The MUSE Hubble Ultra Deep Field Survey. XI. Constraining the low-mass end of the stellar mass – star formation raterelation at z < 1

International audienceStar-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 * < 10 10 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 log M * , log SFR, 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 σ intr = 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