Yu.N. Efremov, V.L. Afanasiev, O.V. Egorov. Ionized Gas Characteristics in the Cavities of the Gas and Dust Disc of the Spiral Galaxy NGC 6946
Submitted on: Aug 27, 2012, 22:24:53
Natural Sciences / Astronomy / Cosmology
Description: The parameters of the ionized gas in NGC 6946 (in the [NII]6548,6583, H-alpha and [SII]6717,6731 lines) are investigated with the SAO RAS BTA telescope along three positions of the long slit of the SCORPIO focal reducer, passing through a number of large and small cavities of the gaseous disc of the galaxy. Most of these cavities correspond exactly to the cavities in warm dust. We found that everywhere in the direction of NGC 6946 the lines of ionized gas are decomposed into two Gaussians, one of which shows almost constant [SII]/H-alpha and [NII]/H-alpha ratios, as well as an almost constant radial velocity within the measurement errors (about -35 - -50 km/s). This component is in fact the foreground radiation from the diffuse ionized gas of our Galaxy; a similar component is also present in the emission of neutral hydrogen. The analysis of the component of ionized gas, occurring in NGC 6946, has revealed that it shows signs of shock excitation in the cavities of the gaseous disc of the galaxy.
The Library of Congress (USA) reference page : http://lccn.loc.gov/cn2013300046.
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