1. The Compact UV Size of Green Pea Galaxies As Local Analogs of High-redshift Ly$��$-Emitters
- Author
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Kim, Keunho J., Malhotra, Sangeeta, Rhoads, James E., and Yang, Huan
- Subjects
Astrophysics of Galaxies (astro-ph.GA) ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
We study the dependence of Ly$��$ escape from galaxies on UV continuum size and luminosity using a sample of 40 Green Pea (GP) galaxies, which are the best local analogs of high-redshift Ly$��$-emitters (LAEs). We use the Cosmic Origins Spectrograph near-ultraviolet images from the \textit{Hubble Space Telescope} to measure the UV size and luminosity with $0.047''$ spatial resolution. Like most galaxies the GPs show a log-normal size distribution. They also show a positive correlation between size and UV-continuum luminosity. The slope of the size-continuum luminosity relation for GPs is consistent with those of continuum-selected star-forming galaxies at low and high redshifts. A distinctive feature of GPs is a very compact typical radius of 0.33 kpc with a population spread (1$��$) of 0.19 kpc. The peak of the size distribution and the intercept of the size-luminosity relation of GPs are noticeably smaller than those of continuum-selected star-forming galaxies at similar redshifts. There are statistically significant anti-correlations found between the circularized half-light radius ($r_{\rm cir,50}$), the Ly$��$ equivalent width (EW(Ly$��$)), and the Ly$��$ escape faction ($f^{Ly��}_{esc}$), suggesting that small UV-continuum radii are crucial for Ly$��$ emission. GPs and high-redshift LAEs have similar sizes, once spatial resolution effects are properly considered. Our results show that a compact/small size is crucial for escape of Ly$��$ photons, and that Ly$��$-emitters show constant characteristic size independent of their redshift., 10 pages, 4 figures, 2 tables, accepted by ApJ; doi:10.3847/1538-4357/abf833
- Published
- 2021
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