Skip to main content

Research Repository

Advanced Search

Stellar splashback: the edge of the intracluster light

Deason, Alis J; Oman, Kyle A; Fattahi, Azadeh; Schaller, Matthieu; Jauzac, Mathilde; Zhang, Yuanyuan; Montes, Mireia; Bahé, Yannick M; Dalla Vecchia, Claudio; Kay, Scott T; Evans, Tilly A

Stellar splashback: the edge of the intracluster light Thumbnail


Profile Image

Dr Kyle Oman
Assistant Professor - Royal Society Dorothy Hodgkin Fellow

Matthieu Schaller

Yuanyuan Zhang

Mireia Montes

Yannick M Bahé

Claudio Dalla Vecchia

Scott T Kay


We examine the outskirts of galaxy clusters in the C-EAGLE simulations to quantify the ‘edges’ of the stellar and dark matter distribution. The radius of the steepest slope in the dark matter, commonly used as a proxy for the splashback radius, is located at ∼r200m⁠; the strength and location of this feature depends on the recent mass accretion rate, in good agreement with previous work. Interestingly, the stellar distribution (or intracluster light, ICL) also has a well-defined edge, which is directly related to the splashback radius of the halo. Thus, detecting the edge of the ICL can provide an independent measure of the physical boundary of the halo, and the recent mass accretion rate. We show that these caustics can also be seen in the projected density profiles, but care must be taken to account for the influence of substructures and other non-diffuse material, which can bias and/or weaken the signal of the steepest slope. This is particularly important for the stellar material, which has a higher fraction bound in subhaloes than the dark matter. Finally, we show that the ‘stellar splashback’ feature is located beyond current observational constraints on the ICL, but these large projected distances (≫1 Mpc) and low surface brightnesses (μ ≫ 32 mag arcsec−2) can be reached with upcoming observational facilities such as the Vera C. Rubin Observatory, the Nancy Grace Roman Space Telescope, and Euclid.


Deason, A. J., Oman, K. A., Fattahi, A., Schaller, M., Jauzac, M., Zhang, Y., …Evans, T. A. (2021). Stellar splashback: the edge of the intracluster light. Monthly Notices of the Royal Astronomical Society, 500(3), 4181-4192.

Journal Article Type Article
Acceptance Date Nov 13, 2020
Online Publication Date Nov 19, 2020
Publication Date 2021-01
Deposit Date Jun 29, 2021
Publicly Available Date Jun 29, 2021
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 500
Issue 3
Pages 4181-4192


Published Journal Article (2.3 Mb)

Copyright Statement
This article has been accepted for publication in Monthly Notices of the Royal astronomical Society ©: 2020 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

You might also like

Downloadable Citations