Efficacy of early stellar feedback in low gas surface density environments
Abstract
We present a suite of high-resolution radiation hydrodynamic simulations of a small patch (1 kpc2) of the interstellar medium (ISM) performed with AREPO-RT, with the aim to quantify the efficacy of various feedback processes like supernova (SN) explosions, photoheating, and radiation pressure in low gas surface density galaxies (Σgas ≃ 10 M⊙ pc-2). We show that radiative feedback decrease the star formation rate and therefore the total stellar mass formed by a factor of approximately two. This increases the gas depletion time-scale and brings the simulated Kennicutt-Schmidt relation closer to the observational estimates. Radiation feedback coupled with SN is more efficient at driving outflows with the mass and energy loading increasing by a factor of ∼10. This increase is mainly driven by the additional entrainment of medium-density (10-2 cm-3 ≤ n < 1 cm-3) warm (300 K ≤ T < 8000 K) material. Therefore, including radiative feedback tends to launch colder, denser, and more mass- and energy-loaded outflows. This is because photoheating of the high-density gas around a newly formed star overpressurizes the region, causing it to expand. This reduces the ambient density in which the SN explode by a factor of 10-100 which in turn increases their momentum output by a factor of ∼1.5-2.5. Finally, we note that in these low gas surface density environments, radiative feedback primarily impact the ISM via photoheating and radiation pressure has only a minimal role in regulating star formation.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- January 2020
- DOI:
- 10.1093/mnras/stz3078
- arXiv:
- arXiv:1812.01614
- Bibcode:
- 2020MNRAS.491.2088K
- Keywords:
-
- radiative transfer;
- methods: numerical;
- ISM: structure;
- galaxies: ISM;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 17 pages, 18 figures, Submitted to MNRAS