2026 Project Description

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Gas and Stellar Size of AGN host galaxies

Keywords:

Supervisors

Bovornpratch Vijarnwannaluk, Shoichiro Mizukoshi, Chen Chian-Chou, Wang Wei-Hao,
Find out more about supervisors on ASIAA website

Task Description and Goals

Active galactic nuclei represent the growth phase of massive black holes in the universe. Several pathways have been suggested for the triggering and transportation of gas towards the nuclear region of galaxies. Some pathways involve external forces, such as galaxy mergers or gas streams, while some pathways invoke internal processes such as violent disk instabilities. These events “compact” the gas, fueling AGN, starformation, and dust production in a galaxy.

Among our sample of AGN host galaxies, J100034+020302.12 ( COSMOS_4_386, Laloux et al. 2022) has been identified as an active galaxy via the detection of luminous X-ray emission. In addition, it has CO J(3-2) observations from ALMA as part of the AS2COSPEC program (AS2COS0068.1, Chen et al. 2022). JWST imaging shows much fainter detection in shorter wavelengths, which probe the rest-frame optical, implying heavy amounts of dust in the galaxy. Estimates of X-ray absorption also support heavy obscuration. One explanation is that J100034 is a result of merging galaxies, which can result in compaction of molecular gas. Such a process can explain the large amounts of dust and gas, as well as strong AGN activity.

As part of the project, the student will perform the following tasks

1. Measure the size of the stellar component using JWST imaging with Galfit
2. Measure molecular size traced by CO images from ALMA with CASA
3. Discuss the extent and correspondence of the stellar and molecular gas distribution.
4. Construct a discussion with the current literature, summarize, and prepare a presentation.

By the end of this project, the students are expected to obtain basic knowledge of galaxy formation and AGN activity, and basic technical skills of performing size measurements using Galfit and CASA.

Required Background

Basic knowledge of physics and mathematics. Additional knowledge of cosmology and galaxies would be an asset. Basic knowledge and skills of computer programming would be desirable.