2026ApJ...998..110K

We investigate the ionized gas kinematics of H II regions in the disk of NGC 7331 using integral field unit data collected with the Circumgalactic Hα Spectrograph (CHαS). NGC 7331 is a well-studied nearby galaxy with H II regions resolved by seeing-limited observations, making it ideally suited for this work. The galaxy disk features vigorous star formation, especially in the central ring of starburst activity. We present a catalog of 136 H II regions detected in the SIRTF Nearby Galaxies Survey (SINGS) Hα image. Using this refined catalog, we perform aperture photometry on the SINGS narrowband Hα images of NGC 7331, extracting the Hα luminosity L(Hα) of these regions. We present corresponding measurements of the average line-of-sight ionized gas velocity dispersion σ in these H II regions with CHαS. High-resolution velocity and dispersion maps of the galactic disk are produced from the CHαS spectral imaging, selecting spaxels with high signal to noise in order to measure velocity dispersions as low as 12 km s^–1. Our measurements of the L(Hα), Σ_SFR, and σ in NGC 7331 are consistent with spatially resolved observations of H II regions in large surveys of nearby galaxies. We explore the L(Hα)-σ relationship, identifying turbulent H II regions with nonthermal dispersions likely driven by stellar feedback. The dispersion is correlated with the star formation rate surface density, and using the relation $\sigma \propto \epsilon {{\rm{\Sigma }}}_{{\rm{SFR}}}^{\alpha }$, H II regions in NGC 7331 are best fit by ϵ = 80, α = 0.285.