Ongoing and Future FIR Instruments

On the ground, the Atacama Large Millimeter/submillimeter Array (ALMA) is located in the Chile s Atacama desert. Its initial configuration is composed of 66 antennas with a possible extension in the future. ALMA is entering operation Cycle 2 in June 2014 (with 6 of its 10 spectral bands) and has already shown enormous potential in exploring the high-spatial resolution FlR-mm wave window in its early test runs. In Cycle 2 thirty four 12-m antennas in the main array (12-m Array), and nine 7-m antennas (7-m Array, for short baselines) and two 12-m antennas (Total 

Power Array or TP Array, for making single-dish maps), which together constitute the Atacama Compact Array will be available. 

Both these facilities shown in Fig. 1.5 will represent a significant improvement in angular resolution in the sub-mm to mm wavelength ranges and in the mid-infrared respectively, but a gap will be left in the important FIR window, wherein the best resolution possible will be 2-3 orders of magnitude worse than the surrounding spectral ranges. 

Study call for exquisite angular resolution of the order of 0.02 arcseconds at 100 (t,m, as well as sufficient sensitivity to allow photon-starved spectroscopy across an arcminute field of view in the 25-400 p,m band. 

An example of this achievable spatial resolution is portrayed in Fig. 1.6 where a comparison with Herschel and Spitzerbeam footprints is made on a simulated JWST deep field. Here the study of single galaxies would be possible beating the current confusion limit. 

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