Implementation of Tidbinbilla 70-m On-The-Fly mapping and Hydrogen radio recombination line early results

Abstract

On-the-fly mapping of cm-wave spectral lines has been implemented at the the Tidbinbilla 70-m radio antenna. We describe the implementation and data reduction procedure and present new H92$\alpha$ radio recombination line maps towards Orion A and Sagittarius A. Comparison of the Orion~A map to previous observations suggests that the lines arise largely from gas with electron density of 100--200\,cm${}^{-3}$. On-the-fly mapping is very efficient at generating large maps of bright lines (such as radio recombination lines), but will still yield strong efficiency gains for smaller maps of fainter lines, such as the ammonia inversion lines at the 1.3\,cm wavelength.

8 pages, 3 tables, 8 Figures. Accepted for Publication in the Monthly Notices of the Royal Astronomical Society Journal

References in corpus (6)

• MALT90: The Millimetre Astronomy Legacy Team 90 GHz Survey
• The On The Fly Imaging Technique
• Radio Recombination Lines in Galactic HII Regions
• Spectral imaging of the Central Molecular Zone in multiple 7-mm molecular lines
• Understanding hydrogen recombination line observations with ALMA and EVLA
• The Mopra Southern Galactic Plane CO Survey - Data Release 1

Cited by in corpus (3)

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• The Chemistry and Kinematics of Two Molecular Clouds near Sagittarius A*