Andrade-Santos, Felipe, van Weeren, Reinout J., Di Gennaro, Gabriella, Wittman, David, Ryu, Dongsu, Vir Lal, Dharam, Placco, Vinicius M., Fogarty, Kevin, Jee, M. James, Stroe, Andra, Sobral, David, Forman, William R., Jones, Christine, Kraft, Ralph P., Murray, Stephen S., Brüggen, Marcus, Kang, Hyesung, Santucci, Rafael, Golovich, Nathan, and Dawson, William. 2019. "Chandra Observations of the Spectacular A3411─12 Merger Event." The Astrophysical Journal, 887 31. https://doi.org/10.3847/1538-4357/ab4ce5.
We present deep Chandra observations of A3411─12, a remarkable merging cluster that hosts the most compelling evidence for electron reacceleration at cluster shocks to date. Using the {Y}{{X}}{--}M scaling relation, we find r 500 ∼ 1.3 Mpc, {M}500=(7.1 /- 0.7)× {10}14 {M}ȯ , {kT}=6.5 /- 0.1 {keV}, and a gas mass of {M}{{g},500}=(9.7 /- 0.1)× {10}13{M}ȯ . The gas mass fraction within r 500 is {f}{{g}}=0.14 /- 0.01. We compute the shock strength using density jumps to conclude that the Mach number of the merging subcluster is small (M≤slant {1.15}-0.09 0.14). We also present density, temperature, pseudo-pressure, and pseudo-entropy maps. Based on the pseudo-entropy map, we conclude that the cluster is undergoing a mild merger, consistent with the small Mach number. On the other hand, radio relics extend over Mpc scale in the A3411─12 system, which strongly suggests that a population of energetic electrons already existed over extended regions of the cluster.
