Gamma-ray calorimetry of Seyfert winds

Two stacking analyses based on Large Area Telescope (LAT) data have detected GeV emission from local radio-quiet Seyferts. One was selected via an X-ray ultra-fast outflow (UFO) and one is hard-X-ray-bright. Similar luminosities are attributed to different mechanisms: wind-driven shocks and the accretion-disk corona. Fermi We investigated how efficiently Seyfert outflows convert mechanical power into GeV photons, whether the two detections require distinct mechanisms, and how Seyferts compare with low-ionization nuclear emission-line regions (LINERs). We performed no new reduction of -LAT data but homogenized published measurements to 0.1--100 GeV, placed local mechanical accelerators on one L_γ-- Fermi diagram, and expressed η=L_γ/ as a fraction (̊ho) of the fiducial complete-calorimetry efficiency η_ inverting ̊ho for the ambient density required by pp losses. Winds from Seyfert active galactic nuclei (AGNs) have ̊ho=0.020^ +0.018 _ -0.011 for an acceleration efficiency of 0.1, a factor of simeq13.5 below starburst superwinds (̊ho=0.26^ +0.37 _ -0.16 ). The difference exceeds a factor of three with probability 0.95 and is independent of acceleration parameters common to both classes; it is conditional on the wind kinetic powers, collapsing only if every wind sits at its minimum launch radius. The implied densities, sim10 and sim10^2 cm -3 $, are consistency values, as density, shock radius, and speed are degenerate. The two stacking detections agree within a factor of 1.75 in γ-ray output per unit Eddington luminosity, but the 95 percent interval, 0.26--$24, is too wide to distinguish between them. A third stack, of 186 low-luminosity AGNs, extends the comparison 1.5 dex lower, ordered by AGN power. The GeV detectability of a non-jetted AGN is set by the product of mechanical power and calorimetric fraction. LINER outflows lack the power. For the adopted wind energetics, UFO-selected Seyfert winds fall short in calorimetry. Starburst superwinds succeed in both.