MODELING THE STRUCTURE OF H-1 IN THE GALACTIC DISK

For comparison with a detailed H I survey, we calculated models for the H I intensity distribution, T(B)(l, b, v), for a 18-degrees x 12-degrees region in the disk of the Galaxy toward l = 205-degrees. In one class of models, neutral hydrogen is in the form of clouds, while in the other class of models it is a continuous medium with holes whose sizes are typical of supernova remnants and superbubbles. The cloud models are a poor representation of the data in that the amplitude fluctuations are dissimilar and the continuity of the H I observations is not reproduced. A continuous H I medium with holes provides a much better match to the data, and the best-fit models suggest that the filling factor for the H I is 20%-50%.