Feng-Wu Sun

A sub-100 pc view at z~5 of a Multiply-Imaged Massive Quiescent Galaxy

Recent James Webb Space Telescope spectroscopic surveys reveal an abundance of rapidly assembled early galaxies in the first billion years. Cosmological simulations struggle to reproduce this population because models require a rapid, highly efficient conversion of baryons into stars followed by an abrupt cessation of...

A Steep-extinction Quasi-stellar Object at z = 4.6: JWST Evidence for Abundant Small Dust Grains

The rapid accumulation of massive dust reservoirs in the early Universe remains a major challenge in astrophysics. While core-collapse supernovae can inject large dust grains (a ≳ 0.1 μm) on short timescales, explaining the total dust budgets in the early Universe likely requires efficient grain growth in the interstel...

An Archival Calibration of JWST/MIRI Prism Wide-Field Slitless Spectroscopy: Methodology, Performance, and a Mid-Infrared Spectral Atlas of Galaxies at $z=0-4$ in the GOODS-N/S Fields

Through the Low Resolution Spectroscopy (LRS) observing mode of JWST/MIRI, the P750L prism disperses the entire ~70"$\times$110"imager field, turning MIRI into a wide-field slitless spectrograph (WFSS) at 5-14 $\mu$m with spectral resolution $R\sim100$. Using archival MIRI LRS data taken in the GOODS-N/S deep fields an...

The first statistical study of over 100 magnified stellar events at a redshift z ≈ 0 . 725 with JWST

SN Helios: A Multiply Imaged Type II Supernova Opening Time-Delay Cosmography beyond redshift of 3

We report the discovery and spectroscopic confirmation of SN Helios, a strongly lensed, multiply imaged Type II supernova (SN) at $z=3.34$ behind the galaxy cluster RXC J0018.5+1626. The transient was identified as a red F150W-dropout source (F277W = 26.1 mag) in JWST/NIRCam imaging taken on 2026 July 3 for the VENUS s...