Imaging the Universe in the Far-Infrared

我最近回到加拿大，担任加拿大实验天体物理学研究主席（CRC），以建立一个试验台，探索与远红外（FIR）波长的空间/光谱干涉测量相关的挑战。这被广泛认为是导致FIR成像光谱下一个重大进展的技术。宇宙发射的能量的一半以上出现在相对未开发的FIR光谱区域，其中大部分是不透明的，因此需要空间仪器。欧洲航天局的普朗克和赫歇尔望远镜最近在FIR中提供了第一个不受约束的宇宙视图。他们重新定义了当前的天体物理学，包括银河系和星系外的来源，以尽可能遥远的光子。赫歇尔望远镜的主镜直径为3.5m，它也突出了“FIR间隙”，即与光谱两侧相比，FIR的角分辨率和灵敏度明显较差。许多赫歇尔的发现正在等待提高空间分辨率的后续观测，以解决这个宇宙新窗口中提出的问题。天文学长期计划已经确定了冷却孔径和干涉测量作为FIR路线图的两个优先事项。由日本主导的宇宙和天体物理学空间红外望远镜（SPICA）是下一代赫歇尔望远镜。SPICA的主动冷却主镜与赫歇尔望远镜的大小相似，并且配备了更灵敏的探测器，预计其灵敏度将超过赫歇尔望远镜100倍。因此，SPICA将具有更高的制图速度和天空覆盖范围，但空间分辨率与赫歇尔相似。赫歇尔在积分时间的几秒内获得了混淆有限光度观测。尽管SPICA的灵敏度将允许光谱辨别部分规避空间源混淆，但我们正在接近单碟FIR能力的基本极限。需要将FIR改进到更好的空间分辨率，以降低混淆限制，并允许实现其他进步的全部潜力。为了克服这一基本的FIR障碍，必须用干涉技术取代传统的成像技术，就像阿塔卡马大型毫米阵列和平方公里阵列等干涉仪正在取代其他频率的单碟天文台一样。虽然我的研究重点是基于实验室的FIR干涉测量测试平台的开发，但它有助于FIR路线图的许多方面，包括利用当前的结果和设施，以及与未来的实验、设施和观测站的合作。我的研究项目是与莱斯布里奇大学（UL）天文仪器小组（AIG）合作进行的。在大卫•内勒（David Naylor）的领导下，AIG提供了一个世界级的环境，拥有超过500万美元的设备，并在过去30年里建立了国际声誉。FIR干涉测量焦点为AIG开辟了一条新的研究途径，并代表了UL在其战略计划的关键支柱之一中建立国际认可的重大投资。我的研究提供了一个底层的机会，成为下一代地面和天基FIR天文学的关键合作伙伴，以及优秀的高素质人才（HQP）培训机会。这项工作在加拿大乃至全世界都是独一无二的，它补充了现有的本地和国际研究网络，并将加强现有的和预期的未来国际合作。我的研究将为许多学生提供HQP培训，通过结合动手仪器，技术，技术和数据处理的发展，以及参与国际合作的广阔前景。

I have recently returned to Canada as a Canada Research Chair (CRC) in experimental astrophysics to establish a testbed for exploring the challenges associated with spatial/spectral interferometry at Far-Infrared (FIR) wavelengths. This is widely regarded as the technology that will lead to the next major advance in FIR imaging spectroscopy. Over half of the energy emitted by the Universe appears in the relatively unexplored FIR spectral region, most of which is opaque from ground-based sites necessitating space-borne instrumentation. The European Space Agency Planck and Herschel telescopes have recently provided the first unfettered views of the universe in the FIR. They have redefined current astrophysics including galactic and extragalactic sources, to the most distant photons possible. Herschel, with its 3.5m diameter primary mirror, has also highlighted the "FIR gap", i.e. the dramatically poorer angular resolution and sensitivity in the FIR compared with either side of this spectrum. Many Herschel discoveries are waiting on enhanced spatial resolution follow-up observations to address the questions raised in this new window on the Universe. The astronomy long range plan has identified cooled apertures and interferometry as two FIR roadmap priorities. The Japanese-led Space Infrared Telescope for Cosmology and Astrophysics (SPICA) is the next-generation Herschel. With an actively cooled primary mirror similar in size to Herschel and more sensitive detectors, SPICA is expected to outperform Herschel in sensitivity by a factor of 100. Thus, SPICA will have greater mapping speed and sky coverage, but at similar spatial resolution to Herschel. Confusion limited photometric observations are obtained by Herschel in seconds of integration time. Even though SPICA's sensitivity will allow spectroscopic discrimination to partially circumvent spatial source confusion, we are approaching a fundamental limit in single-dish FIR capabilities. FIR improvements to much better spatial resolution are needed to lower the confusion limit and allow the full potential of other advances to be realized. Traditional imaging must be replaced by interferometric techniques to overcome this fundamental FIR barrier, much like interferometers such as the Atacama large millimetre array and square kilometre array are replacing single-dish observatories at other frequencies. While my research is focused on the development of a lab-based FIR interferometry testbed, it contributes to many aspects of the FIR roadmap including the exploitation of current results and facilities, and collaboration with future experiments, facilities, and observatories. My research program is in partnership with the University of Lethbridge (UL) Astronomical Instrumentation Group (AIG). Led by David Naylor, the AIG provides a world-class environment with equipment in excess of $5M and an international reputation built over the last 30 years. The FIR interferometry focus opens a new research avenue for the AIG, and represents significant UL investment to build on international recognition within one of the key pillars in its strategic plan. My research provides a ground floor opportunity to become a key partner in future-generation ground and space-based FIR astronomy, and excellent highly qualified personnel (HQP) training opportunities. This work is unique within Canada, and the world, complements the existing research network both locally and internationally, and will fortify existing and anticipated international collaborations into the future. My research will provide HQP training to many students through a combination of hands-on instrumentation, technology, technique, and data processing developments with the broad perspective of participation in international collaborations.