Abstract
We explore the galaxy-galaxy merger rate with the empirical model for galaxy formation, emerge. On average, we find that between 2 percent and 20 percent of massive galaxies (log(10)(m(*)/M-circle dot) >= 10.3) will experience a major merger per Gyr. Our model predicts galaxy merger rates that do not scale as a power law with redshift when selected by descendant stellar mass, and exhibit a clear stellar mass and mass-ratio dependence. Specifically, major mergers are more frequent at high masses and at low redshift. We show mergers are significant for the stellar mass growth of galaxies log(10)(m(*)/M-circle dot) greater than or similar to 11.0. For the most massive galaxies major mergers dominate the accreted mass fraction, contributing as much as 90 percent of the total accreted stellar mass. We reinforce that these phenomena are a direct result of the stellar-to-halo mass relation, which results in massive galaxies having a higher likelihood of experiencing major mergers than low-mass galaxies. Our model produces a galaxy pair fraction consistent with recent observations, exhibiting a form best described by a power-law exponential function. Translating these pair fractions into merger rates results in an inaccurate prediction compared to the model intrinsic values when using published observation time-scales. We find the pair fraction can be well mapped to the intrinsic merger rate by adopting an observation time-scale that decreases linearly with redshift as T-obs = -0.36(1 + z) + 2.39 [Gyr], assuming all observed pairs merge by z = 0.
| Dokumententyp: | Zeitschriftenartikel |
|---|---|
| Fakultät: | Physik |
| Themengebiete: | 500 Naturwissenschaften und Mathematik > 530 Physik |
| ISSN: | 0035-8711 |
| Sprache: | Englisch |
| Dokumenten ID: | 100932 |
| Datum der Veröffentlichung auf Open Access LMU: | 05. Jun. 2023, 15:36 |
| Letzte Änderungen: | 05. Jun. 2023, 15:36 |
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