A comparison of the dynamics of the ionized and neutral gas in NGC 281

Splitting of the forbidden N II line of up to 26 km/sec is found over much of the H II region NGC 281. These observations are correlated with distinct features in the associated neutral clouds mapped by recent radio observations. The intimate relationship of the ionized and neutral gas associated with NGC 281 is discussed, and the possibility of explaining the dynamics by a stellar-wind-driven shell is proposed. It is noted that this investigation is a continuation of a program of observations of the velocity structure in H II regions with the Kottamia 1.9-m telescope. The results are compared with several of the 125 maps of neutral hydrogen (Roger and Pedlar, 1981) in order to study directly the relationship between the ionized and neutral gas. It is shown through the optical results presented that NGC 281 is a typical H II region in that it is observed at the edge of a neutral cloud but unusual in that it is observed through that cloud.