CHEX-MATE: Constraining the origin of the scatter in galaxy cluster radial X-ray surface brightness profiles

We investigate the statistical properties and origin of scatter within spatially resolved surface brightness profiles CHEX-MATE sample, formed by 118 galaxy clusters selected via SZ effect. These objects have been drawn from Planck catalogue cover a wide range masses, M$_{500}=[2-15] \times 10^{14} $M$_{\odot}$, redshift, z=[0.05,0.6]. derived emission measure determined full sample. found that there is critical scale, R$\sim 0.4 R_{500}$, which morphologically relaxed disturbed object diverge. The median each sub-sample differs factor $\sim 10$ at $0.05\,R_{500}$. There are no significant differences between mass- redshift-selected sub-samples once proper scaling applied. compare with sample 115 Three Hundred suite cosmological simulations. simulated systematically steeper than those observations. For first time, simulations were used to break down components causing profiles. investigated behaviour due object-by-object variation. high scatter, approximately 110%, $R<0.4R_{500}$ genuine difference distribution gas in core. intermediate $R_{500} =[0.4-0.8]$, characterised minimum value on order 0.56, indicating region where cluster closest self-similar regime. Larger scales increasing complex spatial gas. Also for we verify projection effects smaller variation all considered scales. [abridged]