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Supernova feedback in numerical simulations of galaxy formation: separating physics from numerics

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Smith, Matthew C 
Shen, Sijing 

Abstract

While feedback from massive stars exploding as supernovae (SNe) is thought to be one of the key ingredients regulating galaxy formation, theoretically it is still unclear how the available energy couples to the interstellar medium and how galactic scale outflows are launched. We present a novel implementation of six sub-grid SN feedback schemes in the moving-mesh code Arepo, including injections of thermal and/or kinetic energy, two parametrizations of delayed cooling feedback and a `mechanical' feedback scheme that injects the correct amount of momentum depending on the relevant scale of the SN remnant resolved. All schemes make use of individually time-resolved SN events. Adopting isolated disk galaxy setups at different resolutions, with the highest resolution runs reasonably resolving the Sedov-Taylor phase of the SN, we aim to find a physically motivated scheme with as few tunable parameters as possible. As expected, simple injections of energy overcool at all but the highest resolution. Our delayed cooling schemes result in overstrong feedback, destroying the disk. The mechanical feedback scheme is efficient at suppressing star formation, agrees well with the Kennicutt-Schmidt relation and leads to converged star formation rates and galaxy morphologies with increasing resolution without fine tuning any parameters. However, we find it difficult to produce outflows with high enough mass loading factors at all but the highest resolution, indicating either that we have oversimplified the evolution of unresolved SN remnants, require other stellar feedback processes to be included, require a better star formation prescription or most likely some combination of these issues.

Description

Keywords

astro-ph.GA, astro-ph.GA

Journal Title

Monthly Notices of the Royal Astronomical Society

Conference Name

Journal ISSN

1365-2966
1365-2966

Volume Title

478

Publisher

Oxford University Press
Sponsorship
Science and Technology Facilities Council (ST/L000725/1)
European Research Council (638707)
Science and Technology Facilities Council (ST/N000927/1)
Science and Technology Facilities Council (ST/S002626/1)
Science and Technology Facilities Council (ST/P002315/1)
Science and Technology Facilities Council (ST/R002452/1)
Science and Technology Facilities Council (ST/R00689X/1)