Projection effects on pressure profiles: A case study of the Virgo replica

¹ Université Paris-Saclay, CNRS, Institut d’Astrophysique Spatiale, 91405 Orsay, France
² Université de Lille, CNRS, Centrale Lille, UMR 9189 CRIStAL, F-59000 Lille, France
³ Leibniz-Institut für Astrophysik (AIP), An der Sternwarte 16, 14482 Potsdam, Germany

^* e-mail: theo.lebeau@universite-paris-saclay.fr

Published online: 28 March 2024

Abstract

An accurate mass calibration of galaxy clusters is a crucial step towards precise constraints on the cosmological parameters σ₈ and Ω_m from clusters. Cluster masses can be estimated assuming hydrostatic equilibrium, but several physical and observational effects can alter this calculation. One of those are projection effects which are the focus of our present analysis. We present a case study of the simulated Virgo cluster, extracted from the CLONE constrained simulation. We study Virgo pressure and electron density quantities projected along different directions, including along the Milky Way-Virgo axis which mimics our observation direction. We show two main projection effects: the role of the integrated mass along the line of sight (LoS) in each chosen direction, including the presence of massive objects, and the signature of small scale physics in the core of the cluster along these directions.