X-Ray surface brightness and gas density fluctuations in the Coma cluster

Understand

X-ray surface brightness fluctuations in the core ($650 \times 650$ kpc) region of the Coma cluster observed with XMM-Newton and Chandra are analyzed using a 2D power spectrum approach.

• The resulting 2D spectra are converted to 3D power spectra of gas density fluctuations.
• Our independent analyses of the XMM-Newton and Chandra observations are in excellent agreement and provide the most sensitive measurements of surface brightness and density fluctuations for a hot cluster.
• We find that the characteristic amplitude of the volume filling density fluctuations relative to the smooth underlying density distribution varies from 7-10% on scales of $\sim$500 kpc down to $\sim$5% at scales $\sim$ 30 kpc.