The MUSE Hubble Ultra Deep Field Survey. XI. Constraining the low-mass end of the stellar mass - star formation rate relation at z < 1
Abstract
Star-forming galaxies have been found to follow a relatively tight relation between stellar mass (M*) and star formation rate (SFR), dubbed the "star formation sequence". A turnover in the sequence has been observed, where galaxies with M* < 1010 M⊙ follow a steeper relation than their higher mass counterparts, suggesting that the low-mass slope is (nearly) linear. In this paper, we characterise the properties of the low-mass end of the star formation sequence between 7 ≤ log M*[M⊙] ≤ 10.5 at redshift 0.11 < z < 0.91. We use the deepest MUSE observations of the Hubble Ultra Deep Field and the Hubble Deep Field South to construct a sample of 179 star-forming galaxies with high signal-to-noise emission lines. Dust-corrected SFRs are determined from Hβ λ4861 and Hα λ6563. We model the star formation sequence with a Gaussian distribution around a hyperplane between logM*, logSFR, and log(1 + z), to simultaneously constrain the slope, redshift evolution, and intrinsic scatter. We find a sub-linear slope for the low-mass regime where log SFR [M⊙yr-1] = 0.83+0.07-0.06 log M*[M⊙]+1.74+0.66-0.68 log(1 + z), increasing with redshift. We recover an intrinsic scatter in the relation of σintr = 0.44+0.05-0.04, dex, larger than typically found at higher masses. As both hydrodynamical simulations and (semi-)analytical models typically favour a steeper slope in the low-mass regime, our results provide new constraints on the feedback processes which operate preferentially in low-mass halos.
Based on observations made with ESO telescopes at the La Silla Paranal Observatory under programme IDs ID 060.A-9100(C), 094.A-2089(B), 095.A-0010(A), 096.A-0045(A), and 096.A-0045(B).- Publication:
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Astronomy and Astrophysics
- Pub Date:
- November 2018
- DOI:
- 10.1051/0004-6361/201833136
- arXiv:
- arXiv:1808.04900
- Bibcode:
- 2018A&A...619A..27B
- Keywords:
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- galaxies: star formation;
- galaxies: formation;
- galaxies: evolution;
- galaxies: ISM;
- methods: statistical;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 20 pages and 12 figures. Accepted for publication in A&