27 March 2026
Niels Bohr Bygningen 1
Europe/Copenhagen timezone
Abstract submission and Registration is now OPEN!

Tracing the dust and ISM properties of distant quiescent galaxies with JWST and ALMA

27 Mar 2026, 16:05
1h 55m
Canteen area (Niels Bohr Bygning 1)

Canteen area

Niels Bohr Bygning 1

Jagtvej 132 2200 Copenhagen

Description

In studying the evolution of galaxies, we observe a clear bimodality in both their morphology and colour space, discerning two distinct populations: blue, star-forming galaxies with a younger, UV-bright stellar population, and red, early-type galaxies, whose star formation has halted---so-called quiescent galaxies. Understanding the halting of star formation (termed quenching) is therefore vital for building an overall picture of galaxy evolution.

Furthermore, recent observations using the James Webb Space Telescope have extended the discovery frontier of quenched, "red-and-dead" galaxies to much earlier in cosmic time than expected, back to when the Universe was less than 700 million years old. This breakthrough offers a timely opportunity to investigate what governs quenching at high redshift, and how it differs from quenching in the present-day universe.

This work focus on examining the dust and gas properties of high-redshift quenched galaxies, with the goal of understanding the impact of associated feedback mechanisms---such as those from active galactic nuclei (AGN)---on the interstellar medium. We utilise ALMA continuum data to examine dust retention in quiescent systems, and JWST/NIRSpec spectroscopy to characterise AGN activity through emission line diagnostics. By studying this quiescent population, we aim to shed light on the mechanisms that drive quenching in the early universe, and contribute to our understanding of how galaxies are born, live, and eventually die.

Field of study Astrophysics
Supervisor Sune Toft, William Baker, Minju Lee

Author

Mark Beyer Stjerne (Niels Bohr Institute, University of Copenhagen)

Presentation materials

There are no materials yet.