2018A&A...619A..27B

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_*<10¹⁰M_☉ 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≤logM_*[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]=0.83^+0.07_–0.06 logM_*[M_☉]+1.74^+0.66_–0.68 log(1+z), increasing with redshift. We recover an intrinsic scatter in the relation of σ_intr=0.44^+0.05_–0.04dex, 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.