Generalised scalar-tensor theories of gravity and pressure profiles of galaxy clusters

¹ SISSA-International School for Advanced Studies, Via Bonomea 265, 34136 Trieste, Italy
² INFN, Sezione di Trieste, Via Valerio 2, I-34127 Trieste, Italy
³ IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy
⁴ Dipartimento di Fisica, Sapienza Universitá di Roma, P.le Aldo Moro 2, 00185, Roma, Italy
⁵ INAF - Osservatorio Astronomico di Roma, Via Frascati 33, 00040, Monteporzio Catone, Roma, Italy
⁶ INFN- Sezione di Roma 1, P.le Aldo Moro 2, 00185, Roma, Italy

^* e-mail: sandeep.haridasu@sissa.it

Published online: 17 January 2022

Abstract

In the current proceedings, we summarise the results presented during the mm Universe@NIKA2 conference, taken from our main results in [1]. We test the Degenerate higher-order scalar-tensor(DHOST) theory as a generalised platform for scalar-tensor theory at galaxy cluster scales to predict in such static systems small scale modification to the gravitational potential. DHOST theory is not only a good alternative to ΛCDM for the background evolution but also predicts small-scale modification to the gravitational potential in static systems such as galaxy clusters. With a sample of 12 clusters with accurate Xray Intra Cluster Medium (ICM) data (X-COP project) and Sunyaev-Zel’dovich (SZ) ICM pressure (Planck satellite), we place preliminary constraints on the DHOST parameter (Ξ1) defining the deviation from GR. Moreover, we also collect a few supplementary analyses we have performed during the course: i) Gaussian process reconstruction without parametric assumptions, ii) P_SZ-only data analysis not aided by the X-ray data. Finally, we present possible extensions to the current work which may benefit from future high sensitivity and spatial resolution observations.