Splashback in galaxy clusters as a probe of cosmic expansion and gravity

Susmita Adhikari, Jeremy Sakstein, Bhuvnesh Jain, Neal Dalal, Baojiu Li

Research output: Contribution to journalArticlepeer-review


The splashback radius is a physical scale in dark matter halos that is set by the gravitational dynamics of recently accreted shells. We use analytical models and N-body simulations to study the dependence of splashback on dark energy and screened modified gravity theories. In modified gravity models, the transition from screened to unscreened regions typically occurs in the cluster outskirts, suggesting potentially observable signatures in the splashback feature. We investigate the location of splashback in both chameleon and Vainshtein screened models and find significant differences compared with ΛCDM predictions. We also find an interesting interplay between dynamical friction and modified gravity, providing a distinctive signature for modified gravity models in the behavior of the splashback feature as a function of galaxy luminosity.

Original languageEnglish (US)
Article number033
JournalJournal of Cosmology and Astroparticle Physics
Issue number11
StatePublished - Nov 20 2018


  • dark matter simulations
  • dark matter theory
  • galaxy clusters
  • galaxy dynamics

ASJC Scopus subject areas

  • Astronomy and Astrophysics


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