As part of the campaign to upgrade and/or replace the aging instruments on the 3.5-m telescope, one of our near-term highest priorities is to acquire a new IR instrument. Although GRIM2 continues to function, several things limit its scientific potential. In particular, it has a 256x256 detector which has very high noise. This gives a small field of view, and makes it difficult to get observations of fainter objects in narrow-band imaging or spectroscopic mode. In addition, the spectroscopic modes either have very low resolution or have rather small slit widths at a bit higher resolution. As a result, we have considered alternative options for improving the IR instrumentation.
The cost of a modern IR instrument is beyond the reach of our budgets, but some form of a cost-sharing partnership is being considered. Several partnership possibilities have been explored, and one of the most promising is RIVMOS (Rapid Infra-red and Visible Multi-Object Spectrograph).
Bruce Woodgate at GSFC is interested in building an IR instrument for use at the 3.5m. He has funding from NGST for a prototype instrument that is supposed to demonstrate the capabilities of a microshutter array, to be potentially used for fully configurable multi-object spectroscopy. The proposed prototype instrument (RIVMOS) has both imaging and spectroscopic capability, using a 1024x1024 InSb detector. He would like to use the instrument at the 3.5m, and in exchange, make it available to the ARC community. Scientifically, one of his motiviations for the instrument is to allow rapid followup, e.g., of gamma ray bursts. As a result, he would eventually like to see this instrument installed on a dedicated port (with associated rotator and guider) on the 3.5m.
Bruce has a long association with APO, and has allowed us to offer the use of his Fabry-Perot camera at the 3.5-m. He is also a renowned instrument builder (STIS, etc.).
At no financial cost to ARC, Bruce is building the camera described in the attachments to the "Phase I" level this year, and we plan to commission the camera and shutter prototype at the 3.5-m. Some possible collaborative early use of the instrument is possible by ARC astronomers.
To fully implement the camera on the telescope as a facility-class instrument, in "Phase II" we would need to dedicate a port to the instrument so that it can be used for fast-attack targets of opportunity. This would involve adding cold foreoptics, a guider and rotator, and control software to enable full remote operation. Various spectroscopic modes are envisaged. An optical layout of RIVMOS is attached to this e-mail, as is a three-page description of the instrument.
We solicit expressions of interest from the ARC user community, and in particular ask you to let us know if you would find this instrument useful for your scientific programs at the 3.5-m. Also, if you have suggestions for technical specifications for the instrument (filter bandpass, sensitivity, image scale, etc.) let us know because there is still time to refine some aspects of the design.
