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Observations of the 18.3-GHz Transition of C3H2 towards Sgr B2
Published online by Cambridge University Press: 25 April 2016
Abstract
We have mapped the molecular clouds of Sgr B2 in the 110 → 101 ortho-transition of C3H2 at 18.3 GHz, using the 70-m NASA telescope at Tidbinbilla (beamwidth 55 arcsec). Three clouds show absorption against the Sgr B2 continuum emission at radial velocities of 50, 65 and 80 km s−1. The 65-km s−1 cloud covers most of the observed area (4 × 6 arcmin in right ascension and declination), has a peak optical depth of 2.7 and a corresponding C3H2 column density of 7.6 × 1015 cm−2. The C3H2 fractional abundance relative to H2 is 1.5 × 10−9. The 80-km s−1 cloud, located north of the Sgr B2 continuum peak, has a peak optical depth of 0.9 and a C3H2 column density of 1.9 × 1015 cm−2. The 50-km s−1 cloud is centred 2 arcmin south of the continuum peak; here the minimum optical depth of 0.5 yields a column density of 5.3 × 1014cm−2.
- Type
- Galactic and Stellar
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- Copyright © Astronomical Society of Australia 1992