collaborators

6 papers

astro-ph.GA2025

An Active Galaxy Cluster Merger at Cosmic Noon Revealed by JWST Weak Lensing and Multiwavelength Probes

Zachary P. Scofield, Kyle Finner, Hyungjin Joo +8

The galaxy cluster XLSSC~122 is a rare system at , hosting surprisingly evolved member galaxies when the Universe was only one-third of its present age. Leveraging deep J…

astro-ph.GA2025

JWST Discovery of Strong Lensing from a Galaxy Cluster at Cosmic Noon: Giant Arcs and a Highly Concentrated Core of XLSSC 122

Kyle Finner, Sangjun Cha, Zachary P. Scofield +9

Our observations with the James Webb Space Telescope have made the remarkable discovery of strong gravitational lensing arcs from XLSSC 122 () - setting the record for the…

astro-ph.GA2025

MrMARTIAN: A Multi-resolution Mass Reconstruction Algorithm Combining Free-form and Analytic Components

Sangjun Cha, M. James Jee

We present (Multi-resolution MAximum-entropy Reconstruction Technique Integrating Analytic Node), a new hybrid strong lensing (SL) modeling algorithm. By incorpor…

astro-ph.GA2025

Is Earendel a Star?: Investigating the Sunrise Arc Using JWST Strong and Weak Gravitational Lensing Analyses

Zachary P. Scofield, M. James Jee, Sangjun Cha +1

The galaxy cluster WHL J013719.8-08284 at exhibits a strong-lensing feature known as the Sunrise Arc, which hosts the candidate star Earendel at , the mo…

astro-ph.GA2025

A High-Caliber View of the Bullet Cluster Through JWST Strong and Weak Lensing Analyses

Sangjun Cha, Boseong Young Cho, Hyungjin Joo +5

The Bullet Cluster (1E 0657-56) is a key astrophysical laboratory for studying dark matter, galaxy cluster mergers, and shock propagation in extreme environments. Using new JWST im…

astro-ph.CO2025

Cosmology with supernova Encore in the strong lensing cluster MACS J01382155: photometry, cluster members, and lens mass model

S. Ertl, S. H. Suyu, S. Schuldt +23

The strongly lensed Supernova (SN) Encore at a redshift of , discovered behind the galaxy cluster MACS J01382155 at , provides a rare opportunity for time-de…