Improved Estimates of Galactic H II Region Emission Measures and Filling Factors: Low-Frequency VLA Observations near Sharpless 53

In this paper, 90 cm continuum observations with the VLA of five distant H II regions near the Sharpless 53 complex are used to obtain improved estimates of their physical properties. It is shown that continuum observations at long wavelengths where the H II regions are optically thick can he used, together with T(e) values and flux density measurements obtained at shorter wavelengths where the regions are optically thin, to determine accurate emission measures. It is also shown that such observation scan be used to constrain the filling factors of the ionized gas in the H II regions.