Kinematics of the Hourglass region in the Lagoon nebula

The Hourglass region, ionized solely by the star Herschel 36, represents the brightest part of the Lagoon nebula. In this paper, we present new kinematic observations of the region in [N II] 6583 Angstrom emission line using an imaging Fabry-Perot. spectrometer in the spectrographic mode. We find both asymmetric and symmetric fine profiles with large linewidths of 22-40 km/s towards the regions of the Hourglass and Herschel 36. The H II region of the Hourglass reveals a notable expansion up to -18 km/s with respect to the star. Our kinematic data suggest a particular orientation of the cavities created by the H II region expanding into the parent molecular cloud, Relatively higher velocities of -30 to -50 km/s are observed south of Herschel 36, indicating the presence of low density regions and champagne flow. (C) 1997 American Astronomical Society.