# Cavities, shocks and a cold front around 3C 320

## TL;DR

This study analyzes Chandra X-ray observations of galaxy cluster hosting 3C 320, revealing cavities, shocks, and a cold front, and assesses their energetic balance and impact on cooling and star formation.

## Contribution

First detailed X-ray analysis of 3C 320 revealing cavities, shocks, and cold front, and their implications for cluster energetics and cooling processes.

## Key findings

- Detected X-ray cavities with significant energy and age.
- Identified weak shocks with Mach numbers around 1.6-1.8.
- Found a cold front likely caused by a surface brightness edge.

## Abstract

We present results obtained from the analysis of a total of 110 ks Chandra observations of 3C 320 FR II radio galaxy, located at the centre of a cluster of galaxies at a redshift $z=0.342$. A pair of X-ray cavities have been detected at an average distance of $\sim$38 kpc along the East and West directions with the cavity energy, age and total power equal to $\sim$7.7$\times$10$^{59}$ erg, $\sim$7$\times$10$^7$ yr and $\sim$3.5$\times$10$^{44}$ erg s$^{-1}$, respectively. The cooling luminosity within the cooling radius of $\sim$100 kpc was found to be $L_{cool} \sim8.5\times10^{43}$ erg s$^{-1}$. Comparison of these two estimates implies that the cavity power is sufficiently high to balance the radiative loss. A pair of weak shocks have also been evidenced at distances of $\sim$47 kpc and $\sim$76 kpc surrounding the radio bubbles. Using the observed density jumps of $\sim$1.8 and $\sim$2.1 at shock locations along the East and West directions, we estimate the Mach numbers ($\mathcal{M}$) to be $\sim$1.6 and $\sim$1.8, respectively. A sharp surface brightness edge was also detected at relatively larger radius ($\sim$80 kpc) along the South direction. Density jump at this surface brightness edge was estimated to be $\sim$1.6 and is probably due to the presence of a cold front in this cluster. The far-infrared luminosity yielded the star formation rate of 51 M$_{\odot}$ yr$^{-1}$ and is 1/4$^{th}$ of the cooling rate ($\dot{M}$ $\sim$ 192 M$_{\odot}$ yr$^{-1}$).