The plethora of diffuse emission in Abell 2034 revealed by MeerKAT polarization observations

We present MeerKAT observations of the galaxy cluster Abell 2034, a massive ( M 500 = 5.21 ⋅ 10 14 M ⊙ ) nearby cluster in a merging state. Previous observations at 144 MHz have shown that the cluster exhibits a plethora of diffuse emission, with multiple diffuse sources of uncertain classification because of the lack of spectral and polarimetric observations. MeerKAT multifrequency observations, centered at 816 MHz and 1.28 GHz, together with archival low-frequency LOFAR observations at 144 MHz have enabled us to shed light on the properties of these sources. The polarization properties and spectral index information lead us to conclude that the cluster hosts one radio relic, a source with a very steep spectrum, previously classified as candidate relic, along with filaments of very steep emission around the tailed radio galaxies identified at low frequencies. The presence of a radio halo is confirmed and its spectrum displays hints of a curvature between 144 MHz ad 1.28 GHz. We used the polarimetric data in the L band, together with the model of the gas density derived from X-ray observations to constrain the magnetic field in the intracluster medium. We assumed a radially symmetric magnetic field model, whose strength declines with the cluster gas density as B ( r )∝ n e ( r ) 0.5 . We normalized its strength within R 500 ( B 500 ). We found that B 500 = 1 μG best explains the Faraday depth properties of the cluster, although the detection of sources close to the cluster center would be crucial to discriminate among different values. We conclude that the cluster Abell 2034 exhibits diffuse emission with complex morphologies that do not follow the historical categories of halos and relics. Deep multifrequency and polarimetric observations are fundamental to understanding their origin.