A Deep Chandra View of A2597: Bubbles, Shocks, Cold Fueling, and a Plasma Depletion Layer

Abstract To examine how active galactic nucleus (AGN) feedback shapes the intracluster medium (ICM) and fuels black hole accretion in the cool-core galaxy cluster A2597, we present deep (∼600 ks) Chandra X-ray observations complemented by archival GMRT radio and SINFONI near-infrared data. Radio-mode AGN activity has inflated seven X-ray cavities and driven one to three potential weak shocks ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi class="MJX-tex-calligraphic" mathvariant="script">M</mml:mi> <mml:mo>∼</mml:mo> <mml:mn>1.05</mml:mn> <mml:mo>−</mml:mo> <mml:mn>1.14</mml:mn> </mml:math> ) extending to ∼150 kpc, suggesting recurrent outbursts occurring on ∼10 7 yr timescales. We also detect a narrow, ∼57 kpc X-ray surface brightness deficit—a potential plasma depletion layer—likely shaped by residual sloshing motions that amplified magnetic fields and/or displaced gas within the cluster core. Although the AGN injects ∼10 44 erg s −1 of energy, comparable to the cluster’s cooling luminosity, radiative cooling persists at ∼15 M ⊙ yr −1 , replenishing the billion-solar-mass cold gas reservoir at the heart of the brightest cluster galaxy. Sustaining this level of activity requires a continuous fuel supply, yet the estimated Bondi accretion power (∼2 × 10 43 erg s −1 ) falls an order of magnitude short of the observed cavity power, suggesting that “hot” gas fueling is insufficient. Instead, archival Atacama Large Millimeter/submillimeter Array observations continue to support a chaotic cold accretion scenario, where turbulence-driven condensation fuels the AGN at rates exceeding Bondi accretion, sustaining a self-regulated feedback cycle that repeatedly shapes the core of A2597.