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The star formation main sequence and stellar mass assembly of galaxies in the Illustris simulation

Sparre, Martin and Hayward, Christopher C. and Springel, Volker and Vogelsberger, Mark and Genel, Shy and Torrey, Paul and Nelson, Dylan and Sijacki, Debora and Hernquist, Lars (2015) The star formation main sequence and stellar mass assembly of galaxies in the Illustris simulation. Monthly Notices of the Royal Astronomical Society, 447 (4). pp. 3548-3563. ISSN 0035-8711.

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Understanding the physical processes that drive star formation is a key challenge for galaxy formation models. In this paper, we study the tight correlation between the star formation rate (SFR) and stellar mass of galaxies at a given redshift, how halo growth influences star formation, and star formation histories of individual galaxies. We study these topics using Illustris, a state-of-the-art cosmological hydrodynamical simulation of galaxy formation. Illustris reproduces the observed relation (the star formation main sequence, SFMS) between SFR and stellar mass at redshifts z = 0 and 4, but at intermediate redshifts of z ≃ 1–2, the simulated SFMS has a significantly lower normalization than reported by observations. The scatter in the relation is consistent with the observed scatter. However, the fraction of outliers above the SFR–stellar mass relation in Illustris is less than that observed. Galaxies with halo masses of ∼10^12 M_⊙ dominate the SFR density of the Universe, in agreement with the results of abundance matching. Furthermore, more-massive galaxies tend to form the bulk of their stars at high redshift, which indicates that ‘downsizing’ occurs in Illustris. We also studied the star formation histories of individual galaxies, including the use of a principal component analysis decomposition. We find that for fixed stellar mass, galaxies that form earlier have more-massive black holes at z = 0, indicating that star formation and black hole growth are tightly linked processes in Illustris. While many of the properties of normal star-forming galaxies are well reproduced in the Illustris simulation, forming a realistic population of starbursts will likely require higher resolution and probably a more sophisticated treatment of star formation and feedback from stars and black holes.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Sparre, Martin0000-0002-9735-3851
Hayward, Christopher C.0000-0003-4073-3236
Springel, Volker0000-0001-5976-4599
Vogelsberger, Mark0000-0001-8593-7692
Genel, Shy0000-0002-3185-1540
Torrey, Paul0000-0002-5653-0786
Hernquist, Lars0000-0001-6950-1629
Additional Information:© 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2014 December 18. Received 2014 December 18; in original form 2014 August 28. First published online January 24, 2015. We thank Sune Toft, Peter Behroozi, Nicholas Lee and David Sanders for useful discussions. The Dark Cosmology Centre is funded by the Danish National Research Foundation. CCH is grateful to the Klaus Tschira Foundation and the Gordon and Betty Moore Foundation for financial support. VS acknowledges support by the European Research Council under ERC-StG EXAGAL-308037.
Funding AgencyGrant Number
Danish National Research FoundationUNSPECIFIED
Klaus Tschira FoundationUNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
European Research Council (ERC)EXAGAL-308037
Subject Keywords:methods: numerical; galaxies: evolution; galaxies: formation; galaxies: starburst; galaxies: star formation; cosmology: theory
Issue or Number:4
Record Number:CaltechAUTHORS:20150406-141422456
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Official Citation:Sparre, M., Hayward, C. C., Springel, V., Vogelsberger, M., Genel, S., Torrey, P., . . . Hernquist, L. (2015). The star formation main sequence and stellar mass assembly of galaxies in the Illustris simulation. Monthly Notices of the Royal Astronomical Society, 447(4), 3548-3563. doi: 10.1093/mnras/stu2713
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:56388
Deposited By: Jason Perez
Deposited On:07 Apr 2015 22:01
Last Modified:09 Mar 2020 13:19

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