GBT First Light at 3mm
On 26 September 2006, the GBT had first light at 90 GHz with MUSTANG. MUSTANG (the Multiplexed SQUID/TES Array for Ninety Gigahertz, formerly known as the Penn Array) is a 64-pixel TES bolometer array designed to make high-resolution continuum images with the GBT. This is the first use of a multi-pixel imaging array on the telescope, and the highest frequency at which the GBT has collected data. In an engineering run lasting from mid-September through the end of October, data were collected which have enabled the project team to verify basic functionality of the receiver optics, cryogenics, DAQ electronics and software. The GBT proved to be a reliable platform for diagnostic 90 GHz observations, and shows an aperture efficiency (about 10%) which is consistent with what is expected from holographic surface accuracy measurements. Even with such a low aperture efficiency the GBT has a collecting area comparable to the largest millimeter facilities presently in operation. During the upcoming year the MUSTANG team will work to improve the robustness and sensitivity of the receiver, concurrent with a planned campaign of antenna improvements in Green Bank, and aims to return for a system commissioning and early science run in Fall/Winter 2007/2008. NRAO's first millimeter-wave astronomy was done in Green Bank using a bolometer in November of 1962 by Frank Low, this year's Jansky lecturer. MUSTANG was funded by NRAO's Universities Instrumentation Program; the collaboration includes the University of Pennsylvania, NASA Goddard Space Flight Center, NIST, Cardiff University, and NRAO.
FIGURE 1MUSTANG first light map of Saturn at 90 GHz. Saturn's disk at the epoch of observation had a diameter of about 16 arcseconds.
FIGURE 2A GBT 3mm continuum image of the W3main star forming region acquired with MUSTANG. The morphology is similar to that seen in an 8 GHz VLA map of similar resolution, suggesting that at 90 GHz free-free emission still dominates over thermal dust emission.
Modified on Thursday, 09-Nov-2006 13:27:38 EST