Skip to main content

Research Repository

Advanced Search

Hydrodynamic simulations of the Disc of Gas Around Supermassive black holes (HDGAS) -II; The transition from neutral atomic to molecular gas phases

Raouf, Mojtaba; Viti, Serena; Karimi, Reihaneh; Richings, Alexander J

Authors

Mojtaba Raouf

Serena Viti

Reihaneh Karimi

Profile image of Alex Richings

Dr Alex Richings A.J.Richings@hull.ac.uk
Lecturer in Data Science, Artificial Intelligence and Modelling



Abstract

We use HDGAS hydrodynamic simulations to study the impact of active galactic nucleus (AGN) feedback on the conversion of atomic-gas to molecular-gas within the circumnuclear-disc (CND) of a typical AGN-dominated galaxy. The comparison of CI, CII, and CO line intensities and their ratios in the HDGAS post-processing radiative-transfer analysis reveals the complex interplay between AGN-activity, cold molecular gas properties, and the physical processes governing the evolution of star-formation in galaxies. Our results demonstrate that the CI/CO intensity ratio serves as a reliable indicator of the atomic-to-molecular gas transition. We present the probability distribution function (PDF) and abundance trends of various metal species related to molecular H2 gas, highlighting differences in clumpiness and intensity maps between AGN feedback and NoAGN models. The profile of the integrated intensity (moment-0) maps shows that the AGN-feedback model exhibits a lower CI/CO intensity ratio in the vicinity of the supermassive black hole (< 50 pc), indicating a smaller atomic-gas abundance and the presence of positive AGN-feedback. Our simulations have successfully predicted the presence of faint-CO emissions extending to larger radii from the galactic center. We also explore the relationships between CII/CO and CI/CII intensity ratios, as well as the ratios versus CO intensity, which provides insights into the ‘CO-dark’ issues. One notable feature in the later time-scale of the AGN model is the presence of a ‘CO-dark’ region, where the intensity of CO emission (I_CO) is depleted relative to the H2 column density (N_H2) compared to the NoAGN model.

Citation

Raouf, M., Viti, S., Karimi, R., & Richings, A. J. (2025). Hydrodynamic simulations of the Disc of Gas Around Supermassive black holes (HDGAS) -II; The transition from neutral atomic to molecular gas phases. Monthly notices of the Royal Astronomical Society, 539(2), 1516-1527. https://doi.org/10.1093/mnras/staf557

Journal Article Type Article
Acceptance Date Apr 2, 2025
Online Publication Date Apr 4, 2025
Publication Date May 1, 2025
Deposit Date Apr 16, 2025
Publicly Available Date Apr 28, 2025
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Oxford University Press
Peer Reviewed Peer Reviewed
Volume 539
Issue 2
Pages 1516-1527
DOI https://doi.org/10.1093/mnras/staf557
Keywords ISM: molecules; Galaxies: active; Galaxies: evolution; Galaxies: Seyfert
Public URL https://hull-repository.worktribe.com/output/5130713

Files

Published article (2.7 Mb)
PDF

Publisher Licence URL
http://creativecommons.org/licenses/by/4.0

Copyright Statement
© 2025 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.






You might also like



Downloadable Citations