Stark broadening and radio recombination lines in NGC 7027.
Abstract
The observed upper limit for the ratio T /T0 of central H 109cc line to continuum brightness temperatures in NGC 7027 (Terzian and Balick, 1969) is shown to be consistent with an electron density Ne> 10 cm-8. The lower limit of 10 cm-8 for Ne is smaller by a factor 10 than that found by Goldberg (1970), who did not consider Stark broadening. Further, an emission measure considerably larger than the value derived by high frequency flux measurements is not found necessary to account for the upper limit for TL/To. Key words: Stark broadening - radio recombination lines - H II regions
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- January 1971
- Bibcode:
- 1971A&A....10..159H