Unbiased Differential Size Evolution and the Inside-Out Growth of Galaxies in the Deep CANDELS GOODS Fields at $1\le z\le 7$

Abstract

We present a size analysis of a sample of $\sim$ 49,000 galaxies from the CANDELS GOODS North and South fields using redshift-independent relative surface brightness metrics to determine an unbiased measure of the differential size evolution of galaxies at $1\le z\le 7$. We introduce a novel method of removing foreground objects from distant galaxy ($z>3$) images that makes use of the Lyman-break at 912Å, in what we call `2-D Lyman-Break Imaging'. The images used are in the rest-frame optical at $z<3$ and progressively bluer bands at $z>3$. They are therefore subject to K-correction and cosmological dimming effects which are tested and corrected for. We separately consider a mass-selected sample (with masses in the range 10${}^9$M${}_{\odot }$$\le$M${}_{\ast }$$\le$10${}^{10.5}$M${}_{\odot }$) and a number density selected sample (using a constant number density of $n=1\times 10^{-4}$Mpc${}^{-3}$). Instead of utilising the commonly used, but potentially biased, effective radii for size measurements, we measure the redshift-independent Petrosian radius, defined by the parameter $\eta$, for each galaxy for three values of $\eta$ and use this as a proxy for size. The evolution of the measured radii can be described by a power-law of the form $R_{Petr}=\alpha (1+z{)}^{\beta }$kpc where $\beta <0$. We find that the outer radius increases more rapidly, suggesting that as a galaxy grows mass is added to its outer regions via an inside-out growth. This growth is stronger for the number density selected sample, with a growth rate of nearly three in the outer radii compared to the inner. We test and confirm these results using a series of image simulations.

16 pages, 11 figures

References in corpus (13)

• EAZY: A Fast, Public Photometric Redshift Code
• 3D-HST+CANDELS: The Evolution of the Galaxy Size-Mass Distribution since $z=3$
• Size evolution of the most massive galaxies at 1.7<z<3 from GOODS NICMOS survey imaging
• Galaxy Merger Morphologies and Time-Scales from Simulations of Equal-Mass Gas-Rich Disc Mergers
• The Relation Between SFR and Stellar Mass for Galaxies at 3.5 $\le z\le$ 6.5 in CANDELS
• The mass evolution of the first galaxies: stellar mass functions and star formation rates at $4<z<7$ in the CANDELS GOODS-South field
• The dramatic size evolution of elliptical galaxies and the quasar feedback
• Observational constraints on the merger history of galaxies since $z\approx 6$: Probabilistic galaxy pair counts in the CANDELS fields
• The Physical Nature of Rest-UV Galaxy Morphology During the Peak Epoch of Galaxy Formation
• The Size Evolution of Star-forming Galaxies Since z~7 Using ZFOURGE
• The Formation of Bulges, Discs and Two Component Galaxies in the CANDELS Survey at z < 3
• A New View of the Size-Mass Distribution of Galaxies: Using $r_{20}$ and $r_{80}$ instead of $r_{50}$
• Tracing galaxy populations through cosmic time: A critical test of methods for connecting the same galaxies between different redshifts at $z<3$

Cited by in corpus (7)

• The ALPINE-ALMA [CII] survey: The contribution of major mergers to the galaxy mass assembly at z~5
• Galaxy Sizes Since $z=2$ from the Perspective of Stellar Mass Distribution within Galaxies
• Observations of the Initial Formation and Evolution of Spiral galaxies at $1<z<3$ in the CANDELS fields
• SDSS-IV MaNGA: Excavating the fossil record of stellar populations in spiral galaxies
• The evolution of compact massive quiescent and starforming galaxies derived from the $R_e-R_h$ and $M_{\mathrm{star}}-M_h$ relations
• The differences between mass- and light-derived structural parameters over time for MaNGA Elliptical galaxies
• Damped Lyman-$\alpha$ absorbers and atomic hydrogen in galaxies: the view of the GAEA model