The Astrophysical Journal, 988:229 (12pp), 2025 August 1
https://doi.org/10.3847/1538-4357/ade66f
Jaewon Yoo1, Jihye Shin2,3, Ho Seong Hwang4,5,6, Cristiano G. Sabiu7, Hyowon Kim8, Jongwan Ko2,3, and
Jong Chul Lee2aa
1 Quantum Universe Center, Korea Institute for Advanced Study, 85 Hoegi-ro, Dongdaemun-gu, Seoul 02455, Republic of Korea
2 Korea Astronomy and Space Science Institute (KASI), Daedeokdae-ro, Daejeon 34055, Republic of Korea; jhshin@kasi.re.kr
3 University of Science and Technology (UST), Gajeong-ro, Daejeon 34113, Republic of Korea
4 Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 08826, Republic of Korea
5 SNU Astronomy Research Center, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
6 Australian Astronomical Optics—Macquarie University, 105 Delhi Road, North Ryde, NSW 2113, Australia
7 Natural Science Research Institute (NSRI), University of Seoul, Seoul 02504, Republic of Korea
8 Departamento de Física, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso 2340000, Chile
Received 2025 May 1; revised 2025 June 14; accepted 2025 June 18; published 2025 July 28
Abstract
Recent studies have highlighted the potential of intracluster light (ICL) as a dark matter tracer. Moreover, ICL
coevolves with the brightest cluster galaxy (BCG) and the host cluster, making it a valuable tool for understanding cluster dynamics. In this study, we utilize 426 galaxy clusters (with total mass Mtot>1014M⊙ at z = 0) simulated in the cosmological hydrodynamical simulation Illustris TNG300 to compare the spatial distributions of dark matter, member galaxies, gas, and ICL and to assess their effectiveness as dark matter tracers in the central regions of clusters at Rvir <0.3. We apply the Weighted Overlap Coefficient, a methodology for quantifying the similarity of two-dimensional spatial distributions, to various components of the galaxy clusters at different dynamical stages. Our findings reveal that the spatial distributions of ICL combined with the BCG and gas closely resemble the dark matter distribution, with higher fidelity observed in more relaxed galaxy clusters with earlier half-mass epochs. These results demonstrate that the BCG+ICL component serves as an effective tracer of dark matter, consistent with previous observational studies linking cluster light to mass. Moreover, the degree of spatial similarity between the BCG+ICL and dark matter distributions appears to reflect the dynamical state of the cluster.
