On the radio -- X-ray luminosity correlation of radio halos at low radio frequency - Application of the turbulent re-acceleration model

Understand

In this paper we show expectations on the radio--X-ray luminosity correlation of radio halos at 120 MHz.

• According to the "turbulent re-acceleration scenario", low frequency observations are expected to detect a new population of radio halos that, due to their ultra-steep spectra, are missed by present observations at ~ GHz frequencies.
• These radio halos should also be less luminous than presently observed halos hosted in clusters with the same X-ray luminosity.
• Making use of Monte Carlo procedures, we show that the presence of these ultra-steep spectrum halos at 120 MHz causes a steepening and a broadening of the correlation between the synchrotron power and the cluster X-ray luminosity with respect to that observed at 1.4 GHz.