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dc.contributor.authorRodríguez Montero, Francisco
dc.contributor.authorDavé, Romeel
dc.contributor.authorWild, Vivienne
dc.contributor.authorAnglés-Alcázar, Daniel
dc.contributor.authorNarayanan, Desika
dc.identifier.citationRodríguez Montero , F , Davé , R , Wild , V , Anglés-Alcázar , D & Narayanan , D 2019 , ' Mergers, starbursts, and quenching in the Simba simulation ' , Monthly Notices of the Royal Astronomical Society , vol. 490 , no. 2 , pp. 2139–2154 .
dc.identifier.otherPURE: 261094352
dc.identifier.otherPURE UUID: 259e6153-38ff-4c21-9db6-9fb9bca50f56
dc.identifier.otherBibCode: 2019arXiv190712680R
dc.identifier.otherScopus: 85079642494
dc.identifier.otherWOS: 000496926900049
dc.description.abstractWe use the Simbacosmological galaxy formation simulation to investigate the relationship between major mergers (≤ 4:1), starbursts, and galaxy quenching. Mergers are identified via sudden jumps in stellar mass M∗ well above that expected from in situ star formation, while quenching is defined as going from specific star formation rate sSFR>t−1H to sSFR<0.2t−1H, where tH is the Hubble time. At z≈0−3, mergers show ∼×2−3 higher SFR than a mass-matched sample of star-forming galaxies, but globally represent ≤1% of the cosmic SF budget. At low masses, the increase in SFR in mergers is mostly attributed to an increase in the H2 content, but for M∗≥1010.5M⊙ mergers also show an elevated star formation efficiency suggesting denser gas within merging galaxies. The merger rate for star-forming galaxies shows a rapid increase with redshift ∝(1+z)3.5, but the quenching rate evolves much more slowly, ∝(1+z)0.9; there are insufficient mergers to explain the quenching rate at z≤1.5. Simba first quenches galaxies at z≥3, with a number density in good agreement with observations. The quenching timescales τq are strongly bimodal, with `slow' quenchings (τq∼0.1tH) dominating overall, but `fast' quenchings (τq∼0.01tH) dominating in M∗∼1010−1010.5M⊙ galaxies, likely induced by Simba's jet-mode black hole feedback. The delay time distribution between mergers and quenching events suggests no physical connection to either fast or slow quenching. Hence, Simba predicts that major mergers induce starbursts, but are unrelated to quenching in either fast or slow mode.
dc.relation.ispartofMonthly Notices of the Royal Astronomical Societyen
dc.rights© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This work has been made available online in accordance with publisher policies or with permission. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the author created accepted manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at
dc.subjectGalaxies: evolutionen
dc.subjectGalaxies: formationen
dc.subjectQA75 Electronic computers. Computer scienceen
dc.subjectQB Astronomyen
dc.subjectQC Physicsen
dc.titleMergers, starbursts, and quenching in the Simba simulationen
dc.typeJournal articleen
dc.contributor.institutionUniversity of St Andrews. School of Physics and Astronomyen
dc.description.statusPeer revieweden

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