Galaxy mergers can rapidly shut down star formation
Abstract
Galaxy mergers trigger both star formation and accretion onto the central supermassive black hole. As a result of subsequent energetic feedback processes, it has long been proposed that star formation may be promptly extinguished in galaxy merger remnants. However, this prediction of widespread, rapid quenching in late stage mergers has been recently called into question with modern simulations and has never been tested observationally. Here we perform the first empirical assessment of the long-predicted end phase in the merger sequence. Based on a sample of ~500 post-mergers identified from the Ultraviolet Near Infrared Optical Northern Survey (UNIONS), we show that the frequency of post-merger galaxies that have rapidly shutdown their star formation following a previous starburst is 30-60 times higher than expected from a control sample of non-merging galaxies. No such excess is found in a sample of close galaxy pairs, demonstrating that mergers can indeed lead to a rapid halt to star formation, but that this process only manifests after coalescence.
Citation
Ellison , S L , Wilkinson , S , Woo , J , Leung , H-H , Wild , V , Bickley , R W , Patton , D R , Quai , S & Gwyn , S 2022 , ' Galaxy mergers can rapidly shut down star formation ' , Monthly Notices of the Royal Astronomical Society , vol. Advance article , pp. L92-L96 . https://doi.org/10.1093/mnrasl/slac109
Publication
Monthly Notices of the Royal Astronomical Society
Status
Peer reviewed
ISSN
0035-8711Type
Journal article
Collections
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