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 can not conclusively classify .
For systems lacking diffuse radio emission , we determine radio halo upper limits in two ways and find via survival analysis that these limits do not significantly affect radio power scaling relations .
Several clusters with no diffuse emission detection are known or suspected mergers , based on archival X-ray and/or optical measures ; given the limited sensitivity of our observations , deeper observations of these disturbed systems are required in order to rule out the presence of diffuse emission consistent with known scaling relations .
In parallel with our diffuse emission results , we present catalogs of individual radio sources , including a few interesting extended sources .
Our study represents the first step towards probing the occurrence of diffuse emission in high-redshift ( z \gtrsim 0.5 ) clusters , and serves as a pilot for statistical studies of larger cluster samples with the new radio telescopes available in the pre-SKA era .