The global star formation law by supernova feedback

Journal Article · Mon Jul 15 00:00:00 EDT 2019 · Monthly Notices of the Royal Astronomical Society

DOI:https://doi.org/10.1093/mnras/stz1919· OSTI ID:1564329

Dekel, Avishai ^[1]; Sarkar, Kartick C.  ^[2]; Jiang, Fangzhou  ^[2]; Bournaud, Frederic ^[3]; Krumholz, Mark R.  ^[4]; Ceverino, Daniel ^[5]; Primack, Joel R. ^[6]

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1. Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel, SCIPP, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
2. Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel
3. Laboratoire AIM Paris-Saclay, CEA/IRFU/SAp, Universite Paris Diderot, F-91191 Gif-sur-Yvette Cedex, France
4. Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2612, Australia
5. Cosmic Dawn Center (DAWN), Niels Bohr Institute, University of Copenhagen, Vibenshuset, Lyngbyvej 2, DK-2100 Copenhagen, Denmark
6. Physics Department, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA

ABSTRACT We address a simple model where the Kennicutt–Schmidt (KS) relation between the macroscopic densities of star formation rate (SFR, ρsfr) and gas (n) in galactic discs emerges from self-regulation of the SFR via supernova feedback. It arises from the physics of supernova bubbles, insensitive to the microscopic SFR recipe and not explicitly dependent on gravity. The key is that the filling factor of SFR-suppressed supernova bubbles self-regulates to a constant, f ∼ 0.5. Expressing the bubble fading radius and time in terms of n, the filling factor is $$f\propto S\, n^{-s}$$ with s ≃ 1.5, where S is the supernova rate density. A constant f thus refers to ρsfr ∝ n1.5, with a density-independent SFR efficiency per free-fall time ∼0.01. The self-regulation to f ∼ 0.5 and the convergence to a KS relation independent of the local SFR recipe are demonstrated in cosmological and isolated-galaxy simulations using different codes and recipes. In parallel, the spherical analysis of bubble evolution is generalized to clustered supernovae, analytically and via simulations, yielding s ≃ 1.5 ± 0.5. An analysis of photoionized bubbles about pre-supernova stars yields a range of KS slopes but the KS relation is dominated by the supernova bubbles. Superbubble blowouts may lead to an alternative self-regulation by outflows and recycling. While the model is oversimplified, its simplicity and validity in the simulations may argue that it captures the origin of the KS relation.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
• Sponsoring Organization: USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR); National Science Foundation (NSF); National Aeronautics and Space Administration (NASA)
• Grant/Contract Number: AST-1405962
• OSTI ID: 1564329
• Alternate ID(s): OSTI ID: 1577796
• Report Number(s): arXiv:1903.00962v1
• Journal Information: Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Vol. 488 Journal Issue: 4; ISSN 0035-8711
• Publisher: Royal Astronomical Society
• Country of Publication: United Kingdom
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
stars: formation
supernovae
general
galaxies: evolution
galaxies: formation
galaxies: ISM