Core formation in high-z massive haloes: heating by post-compaction satellites and response to AGN outflows
Abstract
Observed rotation curves in star-forming galaxies indicate a puzzling dearth of dark matter in extended flat cores within haloes of mass ≥10¹² M_⊙ at z ∼ 2. This is not reproduced by current cosmological simulations, and supernova-driven outflows are not effective in such massive haloes. We address a hybrid scenario where post-compaction merging satellites heat up the dark-matter cusps by dynamical friction, allowing active galactic nucleus (AGN)-driven outflows to generate cores. Using analytic and semi-analytic models (SatGen), we estimate the dynamical friction heating as a function of satellite compactness for a cosmological sequence of mergers. Cosmological simulations (VELA) demonstrate that satellites of initial virial masses >10^(11.3) M_⊙, which undergo wet compactions, become sufficiently compact for significant heating. Constituting a major fraction of the accretion on to haloes ≥10¹² M_⊙, these satellites heat up the cusps in half a virial time at z ∼ 2. Using a model for outflow-driven core formation (CuspCore), we demonstrate that the heated dark-matter cusps develop extended cores in response to removal of half the gas mass, while the more compact stellar systems remain intact. The mergers keep the dark matter hot, while the gas supply, fresh and recycled, is sufficient for the AGN outflows. AGNs indeed become effective in haloes ≥10¹² M_⊙, where the black hole growth is no longer suppressed by supernovae and its compaction-driven rapid growth is maintained by a hot circumgalactic medium. For simulations to reproduce the dynamical friction effects, they should resolve the compaction of the massive satellites and avoid artificial tidal disruption. AGN feedback could be boosted by clumpy black hole accretion and clumpy response to AGN.
Additional Information
© 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model) Accepted 2021 August 19. Received 2021 August 19; in original form 2021 June 1. We are grateful for stimulating interactions with Andrew Benson, Yohan Duboi, Pieter van Dokkum, Daisuke Nagai, Natascha Forster-Schreiber, Ian Smail, and Linda Tacconi. This work was partly supported by the grants Germany-Israel GIF I-1341-303.7/2016 (AD, AB), Germany-Israel DIP STE1869/2-1 GE625/17-1 (AD, RG, AB), ISF 861/20 (AD), ERC GreatDigInTheSky 834148 (JF), and a Troesh Scholarship (FJ). The cosmological VELA simulations were performed at the National Energy Research Scientific Computing Center (NERSC) at Lawrence Berkeley National Laboratory, and at NASA Advanced Supercomputing (NAS) at NASA Ames Research Center. Development and analysis have been performed in the astro cluster at HU. DATA AVAILABILITY. The codes used in this articles are available online, as referenced in the article and in the online supplementary material. Data and results underlying this article will be shared on reasonable request to the corresponding author.Attached Files
Published - stab2416.pdf
Submitted - 2106.01378.pdf
Supplemental Material - stab2416_supplemental_file.pdf
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Additional details
- Eprint ID
- 112473
- Resolver ID
- CaltechAUTHORS:20211215-621776000
- I-1341-303.7/2016
- German-Israeli Foundation for Research and Development
- DIP STE1869/2-1 GE625/17-1
- German-Israeli Foundation for Research and Development
- 861/20
- Israel Science Foundation
- 834148
- European Research Council (ERC)
- Troesh Family Distinguished Scholars Fund
- Created
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2021-12-16Created from EPrint's datestamp field
- Updated
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2021-12-16Created from EPrint's last_modified field
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- TAPIR