RELICS: Small Lensed $z\ge 5.5$ Galaxies Selected as Potential Lyman Continuum Leakers

Abstract

We present size measurements of 78 high-redshift ($z\ge 5.5$) galaxy candidates from the Reionisation Lensing Cluster Survey (RELICS). These distant galaxies are well-resolved due to the gravitational lensing power of foreground galaxy clusters, imaged by the Hubble Space Telescope (HST) and the Spitzer Space Telescope. We compute sizes using the forward-modeling code Lenstruction and account for magnification using public lens models. The resulting size-magnitude measurements confirm the existence of many small galaxies with effective radii $R_{\mathrm{eff}}<200$ pc in the early universe, in agreement with previous studies. In addition, we highlight compact and highly star-forming sources with star formation rate surface densities ${\Sigma }_{\text{SFR}}>10M_{\odot }{\text{yr}}^{-1}{\text{kpc}}^{-2}$ as possible Lyman continuum leaking candidates that could be major contributors to the process of reionisation. Future spectroscopic follow-up of these compact galaxies (e.g., with the James Webb Space Telescope) will further clarify their role in reionisation and the physics of early star formation.

10 pages, 5 figures

References in corpus (26)

• EAZY: A Fast, Public Photometric Redshift Code
• 3D-HST+CANDELS: The Evolution of the Galaxy Size-Mass Distribution since $z=3$
• Structure and star formation in galaxies out to z=3: evidence for surface density dependent evolution and upsizing
• Conditions for Reionizing the Universe with A Low Galaxy Ionizing Photon Escape Fraction
• Using Lyman-alpha to detect galaxies that leak Lyman continuum
• New observations of z~7 galaxies: evidence for a patchy reionization
• Lyman-alpha spectral properties of five newly discovered Lyman continuum emitters
• Multi-scale cluster lens mass mapping I. Strong Lensing modelling
• The Low-Redshift Lyman Continuum Survey I: New, Diverse Local Lyman-Continuum Emitters
• High-precision Photometric Redshifts from Spitzer/IRAC: Extreme [3.6]-[4.5] Colors Identify Galaxies in the Redshift Range z~6.6-6.9
• Q1549-C25: A Clean Source of Lyman-Continuum Emission at $z=3.15$
• Lyman continuum leakage from low-mass galaxies with Mstar < 1.E8 Msun
• A Geometrically Supported $z\sim 10$ Candidate Multiply-Imaged by the Hubble Frontier Fields Cluster Abell 2744
• The sizes of $z\sim 6-8$ lensed galaxies from the Hubble Frontier Fields Abell 2744 data
• Relations Between the Sizes of Galaxies and their Dark Matter Halos at Redshifts $0<z<3$
• Do galaxies that leak ionizing photons have extreme outflows?
• (Re)Solving Reionization with Lyα: How Bright Lyα Emitters account for the $z\approx 2-8$ Cosmic Ionizing Background
• No strong dependence of Lyman continuum leakage on physical properties of star-forming galaxies at $3.1\lesssim \mathbf{z}\lesssim 3.5$
• Sizes of Lensed Lower-luminosity z=4-8 Galaxies from the Hubble Frontier Field Program
• Shapes and alignments of dark matter haloes and their brightest cluster galaxies in 39 strong lensing clusters
• The evolution of the size-mass relation at $z$=1-3 derived from the complete Hubble Frontier Fields data set
• Constraining Lyman-alpha spatial offsets at $3<z<5.5$ from VANDELS slit spectroscopy
• Structures of Local Galaxies Compared to High Redshift Star-forming Galaxies
• The Compact UV Size of Green Pea Galaxies As Local Analogs of High-redshift Ly$\alpha$-Emitters
• The size-luminosity relation of lensed galaxies at $z=6-9$ in the Hubble Frontier Fields
• RELICS-DP7: Spectroscopic Confirmation of a Dichromatic Primeval Galaxy at z ~ 7

Cited by in corpus (2)

• RELICS: Small-scale Star Formation in Lensed Galaxies at $z=6-10$
• Anatomy of a z=6 Lyman-α emitter down to parsec scales: extreme UV slopes, metal-poor regions and possibly leaking star clusters