H2O masers associated with bright nebulosities in dark clouds.
Abstract
In the reported search for H2O masers, bright nebulosities catalogued by Bernes (1977) were considered. The catalogue lists emission nebulae, reflection nebulae, and H-H objects. The search included also a few Herbig Ae/Be stars, and IR/FIR sources. Approximately 130 bright nebulosities were studied for H2O emission. Eight masers were detected, six of them previously known. It is thought that the reason for this sparse result is partly due to the survey technique. However, H2O masers are clearly not as frequent in dark nebulae as they are near H II regions. The detected masers are of low luminosity and extremely variable. Most of them are associated with IR sources or pre-main-sequence stars. With better sensitivity, all these H2O masers can probably be identified with IR objects.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- June 1981
- Bibcode:
- 1981A&A....99...80S
- Keywords:
-
- Early Stars;
- Infrared Astronomy;
- Interstellar Masers;
- Molecular Clouds;
- Star Distribution;
- Water Masers;
- Astronomical Spectroscopy;
- Atmospheric Attenuation;
- H Ii Regions;
- Infrared Spectra;
- Infrared Spectrometers;
- Nebulae;
- Radial Velocity;
- Traveling Wave Amplifiers;
- Astronomy