Variations in the slope of the resolved star-forming main sequence: A tool for constraining the mass of star-forming regions

Maan H. Hani*, Christopher C. Hayward, Matthew E. Orr, Sara L. Ellison, Paul Torrey, Norm Murray, Andrew Wetzel, Claude André Faucher-Giguère

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

The correlation between galaxies' integrated stellar masses and star formation rates (the 'star formation main sequence', SFMS) is a well-established scaling relation. Recently, surveys have found a relationship between the star formation rate (SFR) and stellar mass surface densities on kpc and sub-kpc scales (the 'resolved SFMS', rSFMS). In this work, we demonstrate that the rSFMS emerges naturally in Feedback In Realistic Environments 2 (FIRE-2) zoom-in simulations of Milky Way-mass galaxies. We make SFR and stellar mass maps of the simulated galaxies at a variety of spatial resolutions and star formation averaging time-scales and fit the rSFMS using multiple methods from the literature. While the absolute value of the SFMS slope (αMS) depends on the fitting method, the slope is steeper for longer star formation time-scales and lower spatial resolutions regardless of the fitting method employed. We present a toy model that quantitatively captures the dependence of the simulated galaxies' αMS on spatial resolution and use it to illustrate how this dependence can be used to constrain the characteristic mass of star-forming clumps.

Original languageEnglish (US)
Pages (from-to)L87-L91
JournalMonthly Notices of the Royal Astronomical Society: Letters
Volume493
Issue number1
DOIs
StatePublished - Jan 28 2020

Keywords

  • galaxies: evolution
  • galaxies: fundamental parameters
  • galaxies: star formation

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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