Interacting galaxies in the IllustrisTNG simulations – III: (the rarity of) quenching in post-merger galaxies. Quai, S., Hani, M. H., Ellison, S. L., Patton, D. R., & Woo, J. arXiv e-prints, 2104:arXiv:2104.03327, April, 2021.
Interacting galaxies in the IllustrisTNG simulations – III: (the rarity of) quenching in post-merger galaxies [link]Paper  abstract   bibtex   
Galaxy mergers are traditionally one of the favoured mechanisms for quenching star formation. To test this paradigm in the context of modern cosmological simulations, we use the IllustrisTNG simulation to investigate the impact of individual merger events on quenching (i.e. star formation rate at least 3sig below the star-forming main sequence) within 500Myr after the coalescence phase.The rate of quenching amongst recently merged galaxies is compared with a control sample that is matched in redshift, stellar mass, star formation rate (SFR), black hole mass and environment.We find quenching to be uncommon among the descendants of post-merger galaxies, with only 5% of galaxies quenching within 500 Myr after the merger.Despite this low absolute rate, we find that quenching occurs in post-mergers at twice the rate of the control galaxies.The fraction of quenched post-merger descendants 1.5 Gyr after the merger becomes statistically indistinguishable from that of non-post-mergers, suggesting that mergers could speed up the quenching process in those post-mergers whose progenitors had physical conditions able to sustain effective active galactic nuclei (AGN) kinetic feedback, thus capable of removing gas from galaxies.Our results indicate that although quenching does not commonly occur promptly after coalescence, mergers nonetheless do promote the cessation of star formation in some post-mergers. We find that, in IllustrisTNG, it is the implementation of the AGN kinetic feedback that is responsible for quenching post-mergers, as well as non-post-merger controls.As a result of the released kinetic energy, galaxies experience gas loss and eventually, they will quench.Galaxies with an initially low gas fraction show a preferable pre-disposition towards quenching.The primary distinguishing factor between quenched and star-forming galaxies is gas fraction, with a sharp boundary at fgas=0.1 in TNG.
@article{quai_interacting_2021,
	title = {Interacting galaxies in the {IllustrisTNG} simulations -- {III}: (the rarity of) quenching in post-merger galaxies},
	volume = {2104},
	shorttitle = {Interacting galaxies in the {IllustrisTNG} simulations -- {III}},
	url = {http://adsabs.harvard.edu/abs/2021arXiv210403327Q},
	abstract = {Galaxy mergers are traditionally one of the favoured mechanisms for 
quenching star formation. To test this paradigm in the context of modern
cosmological simulations, we use the IllustrisTNG simulation to
investigate the impact of individual merger events on quenching (i.e.
star formation rate at least 3sig below the star-forming main sequence)
within 500Myr after the coalescence phase.The rate of quenching amongst
recently merged galaxies is compared with a control sample that is
matched in redshift, stellar mass, star formation rate (SFR), black hole
mass and environment.We find quenching to be uncommon among the
descendants of post-merger galaxies, with only 5\% of galaxies quenching
within 500 Myr after the merger.Despite this low absolute rate, we find
that quenching occurs in post-mergers at twice the rate of the control
galaxies.The fraction of quenched post-merger descendants 1.5 Gyr after
the merger becomes statistically indistinguishable from that of
non-post-mergers, suggesting that mergers could speed up the quenching
process in those post-mergers whose progenitors had physical conditions
able to sustain effective active galactic nuclei (AGN) kinetic feedback,
thus capable of removing gas from galaxies.Our results indicate that
although quenching does not commonly occur promptly after coalescence,
mergers nonetheless do promote the cessation of star formation in some
post-mergers. We find that, in IllustrisTNG, it is the implementation of
the AGN kinetic feedback that is responsible for quenching post-mergers,
as well as non-post-merger controls.As a result of the released kinetic
energy, galaxies experience gas loss and eventually, they will
quench.Galaxies with an initially low gas fraction show a preferable
pre-disposition towards quenching.The primary distinguishing factor
between quenched and star-forming galaxies is gas fraction, with a sharp
boundary at fgas=0.1 in TNG.},
	urldate = {2021-05-11},
	journal = {arXiv e-prints},
	author = {Quai, Salvatore and Hani, Maan H. and Ellison, Sara L. and Patton, David R. and Woo, Joanna},
	month = apr,
	year = {2021},
	keywords = {Astrophysics - Astrophysics of Galaxies},
	pages = {arXiv:2104.03327},
}

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