Is there enough star formation in simulated protoclusters?
Name
2010.02259.pdf
Description
Accepted version
Size
3.42 MB
Format
Adobe PDF
Checksum (MD5)
da10fc54745db9bfa5cfdcdbe321b72d
Author(s)
Lim, Seunghwan
Scott, Douglas
Babul, Arif
Barnes, David J
Kay, Scott T
McCarthy, Ian G
Rennehan, Douglas
Vogelsberger, Mark
Date Issued
2020
Journal
Monthly Notices of the Royal Astronomical Society
Publisher
Oxford University Press (OUP)
Citation
Lim, Seunghwan, Scott, Douglas, Babul, Arif, Barnes, David J, Kay, Scott T et al. 2020. "Is there enough star formation in simulated protoclusters?." Monthly Notices of the Royal Astronomical Society, 501 (2).
Version
Author's final manuscript
Abstract
As progenitors of the most massive objects, protoclusters are key to tracing the evolution and star formation history of the Universe, and are responsible for ≳ 20 per cent of the cosmic star formation at z, > 2. Using a combination of state-of-the-art hydrodynamical simulations and empirical models, we show that current galaxy formation models do not produce enough star formation in protoclusters to match observations. We find that the star formation rates (SFRs) predicted from the models are an order of magnitude lower than what is seen in observations, despite the relatively good agreement found for their mass-accretion histories, specifically that they lie on an evolutionary path to become Coma-like clusters at z ≃ 0. Using a well-studied protocluster core at z = 4.3 as a test case, we find that star formation efficiency of protocluster galaxies is higher than predicted by the models. We show that a large part of the discrepancy can be attributed to a dependence of SFR on the numerical resolution of the simulations, with a roughly factor of 3 drop in SFR when the spatial resolution decreases by a factor of 4. We also present predictions up to z ≃ 7. Compared to lower redshifts, we find that centrals (the most massive member galaxies) are more distinct from the other galaxies, while protocluster galaxies are less distinct from field galaxies. All these results suggest that, as a rare and extreme population at high z, protoclusters can help constrain galaxy formation models tuned to match the average population at z ≃ 0.
MIT Department
Massachusetts Institute of Technology. Department of Physics
MIT Kavli Institute for Astrophysics and Space Research
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Attribution-NonCommercial-ShareAlike 4.0 International
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DOI of Published Version
https://doi.org/10.1093/MNRAS/STAA3693
