Chandra Detection of AN X-Ray Einstein Ring in PKS 1830-211

ABSTRACT We report the detection, using the Chandra X-ray observatory, of an X-ray Einstein Ring in the gravitational lens system PKS 1830-211. We find a significant correlation between the X-ray and radio morphologies suggesting the origin of the X-ray ring is synchrotron emission from the jet of the distant z= 2.51 lensed blazar. An analysis of the spectra of the individual images suggests significant differential absorption with most of the absorption ( NH(z = 0.886) ~ 2e22 cm-2) occuring towards the SW image. The Chandra observations of PKS 1830-211 were taken approximately one year apart and show significant spectral variablity. We present various mechanisms to explain this spectral variability. Our spectral-spatial analysis indicates a f_NE/f_SW flux ratio of ~ 1.1 consistent with that observed in the radio and infrared bands but significantly different from the recently reported estimate inferred from previous ASCA observations.