Efficacy of early stellar feedback in low gas surface density environments

Rahul Kannan; Federico Marinacci; Christine M. Simpson; Simon C. O. Glover; Lars Hernquist

doi:10.1093/mnras/stz3078

paper

Efficacy of early stellar feedback in low gas surface density environments

arXiv:1812.01614 · doi:10.1093/mnras/stz3078

Abstract

We present a suite of high resolution radiation hydrodynamic simulations of a small patch ( $1 kpc^{2}$ ) of the inter-stellar medium (ISM) performed with Arepo-RT, with the aim to quantify the efficacy of various feedback processes like supernovae explosions (SNe), photoheating and radiation pressure in low gas surface density galaxies ( $Σ_{gas} ≃ 10 M_{⊙} pc^{- 2}$ ). We show that radiation fields decrease the star formation rate and therefore the total stellar mass formed by a factor of $\sim 2$ . This increases the gas depletion timescale and brings the simulated Kennicutt-Schmidt relation closer to the observational estimates. Radiation feedback coupled with SNe is more efficient at driving outflows with the mass and energy loading increasing by a factor of $\sim 10$ . This increase is mainly driven by the additional entrainment of medium density ( $1 0^{- 2} \leq n < 1 cm^{- 3}$ ), warm ( $300 K \leq T < 8000 K$ ) material. Therefore including radiation fields tends to launch colder, denser and higher mass and energy loaded outflows. This is because photoheating of the high density gas around a newly formed star over-pressurises the region, causing it to expand. This reduces the ambient density in which the SNe explode by a factor of $10 - 100$ which in turn increases their momentum output by a factor of $\sim 1.5 - 2.5$ . Finally, we note that in these low gas surface density environments, radiation fields primarily impact the ISM via photoheating and radiation pressure has only a minimal role in regulating star formation.

arXiv comment17 pages, 18 figures, Submitted to MNRAS

Efficacy of early stellar feedback in low gas surface density environments

Abstract

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