Atmospheric site testing in Antarctica and observations with submillimetre and millimetre telescopes

Abstract

This dissertation covers, through seven peer-reviewed publications, a number of observations conducted in two different continents, Antarctica and Australia, spanning from the near-infrared to submillimeter and millimeter wavelengths. The work begins in 2001 with a fundamental contribution to the development of SUMMIT, a sky-brightness monitoring instrument operating at 350 μm. This rugged, low power and low maintenance instrument was designed for astronomical site testing and allowed the measurement of atmospheric precipitable water vapour at very dry sites. It was successfully operating at two locations in Antarctica—South Pole and Dome C—making the first measurements of submillimeter sky opacity at the latter one, and demonstrating the site’s outstanding potential for submillimeter astronomy. Improvements and corrections to the skydip observing strategy and to the data reduction algorithms are described. NISM (Near-Infrared Sky Monitor) is an instrument operated with the same observing strategy as SUMMIT—skydips—but in the Kdark window at 2.4 μm. The instrument was installed at the South Pole Station in 2001, and showed good performance in the subsequent winter, confirming that the sky brightness at the site is more than an order of magnitude lower than excellent astronomical sites such as Mauna Kea. The work highlights results from exploiting the submillimeter windows at the South Pole, where I operated without interruption, for the entire year of 2003, SPARO (Submillimeter Polarimeter for Antarctic Remote Observations) a 9-pixel, 450 μm polarimeter installed at the focal plane of Viper, a 2 m submillimeter telescope. Most of the winter was dedicated to measure the magnetic fields in four Giant Molecular Clouds (GMCs). These observations demonstrated that in these regions the magnetic field direction was preserved through the GMC formation process, and that the magnetic energy density was comparable to the turbulent energy density, imposing important constraints on GMC evolution models. The work concludes with results from several observation campaigns from 2004 at the Mopra millimetre telescope, including mapping of 13CO, measurements of glycine and propylene oxides in different GMCs, and a survey of 83 methanol masers in massive star-forming regions.