Sizes of Lensed Lower-luminosity z=4-8 Galaxies from the Hubble Frontier Field Program

Abstract

We constrain the rest-UV size-luminosity relation for star-forming galaxies at z~4 and z~6, 7, and 8 identified behind clusters from the Hubble Frontier Fields (HFF) program. The size-luminosity relation is key to deriving accurate luminosity functions (LF) for faint galaxies. Making use of the latest lensing models and full data set for these clusters, lensing-corrected sizes and luminosities are derived for 68 z~4, 184 z~6, 93 z~7, and 53 z~8 galaxies. We show that size measurements can be reliably measured up to linear magnifications of 30x, where the lensing models are well calibrated. The sizes we measure span a >1-dex range, from <50 pc to >~500 pc. Uncertainties are based on both the formal fit errors and systematic differences between the public lensing models. These uncertainties range from ~20 pc for the smallest sources to 50 pc for the largest. Using a forward-modeling procedure to model the impact of incompleteness and magnification uncertainties, we characterize the size-luminosity relation at both z~4 and z~6-8. We find that the source sizes of star-forming galaxies at z~4 and z~6-8 scale with luminosity L as L^{0.54\pm0.08} and L^{0.40+/-0.04}, respectively, such that lower luminosity (>~-18 mag) galaxies are smaller than expected from extrapolating the size-luminosity relation at high luminosities (<~-18 mag). The new evidence for a steeper size-luminosity relation (3 sigma) adds to earlier evidence for small sizes based on the prevalence of highly magnified galaxies in high shear regions, theoretical arguments against upturns in the LFs, and other independent determinations of the size-luminosity relation from the HFF clusters.

22 pages, 18 figures, 2 tables, accepted for publication into ApJ. arXiv admin note: substantial text overlap with arXiv:1711.02090

References in corpus (27)

• EAZY: A Fast, Public Photometric Redshift Code
• 3D-HST+CANDELS: The Evolution of the Galaxy Size-Mass Distribution since $z=3$
• UV Luminosity Functions at redshifts z~4 to z~10: 10000 Galaxies from HST Legacy Fields
• The Hubble Ultra Deep Field
• Hubble Space Telescope Combined Strong and Weak Lensing Analysis of the CLASH Sample: Mass and Magnification Models and Systematic Uncertainties
• Mass and magnification maps for the Hubble Space Telescope Frontier Fields clusters: implications for high redshift studies
• Multi-scale cluster lens mass mapping I. Strong Lensing modelling
• Lens models and magnification maps of the six Hubble Frontier Fields clusters
• Paving the way for the JWST: witnessing globular cluster formation at z>3
• Hubble Frontier Fields First Complete Cluster Data: Faint Galaxies at $z\sim 5-10$ for UV Luminosity Functions and Cosmic Reionization
• Essential physics of early galaxy formation
• HST morphologies of local Lyman break galaxy analogs I: Evidence for starbursts triggered by merging
• Frontier Fields: High-Redshift Predictions and Early Results
• The Luminosity Function at z~8 from 97 Y-band dropouts: Inferences About Reionization
• The sizes of $z\sim 6-8$ lensed galaxies from the Hubble Frontier Fields Abell 2744 data
• Star Formation at z=2.481 in the Lensed Galaxy SDSS J1110+6459: Star Formation down to 30 parsec scales
• Hubble Frontier Fields: The Geometry and Dynamics of the Massive Galaxy Cluster Merger MACSJ0416.1-2403
• Half-mass radii of quiescent and star-forming galaxies evolve slowly from 0 < z < 2.5: implications for galaxy assembly histories
• Free Form Lensing Implications for the Collision of Dark Matter and Gas in the Frontier Fields Cluster MACSJ0416.1-2403
• The Very Faint End of the UV Luminosity Function over Cosmic Time: Constraints from the Local Group Fossil Record
• A Rigorous Free-form Lens Model of Abell 2744 to Meet the Hubble Frontier Fields Challenge
• The Reionization of Carbon
• Near-Field Limits on the Role of Faint Galaxies in Cosmic Reionization
• Unbiased Differential Size Evolution and the Inside-Out Growth of Galaxies in the Deep CANDELS GOODS Fields at $1\le z\le 7$
• Dark-ages reionization and galaxy formation simulation--VII. The sizes of high-redshift galaxies
• Search Instructions for Globular Clusters in Formation at High Redshifts
• Simulating Deep Hubble Images With Semi-empirical Models of Galaxy Formation

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