English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

We present a multi-wavelength analysis of two highly magnified stronggravitationally lensed galaxies, CLASS B0712+472 and CLASS B1608+656, atredshifts $1.34$ and $1.394$, respectively, using new VLBI and archival HSTobservations. We reconstruct the positions of the radio and optical emissionswith their uncertainties using Monte Carlo sampling. We find that in CLASSB0712+472 the optical and radio emissions are co-spatial within $2\pm5$ mas($17\pm 42$ pc at redshift of 1.34). But, in CLASS B1608+656, we reconstruct anoptical-radio offset of $25\pm16$ mas ($214\pm137$ pc at redshift of 1.394),the smallest offset measured for an AGN at such high redshift. The spectralfeatures indicate that CLASS B1608+656 is a post-merger galaxy, which, incombination with the optical-VLBI offset reported here, makes CLASS B1608+656 apromising candidate for a high-$z$ offset-AGN. Furthermore, the milliarcsecondangular resolution of the VLBI observations combined with the precise lensmodels allow us to spatially locate the radio emission at $0.05$ mas precision($0.4$ pc) in CLASS B0712+472, and $0.009$ mas precision ($0.08$ pc) in CLASSB1608+656. The search for optical-radio offsets in high redshift galaxies willbe eased by the upcoming synoptic all-sky surveys, including E-ELT and SKA,which are expected to find $\sim 10^5$ strongly lensed galaxies, opening an eraof large strong lensing samples observed at high angular resolution.

Constraining VLBI-optical offsets in high redshift galaxies using strong gravitational lensing