Efficacy of early stellar feedback in low gas surface density environments. Issue 2 (4th November 2019)

• Record Type: Journal Article
• Authors: Kannan, Rahul; Marinacci, Federico; Simpson, Christine M; Glover, Simon C O; Hernquist, Lars
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 491:Issue 2(2020)
• Page Start: 2088
• Page End: 2103
• Publication Date: 2019-11-04
• Subjects: radiative transfer -- methods: numerical -- ISM: structure -- galaxies: ISM; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stz3078
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We present a suite of high-resolution radiation hydrodynamic simulations of a small patch (1 kpc 2 ) 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.