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

用加州理工大学亚毫米天文台的原型光谱仪对遥远的河外星系核进行的测量表明，有一个丰富的科学领域等待着用接近太赫兹频率的大型地面望远镜进行探索。然而，探索这一体制将需要具有更高稳定性和带宽的光谱仪。这笔赠款支持建造一台专用的新仪器，使之能够观察到宽广、微弱的银河系外线。索非亚天文台和First天文台将利用一些发展成果。这项工作将集中在立即进行地面测量的部件上。具体地说，将开发和测试一个3.5 GHz带宽、256个通道的交叉相关器系统，以实现超稳定的亚毫米光谱。这将需要调查辐射计不稳定性的来源，并测试新的宽带外差光谱仪架构。

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.