A power spectrum analysis of the angular scale of Galactic neutral hydrogen emission towards l = 140 , b = 0

Angular power spectra are derived from the DRAO Galactic Plane Survey for H I emission with velocities between ≈0 and ≈ –95 km s–1 with respect to the Local Standard of Rest. The angular scales range from ≈ 1° to ≈0.1° for the brightest emission in the Perseus arm. Generally the spectra are well fitted by a power-law dependence on radius in the uv-plane, with an index between ≈– 2.2 and ≈–3.0. The more distant H I, which corresponds to large physical scales, tends to have a more negative index than the nearer H I. There is no preferred angular scale apparent at any velocity. These results provide a concise statistical description of H I in the outer Galaxy.