The SRG/eROSITA All-Sky Survey: A comprehensive X-ray analysis of the Hydra I galaxy cluster

The Hydra I galaxy cluster (Abell 1060) is a nearby example of a low-temperature cluster that exhibits intermediate cool core and non-cool core properties. We aim to extend the characterization of the intracluster medium (ICM) properties at least until $R_{200}$ and study the correlation between the X-ray emission and non-thermal emission within $R=0.15$$R_{500}$, and optical/IR galaxy distribution beyond $R_{200}$. We used data from the first four SRG/eROSITA All-Sky Surveys and an archival Chandra observation to image the X-ray emission from Abell 1060. We also used multiwavelength data from TGSS (radio), 2MASS (IR), and NED (optical) to investigate the non-thermal emission, 2D galaxy distribution, and its redshift evolution, respectively. The surface brightness and spectral analyses are also extended until 3$R_{200}$ and $R_{200}$, respectively, following a detailed cosmic X-ray background (CXB) analysis. Our fully corrected eROSITA image showcases a relaxed ICM morphology within $R_{500}$. We detect two weak ICM shocks with Mach number $M\approx 1.5$ near the central galaxy NGC 3311 that coincide with diffuse radio emission along the line of sight. Furthermore, we detect multiple soft X-ray excesses with high spatial correlation with the 2D optical galaxy distribution beyond $R_{200}$. In particular, the excess in the north has a significance of $5.8\sigma$ above the local CXB level. This suggests that Abell 1060’s outskirts are actively accreting baryons. We also estimate the average ICM temperature and metallicity of $⟨k_{\mathrm{B}}T⟩=2.27\begin{array}{c}+0.15\\ -0.11\end{array}$ keV and $⟨Z⟩=0.19\begin{array}{c}+0.05\\ -0.03\end{array}{Z}_{\odot }$, respectively, from the 0.2-0.5$R_{500}$ annulus. Overall, the temperature profile is broadly consistent with the average temperature profiles from hydrodynamical simulation and Suzaku between 0.28$R_{200}$ and $R_{200}$.