English

Environment and Gas Fraction in Type-2 AGN versus Non-AGN Galaxies

Astrophysics of Galaxies 2026-01-21 v1

Abstract

We investigate the environmental parameters and gas fraction (fgas_{gas}) properties of type~2 AGN and non-AGN galaxies, utilizing a large sample of galaxies from SDSS DR7 with z \le 0.3. We find that the environment affects type~2 AGN and non-AGN galaxies in similar ways and does not impact the strength of AGN-driven outflows. The fgas_{gas} of type~2 AGN and non-AGN host galaxies show no variation between group and isolated environments, suggesting that host galaxy gas content is largely independent of large-scale environment. We find that type~2 AGN host galaxies possess systematically lower fgas_{gas} than their non-AGN counterparts when matched in stellar mass and star formation rate (SFR). This suggests that AGN activity plays a significant role in regulating the molecular gas reservoir and, consequently, the star formation processes within galaxies. We find that Type~2 AGNs exhibiting strong outflows are associated with higher gas fractions, higher star-formation rates, and younger stellar populations than those with weak or no outflows. This may indicate either concurrent star formation in gas-rich systems hosting powerful outflows, or a time delay between AGN activity and its effect on star formation consistent with a delayed AGN feedback scenario.

Keywords

Cite

@article{arxiv.2601.13375,
  title  = {Environment and Gas Fraction in Type-2 AGN versus Non-AGN Galaxies},
  author = {Jyoti Yadav and Jong-Hak Woo and Ashraf Ayubinia},
  journal= {arXiv preprint arXiv:2601.13375},
  year   = {2026}
}

Comments

19 pages, 15 figures, Accepted for publication in APJ