2026ApJ..1000L..12Q

We investigate large-scale gas kinematics in the multiphase circumgalactic medium (CGM) using the observed correlation between line width (Doppler b parameter) and column density (N) for H I and O VI absorbers. Leveraging extensive public galaxy survey data at z ≲ 0.1, we construct a new galaxy sample based on the availability of background quasi-stellar objects with far-ultraviolet spectra from the Far Ultraviolet Spectroscopic Explorer (FUSE). By combining this FUSE galaxy sample with literature collections, we find that H I absorbers exhibit a clear inverse correlation between Doppler width and column density over nearly 5 orders of magnitude in N_HI, from N_HI ≈ 10¹³ cm^–2 to N_HI ≈ 10¹⁸ cm^–2, while O VI absorption follows a positive correlation across N_OVI ≈ 3 × 10¹³-10¹⁵ cm^–2. We develop a model framework to interpret these contrasting trends and show that H I absorbers are best described as systems of approximately constant total column density (N_H), whereas O VI traces regions of roughly constant spatial density (n_H and n_O VI_). Under the latter scenario, the observed b_O VI_-N_O VI_ relation maps directly to a velocity-size relation consistent with a Kolmogorov-like turbulent spectrum. Together, these findings reveal a coherent physical picture in which H I and O VI trace a continuous turbulent cascade spanning more than 5 orders of magnitude in spatial scale-from cool, photoionized clumps to warm, highly ionized halo gas-with accretion in the halo outskirts likely driving the turbulent energy injection that sustains the multiphase CGM.