Recombination Lines 158a and 198ß in Nine Southern Nebulae

Abstract

Recombination lines H 158", He 158", and H 198,8 (near ,\ 18 em) have been observed in the HI! regions Orion Nebula, RCW 38 and 49, "I Carinae I, RCW 57, PKS1617-5OI in Norma, NGC6334 and 63571, and Omega Nebula. Physical parameters such as ratio of line to continuum temperatures TdT c, line halfwidths, median radial velocities, and intensity ratios 1(198,8)/1(158,,) and 1(He)/1(H) are given. A lack of agreement in the measured radial velocities of the H 198,8 and H 158" lines in three nebulae is discussed.