High Resolution spatial analysis of a z $\sim$ 2 lensed galaxy using adaptive coadded source-plane reconstruction

TL;DR

This study uses advanced lens modeling and adaptive coadded source-plane reconstruction to achieve high-resolution spatial analysis of a z~2 lensed galaxy, revealing detailed morphology and kinematics indicative of an ongoing merger.

Contribution

It introduces a novel adaptive coadded source-plane reconstruction technique that enhances resolution and component detection in lensed galaxy analysis.

Findings

Resolved galaxy features down to 170 pc scale.

Detected multiple components in velocity gradient.

Identified signs of an ongoing merger.

Abstract

We present spatially resolved analysis of a lensed galaxy, SDSS1958+5950 at $z = 2.225$, from the Cambridge Sloan Survey of Wide Arcs in the Sky (CASSOWARY). We use our new high resolution imaging data to construct a robust lens model for the galaxy group at $z = 0.214$. We employ the updated lens model to combine the Integral Field Spectrographic observations on two highly distorted images of the lensed target. We adopt a forward-modeling approach to deconvolve the effects of point spread function from the combined source-plane reconstruction. The approach is adapted to the lens model magnification and enables a resolution of $\sim$170 pc in the galaxy-source plane. We propose an ongoing merger as the origin of the lensed system on the basis of its source-plane morphology, kinematics and rest-frame emission line ratios. Using our novel technique of adaptive coadded source plane reconstruction, we are able to detect different components in the velocity gradient that were not seen in previous studies of this object, plausibly belonging to different components in the merging system.