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Constraints on the star formation efficiency of galaxies during the epoch of reionization

Sun, G. and Furlanetto, S. R. (2016) Constraints on the star formation efficiency of galaxies during the epoch of reionization. Monthly Notices of the Royal Astronomical Society, 460 (1). pp. 417-433. ISSN 0035-8711. doi:10.1093/mnras/stw980.

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Reionization is thought to have occurred in the redshift range of 6 < z < 9, which is now being probed by both deep galaxy surveys and CMB observations. Using halo abundance matching over the redshift range 5 < z < 8 and assuming smooth, continuous gas accretion, we develop a model for the star formation efficiency f⋆ of dark matter haloes at z > 6 that matches the measured galaxy luminosity functions at these redshifts. We find that f⋆ peaks at ∼30 per cent at halo masses M ∼ 10^(11)–10^(12) M⊙, in qualitative agreement with its behaviour at lower redshifts. We then investigate the cosmic star formation histories and the corresponding models of reionization for a range of extrapolations to small halo masses. We use a variety of observations to further constrain the characteristics of the galaxy populations, including the escape fraction of UV photons. Our approach provides an empirically calibrated, physically motivated model for the properties of star-forming galaxies sourcing the epoch of reionization. In the case where star formation in low-mass haloes is maximally efficient, an average escape fraction ∼0.1 can reproduce the optical depth reported by Planck, whereas inefficient star formation in these haloes requires either about twice as many UV photons to escape, or an escape fraction that increases towards higher redshifts. Our models also predict how future observations with James Webb Space Telescope can improve our understanding of these galaxy populations.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Sun, G.0000-0003-4070-497X
Furlanetto, S. R.0000-0002-0658-1243
Additional Information:© 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2016 April 21. Received 2016 April 21; in original form 2015 December 8. First published online April 26, 2016. The authors would like to thank the anonymous referee, as well as Richard Ellis, Phil Hopkins, Yu Lu, Jordan Mirocha, and Brant Robertson for extremely helpful comments on the manuscript. GS also thanks Jamie Bock for his kind support and Jianfei Shen for discussions of the statistical inference. This research was completed as part of the University of California Cosmic Dawn Initiative. We acknowledge support from the University of California Office of the President Multicampus Research Programs and Initiatives through award MR-15-328388. SRF was partially supported by NASA grant NNX15AK80G, administered through the ATP programme, and by a Simons Fellowship in Theoretical Physics. SRF also thanks the Observatories of the Carnegie Institute of Washington for hospitality while much of this work was completed.
Funding AgencyGrant Number
University of CaliforniaMR-15-328388
Simons FoundationUNSPECIFIED
Subject Keywords:galaxies: evolution – galaxies: high-redshift – early Universe
Issue or Number:1
Record Number:CaltechAUTHORS:20160818-094815889
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Official Citation:G. Sun and S. R. Furlanetto Constraints on the star formation efficiency of galaxies during the epoch of reionization MNRAS (July 21, 2016) Vol. 460 417-433 doi:10.1093/mnras/stw980 first published online April 26, 2016
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:69750
Deposited By: Tony Diaz
Deposited On:18 Aug 2016 18:34
Last Modified:11 Nov 2021 04:19

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