GMRT 610 MHz observations of galaxy clusters in the ACT equatorial sample

Understand

We present Giant Metrewave Radio Telescope 610 MHz observations of 14 Atacama Cosmology Telescope (ACT) clusters, including new data for nine.

• The sample includes 73\% of ACT equatorial clusters with $M_{500} > 5 \times 10^{14}\;M_\odot$.
• We detect diffuse emission in three of these (27$^{+20}_{-14}$\%): we detect a radio mini-halo in ACT-CL J0022.2$-$0036 at $z=0.8$, making it the highest-redshift mini-halo known; we detect potential radio relic emission in ACT-CL J0014.9$-$0057 ($z=0.533$); and we confirm the presence of a radio halo in low-mass cluster ACT-CL J0256.5+0006, with flux density $S_{610} = 6.3\;\pm\;0.4$ mJy.
• We also detect residual diffuse emission in ACT-CL J0045.9$-$0152 ($z=0.545$), which we cannot conclusively classify.