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arXiv · 1708.08854

The BOSS Emission-Line Lens Survey V. Morphology and Substructure of Lensed Lyman-$\alpha$ Emitters at redshift $z\approx2.5$ in the BELLS GALLERY

Matthew Cornachione·Adam Bolton·Yiping Shu·Zheng Zheng·Antonio D. Montero-Dorta·Joel R. Brownstein·Masamune Oguri·Christopher S. Kochanek·Shude Mao·Ismael Perez-Fournon·Rui Marques-Chaves·Brice Menard
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Abstract

We present a morphological study of the 17 lensed Lyman-$\alpha$ emitter (LAE) galaxies of the Baryon Oscillation Spectroscopic Survey Emission-Line Lens Survey (BELLS) for the GALaxy-Ly$\alpha$ EmitteR sYstems (BELLS GALLERY) sample. This analysis combines the magnification effect of strong galaxy-galaxy lensing with the high resolution of the Hubble Space Telescope ($HST$) to achieve a physical resolution of $\sim$80 pc for this $2<z<3$ LAE sample, allowing a detailed characterization of the LAE rest-frame ultraviolet continuum surface brightness profiles and substructure. We use lens-model reconstructions of the LAEs to identify and model individual clumps, which we subsequently use to constrain the parameters of a generative statistical model of the LAE population. Since the BELLS GALLERY sample is selected primarily on the basis of Lyman-$\alpha$ emission, the LAEs that we study here are likely to be directly comparable to those selected in wide-field narrow-band LAE surveys, in contrast with the lensed LAEs identified in cluster lensing fields. We find an LAE clumpiness fraction of approximately 88%, significantly higher than found in previous (non-lensing) studies. We find a well-resolved characteristic clump half-light radii of $\sim$350 pc, a scale comparable to the largest H II regions seen in the local universe. This statistical characterization of LAE surface-brightness profiles will be incorporated into future lensing analyses using the BELLS GALLERY sample to constrain the incidence of dark-matter substructure in the foreground lensing galaxies.

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Matthew Cornachione, Adam Bolton, Yiping Shu, Zheng Zheng, Antonio D. Montero-Dorta, Joel R. Brownstein, Masamune Oguri, Christopher S. Kochanek, Shude Mao, Ismael Perez-Fournon, Rui Marques-Chaves, Brice Menard. 2017-08-29. The BOSS Emission-Line Lens Survey V. Morphology and Substructure of Lensed Lyman-$\alpha$ Emitters at redshift $z\approx2.5$ in the BELLS GALLERY. https://doi.org/10.3847/1538-4357/aaa412

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