---
_id: '11540'
abstract:
- lang: eng
  text: Observations have revealed that the star formation rate (SFR) and stellar
    mass (Mstar) of star-forming galaxies follow a tight relation known as the galaxy
    main sequence. However, what physical information is encoded in this relation
    is under debate. Here, we use the EAGLE cosmological hydrodynamical simulation
    to study the mass dependence, evolution, and origin of scatter in the SFR–Mstar
    relation. At z = 0, we find that the scatter decreases slightly with stellar mass
    from 0.35 dex at Mstar ≈ 109 M⊙ to 0.30 dex at Mstar ≳ 1010.5 M⊙. The scatter
    decreases from z = 0 to z = 5 by 0.05 dex at Mstar ≳ 1010 M⊙ and by 0.15 dex for
    lower masses. We show that the scatter at z = 0.1 originates from a combination
    of fluctuations on short time-scales (ranging from 0.2–2 Gyr) that are presumably
    associated with self-regulation from cooling, star formation, and outflows, but
    is dominated by long time-scale (∼10 Gyr) variations related to differences in
    halo formation times. Shorter time-scale fluctuations are relatively more important
    for lower mass galaxies. At high masses, differences in black hole formation efficiency
    cause additional scatter, but also diminish the scatter caused by different halo
    formation times. While individual galaxies cross the main sequence multiple times
    during their evolution, they fluctuate around tracks associated with their halo
    properties, i.e. galaxies above/below the main sequence at z = 0.1 tend to have
    been above/below the main sequence for ≫1 Gyr.
acknowledgement: JM acknowledges the support of a Huygens PhD fellowship from Leiden
  University. We thank Camila Correa for help analysing snipshot merger trees. We
  thank the anonymous referee for constructive comments. We also thank Jarle Brinchmann,
  Rob Crain, Antonios Katsianis, Paola Popesso, and David Sobral for discussions and
  suggestions. We also thank the participants of the Lorentz Center workshop ‘A Decade
  of the Star-Forming Main Sequence’ held on 2017 September 4–8, for discussions and
  ideas. We have benefited from the public available programming language PYTHON,
  including the NUMPY, MATPLOTLIB, and SCIPY (Hunter 2007) packages and the TOPCAT
  analysis tool (Taylor 2013).
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Jorryt J
  full_name: Matthee, Jorryt J
  id: 7439a258-f3c0-11ec-9501-9df22fe06720
  last_name: Matthee
  orcid: 0000-0003-2871-127X
- first_name: Joop
  full_name: Schaye, Joop
  last_name: Schaye
citation:
  ama: Matthee JJ, Schaye J. The origin of scatter in the star formation rate–stellar
    mass relation. <i>Monthly Notices of the Royal Astronomical Society</i>. 2019;484(1):915-932.
    doi:<a href="https://doi.org/10.1093/mnras/stz030">10.1093/mnras/stz030</a>
  apa: Matthee, J. J., &#38; Schaye, J. (2019). The origin of scatter in the star
    formation rate–stellar mass relation. <i>Monthly Notices of the Royal Astronomical
    Society</i>. Oxford University Press. <a href="https://doi.org/10.1093/mnras/stz030">https://doi.org/10.1093/mnras/stz030</a>
  chicago: Matthee, Jorryt J, and Joop Schaye. “The Origin of Scatter in the Star
    Formation Rate–Stellar Mass Relation.” <i>Monthly Notices of the Royal Astronomical
    Society</i>. Oxford University Press, 2019. <a href="https://doi.org/10.1093/mnras/stz030">https://doi.org/10.1093/mnras/stz030</a>.
  ieee: J. J. Matthee and J. Schaye, “The origin of scatter in the star formation
    rate–stellar mass relation,” <i>Monthly Notices of the Royal Astronomical Society</i>,
    vol. 484, no. 1. Oxford University Press, pp. 915–932, 2019.
  ista: Matthee JJ, Schaye J. 2019. The origin of scatter in the star formation rate–stellar
    mass relation. Monthly Notices of the Royal Astronomical Society. 484(1), 915–932.
  mla: Matthee, Jorryt J., and Joop Schaye. “The Origin of Scatter in the Star Formation
    Rate–Stellar Mass Relation.” <i>Monthly Notices of the Royal Astronomical Society</i>,
    vol. 484, no. 1, Oxford University Press, 2019, pp. 915–32, doi:<a href="https://doi.org/10.1093/mnras/stz030">10.1093/mnras/stz030</a>.
  short: J.J. Matthee, J. Schaye, Monthly Notices of the Royal Astronomical Society
    484 (2019) 915–932.
date_created: 2022-07-08T07:48:31Z
date_published: 2019-03-01T00:00:00Z
date_updated: 2022-08-19T06:42:43Z
day: '01'
doi: 10.1093/mnras/stz030
extern: '1'
external_id:
  arxiv:
  - '1805.05956'
intvolume: '       484'
issue: '1'
keyword:
- Space and Planetary Science
- 'Astronomy and Astrophysics : galaxies: evolution'
- 'galaxies: formation'
- 'galaxies: star formation'
- 'cosmology: theory'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/1805.05956
month: '03'
oa: 1
oa_version: Preprint
page: 915-932
publication: Monthly Notices of the Royal Astronomical Society
publication_identifier:
  eissn:
  - 1365-2966
  issn:
  - 0035-8711
publication_status: published
publisher: Oxford University Press
quality_controlled: '1'
scopus_import: '1'
status: public
title: The origin of scatter in the star formation rate–stellar mass relation
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 484
year: '2019'
...