Visual extinction towards the Omega Nebula (M17) and the ionization of nitrogen in the nebula |
| |
Authors: | Yu. I. Glushkov V. F. Esipov L. N. Kondrat’eva |
| |
Affiliation: | (1) Sternberg Astronomical Institute, Universitetskii pr. 13, Moscow, 119992, Russia;(2) Fesenkov Astrophysical Institute, Academy of Sciences of Kazakhstan, Kamenskoe Plato, Almaty, 480068, Kazakhstan |
| |
Abstract: | We estimate the absolute intensity of the Hα emission line in M17 based on spectroscopic observations with the 70 cm telescope of the Fesenkov Astrophysical Institute and the 1.25 m telescope of the Sternberg Astronomical Institute’s Crimean Laboratory. The visual extinction, A v , is derived for about 250 regions in the nebula via a comparison of the optical (Hα) and radio (21 cm continuum) emissions. The A v values for the eastern, optically bright, part of the nebula are 2–6m. For the western part, which is covered by a dark cloud, the extinction is A v = 7?14.5m. We derived I(Hα)/I([NII] λ6584) ratios and estimated the degree of ionization of nitrogen in the nebula; we find that most nitrogen is in the [NIII] state. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|