Overview

HOPS is a survey of selected bands in the 12mm window with the Mopra radiotelescope. HOPS will cover 90 square degrees of the sky, starting from l=300^o and continuing through the Galactic centre (l=0^o) and through to l=30^o. The survey width is 1^o in Galactic latitude (ie. | b | ≤0.5^o), centred on the Galactic plane. The observations are conducted over the summer months, when the telescope is unavailable for 3mm observations, but the conditions are still good enough for 12mm observations. We intend to complete HOPS observations by the end of March, 2010, with approximately 6 weeks of observations each summer, starting in 2008.

The aims of HOPS are:

To provide an untargeted survey of water masers towards the inner Galaxy

This will allow a direct comparison of the occurrence of water and methanol masers (using the results of the Methanol Multibeam Survey). We will be able to determine how much overlap there is between the two masers, which will help us understand the onset and end of the maser phase in the context of star formation. An untargeted survey will also tell us about the relative prevalence of water masers in different astrophysical objects, such as sites of low/high mass star formation or evolved stars.

To map the high density component of the inner Galaxy

Using the (1,1), (2,2) and (3,3) inversion transitions of ammonia, we will not only be able to determine where the high density gas lies, but we can also derive its temperature and column density. This work will focus on identifying new sites of high mass star formation that may not show up as infrared sources.

To search for emission from unusual lines in the Galaxy

We are able to cover 16 bands simultaneously, which allows us to search for emission from many spectral lines. See Survey Specs for more information.

Andrew Walsh. 22nd May, 2009.