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arXiv · 1612.05262

The Size Evolution of Star-forming Galaxies Since z~7 Using ZFOURGE

Rebecca J. Allen·Glenn G. Kacprzak·Karl Glazebrook·Ivo Labbe·Kim-Vy H. Tran·Lee R. Spitler·Michael Cowley·Themiya Nanayakkara·Casey Papovich·Ryan Quadri·Caroline M. S. Straatman·Vithal Tilvi·Pieter van Dokkum
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Abstract

For the first time, we present the size evolution of a mass-complete (log(M*/Msol)>10) sample of star-forming galaxies over redshifts z=1-7, selected from the FourStar Galaxy Evolution Survey (ZFOURGE). Observed H-band sizes are measured from the Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (CANDELS) Hubble Space Telescope (HST)/F160W imaging. Distributions of individual galaxy masses and sizes illustrate that a clear mass-size relation exists up to z~7. At z~7, we find that the average galaxy size from the mass-size relation is more compact at a fixed mass of log(M*/Msol)=10.1, with r_1/2,maj=1.02+/-0.29 kpc, than at lower redshifts. This is consistent with our results from stacking the same CANDELS HST/F160W imaging, when we correct for galaxy position angle alignment. We find that the size evolution of star-forming galaxies is well fit by a power law of the form r_e = 7.07(1 + z)^-0.89 kpc, which is consistent with previous works for normal star-formers at 1 4 (r_e\propto(1 +z)^-1.2+/-0.06). Therefore, we conclude the Lyman break galaxies likely represent a subset of highly star-forming galaxies that exhibit rapid size growth at z>4.

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Rebecca J. Allen, Glenn G. Kacprzak, Karl Glazebrook, Ivo Labbe, Kim-Vy H. Tran, Lee R. Spitler, Michael Cowley, Themiya Nanayakkara, Casey Papovich, Ryan Quadri, Caroline M. S. Straatman, Vithal Tilvi, Pieter van Dokkum. 2016-12-15. The Size Evolution of Star-forming Galaxies Since z~7 Using ZFOURGE. https://doi.org/10.3847/2041-8213%2F834%2F2%2Fl11

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