The nature of red and blue quasars - a synergy of low-frequency radio and panchromatic surveys
Gabriela Calistro Rivera
An outstanding question on the nature of quasars is to understand whether the differences between red and blue quasars are explained by the AGN unification model or different evolutionary stages. I will present a systematic study on the low-frequency radio emission of red and blue SDSS quasars based on a synergy of the LOFAR deep field surveys and ancillary multi-wavelength surveys, from the radio-to-UV. We find a factor >3 enhancement of low-frequency radio detections in red quasars when compared to blue quasars. Additionally we investigate the shapes of radio SEDs of red and blue quasars, based on our multi-frequency radio data, and characterise the physical properties of their host galaxies. Our results, together with those from recent high-frequency radio studies from our team, suggest the differences between red and blue quasars do not simply arise from viewing angle effects, but suggest an evolutionary origin. This study highlights the huge potential of the synergy between radio and IR-to-UV multi-wavelength surveys to provide a better understanding on the nature of quasars.