VINTERGATAN IV : Cosmic phases of star formation in Milky Way-like galaxies
(2022) In Monthly Notices of the Royal Astronomical Society 516(2). p.2272-2279- Abstract
The star formation history of a galaxy is modulated by a plethora of internal processes and environmental conditions. The details of how these evolve and couple together are not fully understood yet. In this work, we study the effects that galaxy mergers and morphological transformations have on setting different modes of star formation at galactic scales and across cosmic time. We monitor the global properties of vintergatan, a 20 pc resolution cosmological zoom-in simulation of a Milky Way-Type galaxy. Between redshifts 1 and 5, we find that major mergers trigger multiple starburst episodes, corresponding to a tenfold drop of the gas depletion time down to 100 Myr. Bursty star formation is enabled by the emergence of a galactic disc,... (More)
The star formation history of a galaxy is modulated by a plethora of internal processes and environmental conditions. The details of how these evolve and couple together are not fully understood yet. In this work, we study the effects that galaxy mergers and morphological transformations have on setting different modes of star formation at galactic scales and across cosmic time. We monitor the global properties of vintergatan, a 20 pc resolution cosmological zoom-in simulation of a Milky Way-Type galaxy. Between redshifts 1 and 5, we find that major mergers trigger multiple starburst episodes, corresponding to a tenfold drop of the gas depletion time down to 100 Myr. Bursty star formation is enabled by the emergence of a galactic disc, when the rotational velocity of gas starts to dominate over its velocity dispersion. Coherent motions of gas then outweigh disordered ones, such that the galaxy responds to merger-induced forcings by redistributing large amounts of gas towards high densities. As a result, the overall star formation rate (SFR) is enhanced with an associated decrease in the depletion time. Before redshift 5, mergers were expected to be even more frequent. However, a more turbulent interstellar medium is incapable of reacting in such a collective manner so as to spark rapid star formation. Thus, a constant long depletion time of 1 Gyr is kept, along with a low, but gradually increasing SFR. After the last major merger at redshift 1, vintergatan spends the next 8 Gyr evolving secularly. It has a settled and adiabatically growing disc, and a constant SFR with gas depletion times of 1-2 Gyr. Our results are compatible with the observed rapid transition between different modes of star formation when galaxies leave the main sequence.
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- author
- Segovia Otero, Álvaro LU ; Renaud, Florent LU and Agertz, Oscar LU
- organization
- publishing date
- 2022-10-01
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- galaxies: interactions, galaxies: starburst, methods: numerical
- in
- Monthly Notices of the Royal Astronomical Society
- volume
- 516
- issue
- 2
- pages
- 8 pages
- publisher
- Oxford University Press
- external identifiers
-
- scopus:85139902955
- ISSN
- 0035-8711
- DOI
- 10.1093/mnras/stac2368
- language
- English
- LU publication?
- yes
- additional info
- Publisher Copyright: © 2022 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society.
- id
- b8b81dac-dc83-433c-9ec4-460fe19602c7
- date added to LUP
- 2026-07-02 15:49:03
- date last changed
- 2026-07-02 15:49:33
@article{b8b81dac-dc83-433c-9ec4-460fe19602c7,
abstract = {{<p>The star formation history of a galaxy is modulated by a plethora of internal processes and environmental conditions. The details of how these evolve and couple together are not fully understood yet. In this work, we study the effects that galaxy mergers and morphological transformations have on setting different modes of star formation at galactic scales and across cosmic time. We monitor the global properties of vintergatan, a 20 pc resolution cosmological zoom-in simulation of a Milky Way-Type galaxy. Between redshifts 1 and 5, we find that major mergers trigger multiple starburst episodes, corresponding to a tenfold drop of the gas depletion time down to 100 Myr. Bursty star formation is enabled by the emergence of a galactic disc, when the rotational velocity of gas starts to dominate over its velocity dispersion. Coherent motions of gas then outweigh disordered ones, such that the galaxy responds to merger-induced forcings by redistributing large amounts of gas towards high densities. As a result, the overall star formation rate (SFR) is enhanced with an associated decrease in the depletion time. Before redshift 5, mergers were expected to be even more frequent. However, a more turbulent interstellar medium is incapable of reacting in such a collective manner so as to spark rapid star formation. Thus, a constant long depletion time of 1 Gyr is kept, along with a low, but gradually increasing SFR. After the last major merger at redshift 1, vintergatan spends the next 8 Gyr evolving secularly. It has a settled and adiabatically growing disc, and a constant SFR with gas depletion times of 1-2 Gyr. Our results are compatible with the observed rapid transition between different modes of star formation when galaxies leave the main sequence.</p>}},
author = {{Segovia Otero, Álvaro and Renaud, Florent and Agertz, Oscar}},
issn = {{0035-8711}},
keywords = {{galaxies: interactions; galaxies: starburst; methods: numerical}},
language = {{eng}},
month = {{10}},
number = {{2}},
pages = {{2272--2279}},
publisher = {{Oxford University Press}},
series = {{Monthly Notices of the Royal Astronomical Society}},
title = {{VINTERGATAN IV : Cosmic phases of star formation in Milky Way-like galaxies}},
url = {{http://dx.doi.org/10.1093/mnras/stac2368}},
doi = {{10.1093/mnras/stac2368}},
volume = {{516}},
year = {{2022}},
}