Resolving pc-scale X-ray jets and dual quasars via gravitational lensing

Offset and dual supermassive black holes (SMBH) are expected to be found in the early universe as galaxies evolve and merge. X-ray emission is an ideal method to detect SMBH that are accreting gas. However, the resolution of X-ray telescopes do not allow separation of sources that are less than a few kpc at cosmological distances. We use gravitational lenses as telescopes to compare optical and radio quasar locations with the location of X-ray emission, on milli-arcsec scales. We report results of analysis of four sources selected inside and near to the caustic, that are the most magnified and spatially amplified, and so that the four images can be used to create a self-consistent reference frame. For the two quasars CLASS B0712+472 and CLASS B1608+656 at Z~1.3, we directly measure locations to within about 11 mas (<90 pc, oneσ) of the corresponding radio sources. Observations of thirteen quadruply lensed sources in the Chandra archive span more than 5 years. We report on a study of 11 separate Chandra observations of HE0435-1223 spanning 14.3 years. This allows use of the “varstrometry” method to search for a dual AGN system. We show that MG B2016+112, at z=3.273, must contain two distinct X-ray emitting regions. One X-ray source is just inside the caustic, with magnification of about 300. It is within 40 pc of a radio counterpart. The system is either a dual AGN or an AGN plus an X-ray jet hotspot, in either case with separations of a few hundred pc. Using our methods, we expect X-ray observations from selections of the ~10⁵ lenses that will be discovered, e.g., by the Rubin Observatory and SKA, to reveal statistically significant samples of offset and binary AGN’s at large redshifts.