Ly$\alpha$ imaging around the hyperluminous dust-obscured quasar W2246$-$0526 at $z=4.6$

TL;DR

This study uses VLT imaging to detect an overdensity of Ly$ ext{alpha}$ emitters around the most distant Hot DOG galaxy at z=4.6, providing evidence of its dense environment and supporting merger-driven growth theories.

Contribution

First direct evidence of an overdense environment around a high-redshift Hot DOG using Ly$ ext{alpha}$ imaging, linking environment to galaxy evolution.

Findings

Overdensity of Ly$ ext{alpha}$} emitters detected around W2246$-$0526

Supports merger-driven growth model for Hot DOGs

Hot DOG resides in a dense, Mpc-scale environment

Abstract

Hot dust-obscured galaxies (Hot DOGs) are a population of hyperluminous, heavily obscured quasars discovered by the \emph{Wide-field Infrared Survey Explorer} (\emph{WISE}) all-sky survey at high redshift. Observations suggested the growth of these galaxies may be driven by mergers. Previous environmental studies have statistically shown Hot DOGs may reside in dense regions. Here we use the Very Large Telescope (VLT) narrowband and broadband imaging to search for Ly$\alpha$ emitters (LAEs) in the 6.8' * 6.8' field of the Hot DOG W2246$-$0526 at $z=4.6$. W2246$-$0526 is the most distant Hot DOG. We find that there is an overdensity of LAEs in W2246$-$0526 field compared with the blank fields. This is the direct evidence that this most distant Hot DOG is in an overdense environment on the Mpc scale, and the result relates to the merger origin of Hot DOGs.