The MUSE Hubble Ultra Deep Field Survey. XI. Constraining the low-mass end of the stellar mass – star formation rate relation at z < 1 Article - Novembre 2018

Leindert Boogaard, Jarle Brinchmann, Nicolas Bouche, Mieke Paalvast, Roland Bacon, Rychard Bouwens, Thierry Contini, Madusha Gunawardhana, Hanae Inami, Raffaella Marino, Michael Maseda, Peter Mitchell, Themiya Nanayakkara, Johan Richard, Joop Schaye, Corentin Schreiber, Sandro Tacchella, Lutz Wisotzki, Johannes Zabl

Leindert Boogaard, Jarle Brinchmann, Nicolas Bouche, Mieke Paalvast, Roland Bacon, Rychard Bouwens, Thierry Contini, Madusha Gunawardhana, Hanae Inami, Raffaella Marino, Michael Maseda, Peter Mitchell, Themiya Nanayakkara, Johan Richard, Joop Schaye, Corentin Schreiber, Sandro Tacchella, Lutz Wisotzki, Johannes Zabl, « The MUSE Hubble Ultra Deep Field Survey. XI. Constraining the low-mass end of the stellar mass – star formation rate relation at z < 1  », Astronomy and Astrophysics - A&A, novembre 2018, A27. ISSN 0004-6361

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 * < 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.

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