Investigating AGN feedback in H$α$-luminous galaxy clusters: first Chandra X-ray analysis of Abell 2009

We analyze the X-ray and radio properties of the galaxy cluster Abell 2009 (z=0.152) to complete the in-depth study of a subsample of objects from the ROSAT Brightest Cluster Sample with relatively high X-ray flux and H$α$ line luminosity, which is a promising diagnostic of the presence of cool gas in the cluster cores. Our aim is to investigate the feedback from the AGN in the central galaxy and the ICM of relaxed clusters. In this work, we analyze archival data from JVLA and Chandra observations. We performed a morphological analysis of both the X-ray emission from the ICM of Abell 2009 and the radio emission from the AGN in the central galaxy. We also performed a spectral analysis of the X-ray emission to derive the global properties and radial profiles of the thermal gas. Our X-ray analysis confirms the expectations, based on the selection criteria, that Abell 2009 is a cool-core system. We estimate a cooling radius of 88 kpc within which the ICM is radiating its energy at rates of $L_{cool} \sim 4.4 \times 10^{44}$ erg s$^{-1}$. Radio observations of the central galaxy reveal a bright core surrounded by radio lobes on 30 kpc scales with a symmetric butterfly-shaped morphology. Although we did not detect any X-ray cavity at the position of the central radio lobes, we combined the volume of the lobes with the pressure of the surrounding ICM to derive the work done by the AGN on the gas to inflate them. By estimating a cavity age of about 20 Myr, this corresponds to a mechanical power of $\approx 10^{45}$ erg s$^{-1}$ which is sufficient to counterbalance the radiative cooling losses in Abell 2009. We finally discuss possible correlations between the global properties of the 18 objects from the BCS selection, finding in particular that the number of outbursts required to counterbalance the radiative ICM losses is linearly anticorrelated with the energy and power of the outburst.