A multiwavelength follow-up study of the enigmatic 3C 220.3 lensed system

During a 2012 survey with the Herschel Space Observatory, the radio galaxy 3C 220.3 (\(z=0.685\)) was discovered to be gravitationally lensing a submillimeter galaxy (SMG) at a redshift of \(z=2.221\). Initial lens models indicated that 3C 220.3 (source A) is part of a double-lens system with a third object of unknown redshift (source B). Since then, deeper data from the Chandra X-Ray Observatory and the Hubble Space Telescope (HST) have been obtained, showing diffuse X-ray emission and a full Einstein ring in the optical/infrared bands. Using the new three-color HST data, we report updated stellar masses for sources A and B (\(M_A^* \sim \left(1.1^{+ 17}_{-0.17}\right)\times 10^{10} M_{\odot}\) and \(M_B^* \sim \left(5.4^{+90}_{-1.1} \right)\times 10^{9} M_{\odot}\)), restframe blackbody temperatures for sources A and B and the SMG (\(T_{A\text{,rest}} \sim 4430 \textrm{ K}\), \(T_{B\text{,rest}} \sim 4340 \textrm{ K}\), and \(T_{\text{SMG,rest}} \sim 8570 \textrm{ K}\)), and preliminary dark matter fractions for sources A and B (\(f_A \sim 0.97_{-0.48}^{+0.01}\) and \(f_B \sim 0.96_{-0.75}^{+0.01}\)). We also report the first measurements of the internal magnetic fields of 3C 220.3's radio lobes, which have strengths of approximately \(1.5 - 3 \textrm{ nT}\). These values are a factor of \(\sim 2-3\) below the strengths of the corresponding equipartition field. Updated lens modeling using the more recent Chandra and HST data is forthcoming and will generate a new reconstruction of the SMG and provide improved total masses for dark matter fraction estimations.