Balmer Line Photometry of the 30 Doradus Nebula

摘要

The 30 Doradus nebula was scanned at 29 strips of constant declination with a square diaphragm of 30' x 30' using H alpha and H beta interference filters. The absolute flux calibration was obtained from observation of six planetary nebulae. Maps, integrated fluxes, and peak brightness values are given. The ratio between the H alpha and H beta intensities is compared with the theoretical value obtained from recombination theory, to calculate the amount of interstellar reddening. The visual absorption fluctuates rapidly from point to point, but there is a systematic increase from about 0. sup(m)7 to more than 2 sup(m) in the NW to SE direction. Comparing optical with radio data, the mean visual absorption is 1. sup(m)2. (Atomindex citation 10:460133)