GW023
GW023A
The properties of ionised mediums within galaxies are important for studying star formation and galaxy formation, but measuring the electron density of ionised mediums in high-redshift galaxies is very challenging. A multiple-image strong lensing system offers a unique view into the ionised medium in the lensing galaxy. Lensed images show different views of the same source affected by scatter broadening and free-free absorption. The quadruple lens system B0128+437 is affected by both scattering and free-free absorption. We request high-sensitivity multi-frequency global VLBI observations to image the scatter-broadened lensed image in B0128+437, and resolve the core-jet structure represented by the three subcomponents in each lensed image. Taking advantage of scattering size scaled by the lensing magnification, the inhomogeneous ionised scattering medium can be resolved down to sub-parsec physical scales at redshift 1.145. The constraints from the image subcomponents will tightly constrain the lens model. Additionally, these data will quantify the flux ratio anomaly caused by free-free absorption. Modelling such propogation effects in this lens system will reduce the systematics for the constraints on the nature of dark matter given by this system.
Observation pages at the EVN archive:
This data is part of the archive of VLBI data maintained by JIVE on behalf of the EVN, a network of radio telescopes located primarily in Europe and Asia, with additional antennas in South Africa. The EVN archive itself has the DOI https://doi.org/10.17616/R3Z197