The H-alpha velocity field of the Omega nebula (M 17)

Abstract

view Abstract Citations (25) References (59) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The H alpha Velocity Field of the Omega Nebula (M17) Joncas, G. ; Roy, J. -R. Abstract Using a Fabry-Perot camera, 9054 H-alpha radial velocities were measured across the H II region M 17. The mean v(LSR) = 18.6 + or - 0.1 km/s, which is 1.4 km/s blueshifted with respect to the mean velocity of the associated molecular cloud M 17 SW. The dispersion of the velocity histogram is slightly skewed to the blue. A gradient in radial velocity is observed from west to east, with the most blueshifted velocities appearing closest to the molecular cloud. The velocity field can be explained as a flow of ionized gas approximatively in the plane of the sky. There is a relation between random velocity and size, with velocity fluctuations increasing as some power of size; the power index depends on the sampling method of the velocity field. An interpretation of the relation is suggested in terms of turbulence, and a brief discussion of mechanisms for turbulent kinetic energy input is presented. Publication: The Astrophysical Journal Pub Date: August 1986 DOI: 10.1086/164450 Bibcode: 1986ApJ...307..649J Keywords: H Alpha Line; Molecular Clouds; Nebulae; Radial Velocity; Velocity Distribution; Astronomical Maps; Gas Dynamics; H Ii Regions; Histograms; Ionized Gases; Astrophysics; NEBULAE: INDIVIDUAL MESSIER NUMBER: M17; RADIAL VELOCITIES full text sources ADS | data products SIMBAD (1)