Ultra-stable Wideband Heterodyne Spectrometers: Molecular Lines from Distant Galaxies

【摘要】加州理工学院亚毫米天文台的原型光谱仪对遥远星系外核的测量表明，有一个丰富的科学领域等待着近太赫兹频率的大型地面望远镜的探索。然而，对这种状态的探索将需要具有更好的稳定性和带宽的光谱仪。这笔拨款支持建造一台专用的新仪器，用于观测宽而弱的河外线。SOFIA和FIRST天文台的部分发展将得到利用。这项工作将集中在地面即时仪器的组件上。具体来说，将开发和测试一个3.5 GHz带宽，256通道交叉相关系统，用于超稳定，亚毫米光谱。这将需要对辐射计不稳定性的根源进行调查，并测试新的宽带外差光谱仪结构。

ABSTRACTMeasurements of distant extragalactic nuclei using a prototype spectrometer at the Caltech Submillimeter Observatory have shown that there is a rich field of science awaiting exploration with large ground-based telescopes at near-THz frequencies. Exploration of this regime, however, will require spectrometers with improved stability and bandwidth.This grant supports construction of a dedicated new instrument that will enable observations of wide, weak, extragalactic lines. Some of the development will be leveraged from SOFIA and FIRST observatories. This effort will concentrate on the components for immediate ground-based instrumentation. Specifically, a 3.5 GHz bandwidth, 256 channel cross-correlator system geared to ultra-stable, submillimeter spectroscopy will be developed and tested. This will require an investigation into the origins of radiometer instabilities, and tests of new wideband heterodyne spectrometer architectures.