Support for observing at the Green Bank 100m Telescope (2)

In a range of wavelengths around 3.5 mm, radio emission from normal star-forming galaxies is expected to be dominated by the free-free mechanism. This free-free emission is usually very weakly constrained by other radio observations since it is swamped by synchrotron radiation at longer wavelengths and dust emission at shorter wavelengths. Mapping the emission of normal galaxies at around 3.5 mm will therefore provide a check of our understanding of physics of radio emission mechanisms and models of normal galaxies. Due to the demanding surface-brightness sensitivity requirements of such observations, they are best done using wide-bandwidth focal plane arrays on large filled-aperture telescopes. We have been awarded the full time request of 15 hours for a pilot project at the Green Bank 100-metre diameter telescope (GBT) to map two nearby galaxies with the MUSTANG bolometer camera operating at 90 GHz. The GBT is by far the largest telescope in the world capable of operating at 90 GHz and the MUSTANG camera is the only general-purpose camera operating at 90 GHz. We request support for travel for one person to the site to carry out these initial observations and train in the remote observing procedures. In-person visits for initial observations is required by the Green Bank procedures. Additionally these observations will be very challenging in terms of absolute calibration requirements, and very dry and clear weather requirements.