An Analysis of AGN Feedback in the Compact Galaxy Group Stephan's Quintet

Maura Kathleen Shea, D. Michael Crenshaw, Travis C. Fischer, Mitchell Revalski, Julia Falcone, Beena Meena, Zo Chapman, Jacob Tutterow, Madeline Davis, Kesha Patel

First listed 2026-01-21 | Last updated 2026-01-21

Abstract

Compact galaxy groups are ideal laboratories for studying the effects of interactions between AGN and multiple nearby galaxies. Recent JWST observations of the nearby compact group Stephan's Quintet highlight tidal flows between the interacting galaxies as well as outflows from the active galaxy NGC 7319. To study the kinematics on a large scale throughout the group, we obtained spatially-resolved long-slit spectra of Stephan's Quintet at multiple slit positions with Apache Point Observatory's Kitt Peak Ohio State Multi-Object Spectrograph. We fit multiple Gaussians to the H$α$ $λ$6563 Å and [N II] $λλ$6548, 6583 Å emission lines to isolate the different kinematic components. We used the kinematics to develop the first biconical outflow model of the narrow-line region of NGC 7319. Using a combination of galactic rotation models, biconical outflow models, and kinematic maps of the ionized gas, we disentangled the outflows, rotation, and tidal flows in the group. We found outflow radial velocities up to 550 km s$^{-1}$ peaking at 2.6 kpc from the central supermassive black hole, and a transition from AGN-powered outflows to gravitationally-powered tidal flows at a projected distance between 2.4 -- 6.3 kpc. We performed a line ratio analysis and determined the gas shows Seyfert-like ionization out to 6.3 kpc (projected), which supports our finding that gas outside this radius is predominantly powered by tidal flows. Our separation of kinematic components in Stephan's Quintet will enable future studies of the physical conditions and dynamical forces in the ionized gas to better quantify the feeding and feedback processes of AGN in compact groups.

Short digest

Spatially resolved long-slit spectroscopy across Stephan’s Quintet, with multi-Gaussian decomposition of Hα+[N II], is used to untangle ionized-gas kinematics across the group. The authors build the first biconical outflow model for NGC 7319’s NLR, finding radial velocities up to 550 km s−1 peaking at 2.6 kpc. Combining bicone, rotation, and group-scale maps, they locate a transition from AGN-powered outflows to gravitationally driven tidal flows at projected 2.4–6.3 kpc, with Seyfert-like ionization out to 6.3 kpc. This clean separation of components clarifies how AGN feedback and tidal dynamics co-exist in a dense compact group.

Key figures to inspect

• Slit layout over a JWST/NIRCam+MIRI image of Stephan’s Quintet: verify where the long slits cross NGC 7319, the NGC 7319–7318B bridge, and the shock ridge; read off the projected radii that bracket the 2.4–6.3 kpc transition zone.
• Example Hα+[N II] line-profile fits along the slit: inspect how multiple Gaussian components isolate outflow, rotation, and tidal streams; note asymmetries and component separations near the nucleus vs. in the bridge.
• Position–velocity diagrams with the adopted biconical outflow model overplotted: check the maximum radial velocity (~550 km s−1), the velocity peak at ~2.6 kpc, and constraints on opening angle and inclination.
• Radial or 2D maps of line ratios (e.g., [N II]/Hα or BPT classifications): confirm Seyfert-like ionization persisting to ~6.3 kpc and where tidal/shock-dominated excitation takes over beyond that radius.
• Kinematic maps or model–data residuals separating rotation from tidal flows: look for regions where non-circular motions dominate, especially along the NGC 7319–7318B tidal bridge.