2009 |
| Předmět: | |
| Zdroj: | Astrophys.J.697:1971-1992,2009 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1088/0004-637X/697/2/1971 |
| Popis: | We perform a comprehensive estimate of the frequency of galaxy mergers and their impact on star formation over z~0.24--0.80 (lookback time T_b~3--7 Gyr) using 3698 (M*>=1e9 Msun) galaxies with GEMS HST, COMBO-17, and Spitzer data. Our results are: (1) Among 790 high mass (M*>=2.5e10 Msun) galaxies, the visually-based merger fraction over z~0.24--0.80, ranges from 9%+-5% to 8%+-2%. Lower limits on the major and minor merger fractions over this interval range from 1.1% to 3.5%, and 3.6% to 7.5%, respectively. This is the first approximate empirical estimate of the frequency of minor mergers at z<1. For a visibility timescale of ~0.5 Gyr, it follows that over T_b~3--7 Gyr, ~68% of high mass systems have undergone a merger of mass ratio >1/10, with ~16%, 45%, and 7% of these corresponding respectively to major, minor, and ambiguous `major or minor' mergers. The mean merger rate is a few x 1e-4 Gyr-1 Mpc-3. (2) We compare the empirical merger fraction and rate for high mass galaxies to a suite of Lambda CDM-based models: halo occupation distribution models, semi-analytic models, and hydrodynamic SPH simulations. We find qualitative agreement between observations and models such that the (major+minor) merger fraction or rate from different models bracket the observations, and show a factor of five dispersion. Near-future improvements can now start to rule out certain merger scenarios. (3) Among ~3698 M*>=1e9 Msun galaxies, we find that the mean SFR of visibly merging systems is only modestly enhanced compared to non-interacting galaxies over z~0.24--0.80. Visibly merging systems only account for less than 30% of the cosmic SFR density over T_b~3--7 Gyr. This suggests that the behavior of the cosmic SFR density over the last 7 Gyr is predominantly shaped by non-interacting galaxies. Comment: Accepted for Publication in the Astrophysical Journal. 17 pages of text, 21 figures, 3 tables. Uses emulateapj5.sty |
| Databáze: | arXiv |
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