Deep Chandra Observations of A2495: A Possible Sloshing-regulated Feedback Cycle in a Triple-offset Galaxy Cluster

Abstract

We present the analysis of new, deep Chandra observations (130 ks) of the galaxy cluster A2495. This object is known for the presence of a triple offset between the peaks of the intracluster medium (ICM), the brightest cluster galaxy (BCG), and the warm gas glowing in H α line. The new Chandra data confirm that the X-ray emission peak is located at a distance of ∼6.2 kpc from the BCG, and at ∼3.9 kpc from the H α emission peak. Moreover, we identify two generations of X-ray cavities in the ICM, likely inflated by the central radio galaxy activity. Through a detailed morphological and spectral analysis, we determine that the power of the active galactic nucleus (AGN) outbursts ( P _cav = 4.7 ± 1.3 × 10 ^43 erg s ^−1 ) is enough to counterbalance the radiative losses from ICM cooling ( L _cool = 5.7 ± 0.1 × 10 ^43 erg s ^−1 ). This indicates that, despite a fragmented cooling core, A2495 still harbors an effective feedback cycle. We argue that the offsets are most likely caused by sloshing of the ICM, supported by the presence of spiral structures and a probable cold front in the gas at ∼58 kpc east of the center. Ultimately, we find that the outburst interval between the two generations of X-ray cavities is of the order of the dynamical sloshing timescale, as already hinted from the previous Chandra snapshot. We thus speculate that sloshing may be able to regulate the timescales of AGN feedback in A2495, by periodically fueling the central AGN.

Keywords

• Galaxy clusters
• Abell clusters
• Active galactic nuclei
• Cooling flows
• Intracluster medium