The molecular surroundings of W 3(OH).
Abstract
We have observed the molecular cloud surrounding the ultra-compact HII region W3(OH) in C(18)O(1-0), HCO(+)(1-0), and CH3CN(5-4) using the three element interferometer on the Plateau de Bure. We also present H41-alpha and H59-gamma measurements of the ionized gas. We find that our methyl cyanide image consists of two compact sources. Of these, one essentially coincides with the cluster of water maser to the east of the continuum source and shows evidence for an east-west velocity gradient similar to that observed in water maser proper motions. The other compact methyl cyanide region appears to be identified with the high density molecular clump which harbors the OH masers. We estimate temperatures of order 100 K from our methyl cyanide data for both compact regions. We also find a compact continuum source at 110 GHz towards the CH3CN peak associated with the water maser cluster. We estimate that the source has a column density of 3 x 1025/sq cm and a mass of 30 solar mass but with considerable uncertainty. The C(18O and HCO(+) maps towards W3(OH) show evidence for much more extended structures. We observe absorption in HCO(+) towards the continuum source at a velocity of -45 km/s which is similar to the value found for species such as NH3. Our C(18)O results show that, as well as the compact clump associated with the water masers, there is a more extended region of roughly 0.05 parsec in size and of mass 60 solar mass surrounding the water maser complex.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- January 1994
- Bibcode:
- 1994A&A...281..505W
- Keywords:
-
- Acetonitrile;
- Carbon Monoxide;
- Formyl Ions;
- H Ii Regions;
- Interstellar Matter;
- Molecular Clouds;
- Radio Astronomy;
- Water Masers;
- Absorption Spectra;
- Astronomical Interferometry;
- Interstellar Masers;
- Ionized Gases;
- Astronomy