English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We perform a comprehensive estimate of the frequency of galaxy mergers andtheir 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, thevisually-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 rangefrom 1.1% to 3.5%, and 3.6% to 7.5%, respectively. This is the firstapproximate empirical estimate of the frequency of minor mergers at z<1. For avisibility timescale of ~0.5 Gyr, it follows that over T_b~3--7 Gyr, ~68% ofhigh 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 asuite of Lambda CDM-based models: halo occupation distribution models,semi-analytic models, and hydrodynamic SPH simulations. We find qualitativeagreement between observations and models such that the (major+minor) mergerfraction or rate from different models bracket the observations, and show afactor of five dispersion. Near-future improvements can now start to rule outcertain merger scenarios. (3) Among ~3698 M*>=1e9 Msun galaxies, we find thatthe mean SFR of visibly merging systems is only modestly enhanced compared tonon-interacting galaxies over z~0.24--0.80. Visibly merging systems onlyaccount for less than 30% of the cosmic SFR density over T_b~3--7 Gyr. Thissuggests that the behavior of the cosmic SFR density over the last 7 Gyr ispredominantly shaped by non-interacting galaxies.

History of Galaxy Interactions and their Impact on Star Formation over the Last 7 Gyr from GEMS