Modeling for Stellar Feedback in Galaxy Formation Simulations
Journal
The Astrophysical Journal
Journal Volume
836
Journal Issue
2
Start Page
204
ISSN
0004-637X
1538-4357
Date Issued
2017-02-20
Author(s)
Abstract
Various heuristic approaches to model unresolved supernova (SN) feedback in galaxy formation simulations exist to reproduce the formation of spiral galaxies and the overall inefficient conversion of gas into stars. Some models, however, require resolution-dependent scalings. We present a subresolution model representing the three major phases of supernova blast wave evolution-free expansion, energy-conserving Sedov-Taylor, and momentumconserving snowplow-with energy scalings adopted from high-resolution interstellar-medium simulations in both uniform and multiphase media. We allow for the effects of significantly enhanced SN remnant propagation in a multiphase medium with the cooling radius scaling with the hot volume fraction, fhot, as (1 - fhot)-4/5. We also include winds from young massive stars and AGB stars, Strömgren sphere gas heating by massive stars, and a mechanism that limits gas cooling that is driven by radiative recombination of dense H II regions. We present initial tests for isolated Milky Way-like systems simulated with the GADGET-based code SPHgal with improved SPH prescription. Compared to pure thermal SN input, the model significantly suppresses star formation at early epochs, with star formation extended both in time and space in better accord with observations. Compared to models with pure thermal SN feedback, the age at which half the stellar mass is assembled increases by a factor of 2.4, and the mass-loading parameter and gas outflow rate from the galactic disk increase by a factor of 2. Simulation results are converged for a variation of two orders of magnitude in particle mass in the range (1.3-130) × 104 solar masses.
Subjects
galaxies: abundances
galaxies: evolution
galaxies: formation
galaxies: stellar content
methods: numerical
Publisher
American Astronomical Society
Type
journal article