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Thermal Regulation and the Star-forming Main Sequence

Steinhardt, Charles L. and Jermyn, Adam S. and Lodman, Jackie (2020) Thermal Regulation and the Star-forming Main Sequence. Astrophysical Journal, 890 (1). Art. No. 19. ISSN 1538-4357.

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We argue that the interplay between cosmic rays, the initial mass function (IMF), and star formation plays a crucial role in regulating the star-forming "main sequence." To explore these phenomena we develop a toy model for galaxy evolution in which star formation is regulated by a combination of a temperature-dependent IMF and heating due to starlight, cosmic rays, and (at very high redshift) the cosmic microwave background. This produces an attractor, near-equilibrium solution which is consistent with observations of the star-forming main sequence over a broad redshift range. Additional solutions to the same equations may correspond to other observed phases of galaxy evolution, including quiescent galaxies. This model makes several falsifiable predictions, including higher metallicities and dust masses than anticipated at high redshift and isotopic abundances in the Milky Way. It also predicts that stellar mass-to-light ratios are lower than produced using a Milky Way–derived IMF, such that inferences of stellar masses and star formation rates for high redshift galaxies are overestimated. In some cases, this may also transform inferred dark matter profiles from core-like to cusp-like.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Steinhardt, Charles L.0000-0003-3780-6801
Jermyn, Adam S.0000-0001-5048-9973
Lodman, Jackie0000-0003-0923-9440
Additional Information:© 2020. The American Astronomical Society. Received 2019 October 31; revised 2019 December 23; accepted 2019 December 30; published 2020 February 7. The authors thank Iryna Butsky, Daniel Ceverino, Kristian Finlator, Vasily Kokorev, Adrian Lopez, and Georgios Magdis for helpful discussions. C.L.S. is supported by ERC grant 648179 "ConTExt." The Cosmic Dawn Center (DAWN) is funded by the Danish National Research Foundation under grant No. 140. A.S.J. thanks the UK Marshall commission and the Flatiron Institute of the Simons Foundation for financial support. Support for J.L. by the Rose Hills Foundation is appreciated. This research was supported in part by the National Science Foundation under grant No. NSF PHY-1748958, and by the Gordon and Betty Moore Foundation through Grant GBMF7392.
Funding AgencyGrant Number
European Research Council (ERC)648179
Danish National Research Foundation140
Marshall CommissionUNSPECIFIED
Flatiron InstituteUNSPECIFIED
Rose Hills FoundationUNSPECIFIED
Gordon and Betty Moore FoundationGBMF7392
Subject Keywords:Star formation ; Galaxy evolution ; Initial mass function ; Cosmic rays ; Cosmic ray sources ; Cosmic microwave background radiation
Issue or Number:1
Classification Code:Unified Astronomy Thesaurus concepts: Star formation (1569); Galaxy evolution (594); Initial mass function (796); Cosmic rays (329); Cosmic ray sources (328); Cosmic microwave background radiation (322)
Record Number:CaltechAUTHORS:20200207-102105337
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Official Citation:Charles L. Steinhardt et al 2020 ApJ 890 19
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:101184
Deposited By: George Porter
Deposited On:10 Feb 2020 15:37
Last Modified:10 Feb 2020 15:37

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