Chinese Academy of Science South America Center for Astronomy

A Massive Barred Spiral Galaxy at z = 5.102 Discovered by JWST

Abstract We report M1149-BSG-z5, a barred spiral galaxy at z = 5.102, identified in the parallel field of MACS J1149+2223 with JWST and the Hubble Space Telescope. M1149-BSG-z5 is the highest-redshift barred galaxy candidate to date. Both isophote ellipse fitting and structural m...

JWST Nebular Spectroscopy of SN 2023qov: Circumstellar Dust Emission in a Normal Type Ia Supernova

Abstract We present panchromatic observations of the Type Ia supernova (SN Ia) 2023qov, ranging from ∼2 weeks before to ∼1 yr after maximum light. JWST near- and mid-infrared spectra at +276 and +363 days show ∼400 K dust emission that cools by ∼75 K between epochs, the first una...

Stellar masses of optically dark galaxies: uncertainty introduced by the attenuation law and star-formation histories

Abstract Recent studies using JWST have suggested that some high-redshift galaxies may be ultra-massive, thereby challenging standard models of early galaxy formation. We analyse the stellar masses using different modelling assumptions and in conjunction with new data of three ga...

Dust Substructures and Line Perturbations driven by a Forming Planet in J16120

Abstract Hints of planet formation have been independently reported within the gap of the disc around 2MASS J16120668-301027 from millimetre continuum, infrared, and Hα observations. In this work, we present new evidence for ongoing planet formation based on Atacama Large Millime...