2025A&A...694A.121Z

Hot dust-obscured galaxies (hot DOGs) are a family of hyper-luminous, heavily obscured quasars. A number of studies based on the identification of companions at optical to far-infrared (FIR) wavelengths have shown that these objects reside in significantly overdense regions of the Universe. Here we present further characterisation of their environments by studying the surface density of Lyman break galaxy (LBG) candidates in the vicinity of three hot DOGs. For two of them, WISE J041010.60-091305.2 (W0410-0913) at z = 3.631 and WISE J083153.25+014010.8 (W0831+0140) at z = 3.912, we identify the candidate LBG companions using deep observations obtained with Baade/IMACS. For the third, WISE J224607.56-052634.9 (W2246-0526) at z = 4.601, we reanalyse previously published data obtained with Gemini-S/GMOS-S. We optimise the LBG photometric selection criteria at the redshift of each target using the COSMOS2020 catalog. When comparing the density of LBG candidates found in the vicinity of these hot DOGs with that in the COSMOS2020 catalog, we find overdensities of δ = 1.83 ± 0.08 (δ' = 7.49 ± 0.68), δ = 4.67 ± 0.21 (δ' = 29.17 ± 2.21), and δ = 2.36 ± 0.25 (δ' = 11.60 ± 1.96) around W0410-0913, W0831+0140, and W2246-0526, respectively, without (with) contamination correction. Additionally, we find that the overdensities are centrally concentrated around each hot DOG. Our analysis also reveals that the overdensity of the fields surrounding W0410-0913 and W0831+0140 declines steeply beyond physical scales of ∼2 Mpc. If these overdensities evolve into clusters by z = 0, the present results suggest that the hot DOG may correspond to the early formation stages of the brightest cluster galaxy. We were unable to determine whether or not this is also the case for W2246-0526 due to the smaller field of view (FOV) of the GMOS-S observations. Our results imply that hot DOGs may be excellent tracers of protoclusters.