SALVAGE II: no systematic molecular gas depletion in the central 2 kpc of AGN hosts
Abstract
In cosmological simulations, active galactic nuclei (AGN) feedback is found to be necessary for the shutdown of galaxy-wide star-formation by heating and/or removing molecular gas. However, at low-redshift, there is little evidence of systematic large-scale gas depletion. Some recent observations have found molecular gas depletion in AGN hosts, but limited to the central regions of galaxies. In this work, we use the SDSS-ALMA Legacy-Value Archival Gas Exploration (SALVAGE) dataset, which provides molecular gas and stellar mass measurements from the inner (r < 0.5-2 kpc) and outer region of the galaxy. Using AGN diagnostics from optical emission lines, mid-IR colour, and X-ray luminosity, we identify 70 AGN at z < 0.07 and inspect their central molecular gas reservoirs with a suite of metrics compared to non-AGN controls. In agreement with global studies of low-z AGN hosts, we find that, compared to matched non-AGN, the central regions of AGN have equal molecular gas fractions and enhanced molecular gas surface densities. For the first time, we explore the central gas reservoirs of AGN identified with different selection criteria and find two optical AGN classes that show a tentative 1.5σ and 1.8σ signal of central molecular gas depletion. However, the AGN with central gas depletion do not occupy any specific region of the parameter space, such as AGN luminosity, that can provide a physical explanation for the depletion. If AGN are responsible for large-scale gas removal, the lack of systematic gas depletion in SALVAGE AGN sets an upper limit on the physical scale of the gas removal while the AGN remains observable.
Related
- GASTRO−BH: Effects of a Central Black Hole in GSE-like Dwarf-galaxy Mergers Around Milky Way-like Hosts
- Central stellar depletion in the Draco dwarf from Subaru photometry
- Isotopic ratios as probes of star formation and the origin of molecular gas in the Central Molecular Zone
- The Central Molecular Zone of our Galaxy, a chemical complexity factory: first interstellar detections of molecules towards G+0.693
- Probing Dark Matter-Electron Scattering with the Central Molecular Zone
BibTeX
@misc{wilkinson2026salvage,
title = {{SALVAGE II: no systematic molecular gas depletion in the central 2 kpc of AGN hosts}},
author = {Scott Wilkinson and Chiara Circosta and Toby Brown and Sara L. Ellison and Shoshannah Byrne-Mamahit and Almudena Alonso-Herrero and Santiago Garcia-Burillo and Federico Esposito},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.25371},
eprint = {2609.25371},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.25371},
}
RIS
TY - UNPB
TI - SALVAGE II: no systematic molecular gas depletion in the central 2 kpc of AGN hosts
AU - Scott Wilkinson
AU - Chiara Circosta
AU - Toby Brown
AU - Sara L. Ellison
AU - Shoshannah Byrne-Mamahit
AU - Almudena Alonso-Herrero
AU - Santiago Garcia-Burillo
AU - Federico Esposito
PY - 2026
DA - 2026/09/21
PB - arXiv
DO - 10.48550/arxiv.2609.25371
UR - https://arxiv.org/abs/2609.25371
AB - In cosmological simulations, active galactic nuclei (AGN) feedback is found to be necessary for the shutdown of galaxy-wide star-formation by heating and/or removing molecular gas. However, at low-redshift, there is little evidence of systematic large-scale gas depletion. Some recent observations have found molecular gas depletion in AGN hosts, but limited to the central regions of galaxies. In this work, we use the SDSS-ALMA Legacy-Value Archival Gas Exploration (SALVAGE) dataset, which provides molecular gas and stellar mass measurements from the inner (r < 0.5-2 kpc) and outer region of the galaxy. Using AGN diagnostics from optical emission lines, mid-IR colour, and X-ray luminosity, we identify 70 AGN at z < 0.07 and inspect their central molecular gas reservoirs with a suite of metrics compared to non-AGN controls. In agreement with global studies of low-z AGN hosts, we find that, compared to matched non-AGN, the central regions of AGN have equal molecular gas fractions and enhanced molecular gas surface densities. For the first time, we explore the central gas reservoirs of AGN identified with different selection criteria and find two optical AGN classes that show a tentative 1.5σ and 1.8σ signal of central molecular gas depletion. However, the AGN with central gas depletion do not occupy any specific region of the parameter space, such as AGN luminosity, that can provide a physical explanation for the depletion. If AGN are responsible for large-scale gas removal, the lack of systematic gas depletion in SALVAGE AGN sets an upper limit on the physical scale of the gas removal while the AGN remains observable.
ER -