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) PSZ-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.
Highlights
Einstein developed the standard general relativity (GR) by considering gravity as warps and curves in the fabric of geometric space-time, and that geometry of space-time is described only by a metric
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
If we plan to keep the basic metric structure because of the large success of GR, and add one scalar degrees of freedom to explain the acceleration, the degenerate higher-order scalar-tensor (DHOST) theory is the best possible platform to test the largest classes of scalar-tensor theories [2, 3]
Summary
Einstein developed the standard general relativity (GR) by considering gravity as warps and curves in the fabric of geometric space-time, and that geometry of space-time is described only by a metric. Our formalism is a straight-up implementation of the so called forward-method, where the pressure profile is computed while assuming empirical profiles for the mass, MHSE(r), and the electron density, ne(r), radial profiles which in our case are the standard NFW [5] and simplified Vikhlinin parametric model [6], respectively. Vikhlinin profile provides a more general parametric model in comparison to the β or the double β profiles and we validate that the former produces variation from the multiscale fitting in [7], of no more than ⇠ 5% for the ne(r) In this context, several previous works have implemented similar approach either using stacked clusters and/or having complementary weak lensing data [8,9,10].
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