Overdensity of Lyman-break galaxy candidates around hot-dust-obscured galaxies

¹ Instituto de Estudios Astrofísicos, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Av. Ejército Libertador 441, Santiago, Chile
² Centre for Space Research, North-West University, Potchefstroom 2520, South Africa
³ ICRAR, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
⁴ Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile
⁵ Las Campanas Observatory, Carnegie Institution of Washington, Raúl Bitrán 1200, La Serena, Chile
⁶ Department of Physics, Northwestern College, 101 7th St SW, Orange City, IA 51041, USA
⁷ School of Physics, Korea Institute for Advanced Study, 85 Hoegiro, Dongdaemun-gu, Seoul 02455, Republic of Korea
⁸ National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Beijing 100101, China
⁹ Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University Beijing 102206, China
¹⁰ University of Chinese Academy of Sciences, Beijing 100049, China
¹¹ Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
¹² Department of Physics, University of Crete, 70013 Heraklion, Greece
¹³ Institute of Astrophysics, Foundation for Research and Technology–Hellas (FORTH), Heraklion GR-70013, Greece
¹⁴ School of Sciences, European University Cyprus, Diogenes street, Engomi, 1516 Nicosia, Cyprus
¹⁵ IPAC, California Institute of Technology, 1200 E. California Boulevard, Pasadena, 91125 CA, USA
¹⁶ Physics & Astronomy, University of Leicester, 1 University Road, Leicester LE1 7RH, UK

^⋆ Corresponding author; dejene.woldeyes@mail.udp.cl

Received: 6 July 2024
Accepted: 4 December 2024

Abstract

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.