THUMPER, the Two-Hundred Micron Photometer, will be a novel new instrument for use on the JCMT and other submillimetre telescopes. Under the best atmospheric conditions at Mauna Kea, a transmission window at 200μ m opens, with atmospheric transmission better than 25% during very dry weather. THUMPER will take advantage of these conditions to take FIR high-resolution (7'') observations with sensitivites comparable to that of instruments previously flown on the Kuiper Airborne Observatory. Further, because of the steep rise in flux towards short wavelengths of thermal sources (which includes most sources of interest), THUMPER will be able to achieve the same SNR as the 450μ m array of SCUBA in a similar amount of time, with similar angular resolution, a capability not provided by any other facility. This instrument will provide powerful new data for the study of many differnt types of astronomical sources, ranging from YSOs and pre-stellar cores to evolved stars to nearby galaxies. One of the primary difficulties in studying such sources is the fact that they have temperature and density distributions which vary across the source. The submillimetre measurements of SCUBA are a powerful tool to study these sources, but these observations are not able to differentiate between temperature and density variations across sources because they do not sample the peak of the Planck function. The FIR observations of ISO and other space-based missions are of value for examination of the global spectral energy distribution, but because of the poor angular resolution of such facilities, cannot be used to separate the effects of temperature and density variations. THUMPER will provide the high-resolution measurements which are needed to differentiate between these effects, opening a valuable new window for FIR astronomy.
American Astronomical Society Meeting Abstracts #195
- Pub Date:
- May 2000