Predicting Quiescence: The Dependence of Specific Star Formation Rate on Galaxy Size and Central Density at 0.5<z<2.5

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In this paper, we investigate the relationship between star formation and structure, using a mass-complete sample of 27,893 galaxies at $0.5<z<2.5$ selected from 3D-HST.

• We confirm that star-forming galaxies are larger than quiescent galaxies at fixed stellar mass (M$_{\star}$).
• However, in contrast with some simulations, there is only a weak relation between star formation rate (SFR) and size within the star-forming population: when dividing into quartiles based on residual offsets in SFR, we find that the sizes of star-forming galaxies in the lowest quartile are 0.27$\pm$0.06 dex smaller than the highest quartile.
• We show that 50% of star formation in galaxies at fixed M$_{\star}$ takes place within a narrow range of sizes (0.26 dex).