A Comprehensive Active Galactic Nuclei Inventory for the Dwarf-dominated RESOLVE and ECO Surveys: Mass-dependent Active Galactic Nuclei Types and Occupation Fractions

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Abstract
We catalog active galactic nuclei (AGN) in the volume- and mass-limited Resolved Spectroscopy of a Local Volume (RESOLVE) and Environmental Context (ECO) surveys using (i) the BPT plot with standard and alternate demarcations, (ii) the BPT plot and Veilleux– Osterbrock plots (using [O I ] or [S II ]) to find “SF-AGN” with mixed star-forming and AGN classifications, and (iii) mid-IR WISE color selection. Dividing RESOLVE+ECO into dwarf, transitional, and giant galaxies by baryonic mass, we find AGN occupation fractions of 2%–5%, 16%–27%, and 20%–48%, respectively, indicating a steep ∼5× increase across baryonic mass ∼10 9.7 M ⊙ . These percentages are computed relative to all galaxies in each mass division, including those not searchable for AGN, with numerical ranges representing large systematics between crossmatched emission-line measurements from different Sloan Digital Sky Survey (SDSS) catalogs. Stellar-mass divisions yield similar results. Adding (incomplete) archival X-ray/broadline AGN detections, the dwarf AGN occupation fraction reaches 3%–6%. WISE AGN are detected in <1% of galaxies at all masses with optimized WISE photometry. We show that standard WISE catalog photometry yields high rates of both false positives and false negatives. AGN demographics shift with mass due to correlations with gas content, star formation, and group environment, forming a continuum: SF-AGN at the high-SF end, then “Bonus AGN” (defined by alternate literature BPT demarcations), then Composites, and finally Conventional AGN at the low-SF end. Typical (metal-poor, star-forming) dwarfs most often host SF-AGN, whereas typical transitional galaxies most often host Bonus AGN and Composites. We release homogenized SDSS line measurements, reprocessed WISE data, and UV+mid-IR star formation rates for RESOLVE and ECO.
Funding Information
  • National Science Foundation (AST-2007351)
  • National Aeronautics and Space Administration (GO1-22089A)

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