A search for diffuse radio emission in the relaxed , cool - core galaxy clusters A 1068 , A 1413 , A 1650 , A 1835 , A 2029 , and Ophiuchus

Aims. We present results from sensitive, high dynamic range, observations to search for extended diffuse radio emission in relaxed and cool-core galaxy clusters. Methods. For this purpose we performed deep 1.4 GHz Very Large Array observations, of A1068, A1413, A1650, A1835, A2029, and complemented our dataset with archival observations of Ophiuchus. Results. We find that in the central regions of A1835, A2029, and Ophiuchus the dominant radio galaxy is surrounded by a diffuse low-brightness radio emission that takes the form of a mini-halo. We detect no diffuse emission in A1650, at a surface brightness level of the other mini-halos. We find low significance indications of diffuse emission in A1068 and A1413, however to be classified as mini-halos they require further investigation, possibly with an even better signal-to-noise ratio. In addition, in the Appendix we report on the serendipitous detection of a giant radio galaxy with a total extension of ∼1.6 Mpc in size.