On the UV compactness and morphologies of typical Lyman α emitters from z ∼ 2 to z ∼ 6

Paulino-Afonso, Ana and Sobral, David and Ribeiro, Bruno and Matthee, Jorryt and Da Graça Santos, Sergio and Calhau, Joao and Forshaw, Alex and Johnson, Andrea and Merrick, Joanna and Perez, Sara and Sheldon, Oliver (2018) On the UV compactness and morphologies of typical Lyman α emitters from z ∼ 2 to z ∼ 6. Monthly Notices of the Royal Astronomical Society, 476 (4). pp. 5479-5501. ISSN 0035-8711

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1709.04470v1 - Accepted Version
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Abstract

Lyman-a (Lya) is, intrinsically, the strongest nebular emission line in actively star-forming galaxies (SFGs), but its resonant nature and uncertain escape fraction limit its applicability. The structure, size, and morphology may be key to understand the escape of Lya photons and the nature of Lya emitters (LAEs). We investigate the rest-frame UV morphologies of a large sample of ~4000 LAEs from z~2 to z~6, selected in a uniform way with 16 different narrow- and medium-bands over the full COSMOS field (SC4K, Santos et al. in prep). From the magnitudes that we measure from UV stacks, we find that these galaxies are populating the faint end of the UV luminosity function. We find also that LAEs have roughly the same morphology from z~2 to z~6. The median size (re~1 kpc), ellipticities (slightly elongated with b/a~0.45), S\'ersic index (disk-like with n 5 to SFGs being a factor of ~2-4 larger than LAEs for z