Power spectrum estimation methods on intracluster medium surface brightness fluctuations

TL;DR

This paper evaluates methods for estimating the power spectrum of intracluster medium surface brightness fluctuations from 2D projections, using simulations to compare their accuracy against the true 3D spectrum and addressing noise reduction techniques.

Contribution

It introduces and compares different power spectrum estimation methods on simulated 2D data, highlighting their effectiveness in recovering the 3D turbulence spectrum.

Findings

Certain methods accurately recover the 3D power spectrum

Noise reduction improves spectral estimation quality

Projection effects significantly impact turbulence measurements

Abstract

Accurate estimation of galaxy cluster masses is a central problem in cosmology. Turbulence is believed to introduce significant deviations from the hydrostatic mass estimates. Estimation of turbulence properties is complicated by projection of the 3D cluster onto the 2D plane of the sky, and is commonly done in the form of indirect probes from fluctuations in the X-ray surface brightness and Sunyaev-Zeldovich effect maps. In this paper, we address this problem using simulations. We examine different methods for estimating the power spectrum on 2D projected fluctuation data, emulating data projected onto a 2D plane of the sky, and comparing them to the original, expected 3D power spectrum. Noise can contaminate the power spectrum of ICM observations, so we also briefly compare a few methods of reducing noise in the images for better spectral estimation.