Merging cold front and AGN feedback in the peculiar galaxy cluster Abell 2626

This paper presents the analysis of a combined 134 ks {\it Chandra} data of a peculiar galaxy cluster Abell 2626. This study confirms the earlier detection of the east cavity at $\sim$13 kpc and reports detection of a new cavity at $\sim$39 kpc on the west of the X-ray peak. The average mechanical power injected by the AGN outburst ${\rm P_{cav} \sim 6.6 \times 10^{44}\, erg\, s^{-1}}$ is $\sim$29 times more than required to compensate the cooling luminosity ${\rm L_{cool} = 2.30 \pm 0.02 \times 10^{43} {\rm~erg\ s}^{-1}}$. The edges in the SB on the west and south-west at $\sim$36 kpc and 33 kpc, respectively, have the gas compressions of 1.57$\pm$0.08 and 2.06$\pm$0.44 and are spatially associated with the arcs in the temperature and metallicity maps due to the merging cold fronts. The systematic study of the nuclear sources exhibited dramatic changes over the span of ten years. The NE source that emitted mostly in the soft band in the past disappeared in the recent observations. Instead, an excess emission was seen at $2.2"$ on its west and required an unrealistic line of sight velocity of $\sim$ $675\times{}c$ if is due to its movement. The count rate analysis and spectral analysis exhibited a change in the state of the SW source from a soft state to the hard due to the change in the mass accretion rate. No such spectral change was noticed for the NE source.

Sonali K. Kadam, Satish S. Sonkamble, Pramod K. Pawar, Madhav K. Patil · 2019