Pontzen, A;
Tremmel, M;
Roth, N;
Peiris, HV;
Saintonge, A;
Volonteri, M;
Quinn, T;
(2017)
How to quench a galaxy.
Monthly Notices of the Royal Astronomical Society
, 465
(1)
pp. 547-558.
10.1093/mnras/stw2627.
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Abstract
We show how the interplay between active galactic nuclei (AGNs) and merger history determines whether a galaxy quenches star formation (SF) at high redshift. We first simulate, in a full cosmological context, a galaxy of total dynamical mass Mvir = 1012 M⊙ at z = 2. Then we systematically alter the accretion history of the galaxy by minimally changing the linear overdensity in the initial conditions. This ‘genetic modification’ approach allows the generation of three sets of Λ CDM initial conditions leading to maximum merger ratios of 1:10, 1:5 and 2:3, respectively. The changes leave the final halo mass, large-scale structure and local environment unchanged, providing a controlled numerical experiment. Interaction between the AGN physics and mergers in the three cases leads, respectively, to a star-forming, temporarily quenched and permanently quenched galaxy. However, the differences do not primarily lie in the black hole accretion rates, but in the kinetic effects of the merger: the galaxy is resilient against AGN feedback unless its gaseous disc is first disrupted. Typical accretion rates are comparable in the three cases, falling below 0.1 M⊙ yr−1, equivalent to around 2 per cent of the Eddington rate or 10−3 times the pre-quenching star formation rate, in agreement with observations. This low level of black hole accretion can be sustained even when there is insufficient dense cold gas for SF. Conversely, supernova feedback is too distributed to generate outflows in high-mass systems, and cannot maintain quenching over periods longer than the halo gas cooling time.
| Type: | Article |
|---|---|
| Title: | How to quench a galaxy |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/stw2627 |
| Publisher version: | http://dx.doi.org/10.1093/mnras/stw2627 |
| Language: | English |
| Additional information: | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society © 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. |
| Keywords: | Science & Technology, Physical Sciences, Astronomy & Astrophysics, galaxies: evolution, galaxies: star formation, galaxies: stellar content, STAR-FORMATION RATE, ACTIVE GALACTIC NUCLEI, BLACK-HOLE ACCRETION, DARK-MATTER HALOES, SIMILAR-TO 2, INTEGRAL FIELD SPECTROSCOPY, KILOPARSEC-SCALE OUTFLOWS, M-ASTERISK RELATION, QUIESCENT GALAXIES, FORMING GALAXIES |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1508534 |
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