INFRARED RECOMBINATION LINES OF HYDROGEN FROM YOUNG OBJECTS IN THE SOUTHERN GALACTIC PLANE

We have observed near infrared recombination lines of hydrogen in twelve young objects in the southern Galactic plane. The sample includes Herbig-Haro objects and IRAS dark cloud point sources from the 1987 catalog of Persson and Campbell. In four of the IRAS sources we have measured two or three infrared lines, and their intensity ratios are consistent with models of optically thick ionized winds. The intrinsic line shapes, which we retrieve from maximum entropy deconvolutions, indicate gas velocities of 100 km s-1 or more as expected from ionized winds. These sources are apparently embedded pre-main-sequence objects with outflows. They include some of the brightest known YSOs.