Abell 2244 multi-component radio emission

We also used mock LOFAR observations to investigate contamination of the emission from faint radio sources. We find an integrated spectral index of alpha^1279^_144_=0.9+/-0.1 for both components, where only the radio halo shows spectral steepening at higher frequencies. These values are comparable with the spectral indices observed in disturbed massive clusters.

The outer component does not follow the same radio X-ray correlation as the radio halo, which suggests a different physical origin. By analysing the physical and morphological properties of the diffuse emission, we find that the characteristics of the outer component of the emission are intermediate between those of radio haloes and of known megahaloes. Hence, we speculate that the source is either a morphologically disturbed radio halo, caused by a minor merger interaction, or a megahalo but we cannot reach a final classification.

From the mock observations, we find that it is unlikely that the emission is caused by faint sources at low resolutions.