Star-formation and stellar feedback recipes in galaxy evolution models
- Autor(en)
- Gerhard Hensler, Simone Recchi, Sylvia Ploeckinger, Matthias Kuehtreiber, Patrick Steyrleithner, Lei Liu
- Abstrakt
Modeling galaxy formation and evolution is critically depending on star formation (SF). Since cosmological and galaxy-scale simulations cannot resolve the spatial and density scales on which SF acts, a large variety of methods are developed and applied over the last decades. Nonetheless, we are still in the test phase how the choice of parameters affects the models and how they agree with observations.As a simple ansatz, recipes are based on power-law SF dependences on gas density as justified by gas cooling and collapse timescales. In order to prevent SF spread throughout the gas, temperature and density thresholds are also used, although gas dynamical effects, like e.g. gas infall, seem to trigger SF significantly.The formed stars influence their environment immediately by energetic and materialistic feedback. It has been experienced in numerical models that supernova typeII explosions act with a too long time delay to regulate the SF, but that winds and ionizing radiation by massive stars must be included. The implementation of feedback processes, their efficiencies and timescales, is still in an experimental state, because they depend also on the physical state of the surrounding interstellar medium (ISM).Combining a SF-gas density relation with stellar heating vs. gas cooling and taking the temperature dependence into account, we have derived an analytical expression of self-regulated SF which is free of arbitrary parameters. We have performed numerical models to study this recipe and different widely used SF criteria in both, particle and grid codes. Moreover, we compare the SF behavior between single-gas phase and multi-phase treatments of the ISM.Since dwarf galaxies (DGs) are most sensitive to environmental influences and contain only low SF rates, we explore two main affects on their models: 1. For external effects we compare SF rates of isolated and ram-pressure suffering DGs. Moreover, we find a SF enhancement in tidal-tail DGs by the compressive tidal field. 2. Because of locally low SF rates we compare the stellar feedback of a mostly assumed but only fractionally occupied stellar initial mass function with a bottom-heavy one.
- Organisation(en)
- Institut für Astrophysik
- Externe Organisation(en)
- Leiden University, Webster Vienna Private University, Chinese Academy of Sciences (CAS)
- Journal
- IAU General Assembly Meeting
- Band
- 22
- Publikationsdatum
- 08-2015
- Peer-reviewed
- Ja
- ÖFOS 2012
- 103004 Astrophysik
- Link zum Portal
- https://ucrisportal.univie.ac.at/de/publications/f495e545-93f5-4c0f-903e-0d13c6d2621e