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Spatially resolved star formation and fuelling in galaxy interactions

Moreno, Jorge and Torrey, Paul and Ellison, Sara L. and Patton, David R and Bottrell, Connor and Bluck, Asa F. L. and Hani, Maan H. and Hayward, Christopher C. and Bullock, James S. and Hopkins, Philip F. and Hernquist, Lars (2021) Spatially resolved star formation and fuelling in galaxy interactions. Monthly Notices of the Royal Astronomical Society, 503 (3). pp. 3113-3133. ISSN 0035-8711.

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We investigate the spatial structure and evolution of star formation and the interstellar medium (ISM) in interacting galaxies. We use an extensive suite of parsec-scale galaxy-merger simulations (stellar mass ratio = 2.5:1), which employs the ‘Feedback In Realistic Environments-2’ model (FIRE-2). This framework resolves star formation, feedback processes, and the multiphase structure of the ISM. We focus on the galaxy-pair stages of interaction. We find that close encounters substantially augment cool (H I) and cold-dense (H₂) gas budgets, elevating the formation of new stars as a result. This enhancement is centrally concentrated for the secondary galaxy, and more radially extended for the primary. This behaviour is weakly dependent on orbital geometry. We also find that galaxies with elevated global star formation rate (SFR) experience intense nuclear SFR enhancement, driven by high levels of either star formation efficiency (SFE) or available cold-dense gas fuel. Galaxies with suppressed global SFR also contain a nuclear cold-dense gas reservoir, but low SFE levels diminish SFR in the central region. Concretely, in the majority of cases, SFR enhancement in the central kiloparsec is fuel-driven (55 per cent for the secondary, 71 per cent for the primary) – while central SFR suppression is efficiency-driven (91 per cent for the secondary, 97 per cent for the primary). Our numerical predictions underscore the need of substantially larger, and/or merger-dedicated, spatially resolved galaxy surveys – capable of examining vast and diverse samples of interacting systems – coupled with multiwavelength campaigns aimed to capture their internal ISM structure.

Item Type:Article
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URLURL TypeDescription Paper ItemVideos
Moreno, Jorge0000-0002-3430-3232
Torrey, Paul0000-0002-5653-0786
Ellison, Sara L.0000-0002-1768-1899
Patton, David R0000-0002-1871-4154
Bottrell, Connor0000-0003-4758-4501
Bluck, Asa F. L.0000-0001-6395-4504
Hani, Maan H.0000-0002-5351-2291
Hayward, Christopher C.0000-0003-4073-3236
Bullock, James S.0000-0003-4298-5082
Hopkins, Philip F.0000-0003-3729-1684
Hernquist, Lars0000-0001-6950-1629
Additional Information:© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model ( Accepted 2020 September 22. Received 2020 September 22; in original form 2020 July 24. We thank the anonymous reviewer for their thorough and insightful comments, which were shared with us on a heroically reasonable time-scale in the middle of the Covid-19 pandemic. Their suggestions certainly improved the quality of this manuscript. The computations in this paper were run on the Odyssey cluster supported by the FAS Division of Science, Research Computing Group at Harvard University. Support for JM is provided by the National Science Foundation (NSF, Award Number 1516374), and by the Harvard Institute for Theory and Computation, through their Visiting Scholars Program. DRP and SLE gratefully acknowledge NSERC for Discovery Grants which helped to fund this research. CB acknowledges the support of a National Sciences and Engineering Research Council of Canada (NSERC) Graduate Scholarship. AB acknowledges European Research Council (ERC) Advanced Grant 695671 ‘Quench’ and support from the STFC. MHH acknowledges the receipt of a Vanier Canada Graduate Scholarship. The Flatiron Institute is supported by the Simons Foundation. Support for PFH is provided by NSF Collaborative Research Grants 1715847 and 1911233, NSF CAREER grant 1455342, National Aeronautics Space Agency (NASA) grants 80NSSC18K0562, Jet Propulsion Laboratory (JPL) 1589742. We honour the invaluable labour of the maintenance and clerical staff at our institutions – whose contributions make our scientific discoveries a reality – and urge institutions everywhere to protect these essential workers from the worldwide economic contraction caused by the pandemic. This research was conducted on Tongva-Gabrielino Indigenous land. DATA AVAILABILITY. The data underlying this article will be shared on reasonable request to the corresponding author.
Group:Astronomy Department
Funding AgencyGrant Number
Harvard Institute for Theory and ComputationUNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
European Research Council (ERC)695671
Science and Technology Facilities Council (STFC)UNSPECIFIED
Simons FoundationUNSPECIFIED
Subject Keywords:methods: numerical, ISM: structure, galaxies: evolution, galaxies: interactions, galaxies: starburst, galaxies: star formation
Issue or Number:3
Record Number:CaltechAUTHORS:20210621-223906560
Persistent URL:
Official Citation:Jorge Moreno, Paul Torrey, Sara L Ellison, David R Patton, Connor Bottrell, Asa F L Bluck, Maan H Hani, Christopher C Hayward, James S Bullock, Philip F Hopkins, Lars Hernquist, Spatially resolved star formation and fuelling in galaxy interactions, Monthly Notices of the Royal Astronomical Society, Volume 503, Issue 3, May 2021, Pages 3113–3133,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:109520
Deposited By: George Porter
Deposited On:22 Jun 2021 15:42
Last Modified:22 Jun 2021 15:42

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