大學聯合ALMA科學創進中心(科創中心)–挑戰、生存、和永續-利用ALMA 探索南天的毫米波與次毫米波輻射源

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Title:	大學聯合ALMA科學創進中心(科創中心)–挑戰、生存、和永續-利用ALMA 探索南天的毫米波與次毫米波輻射源
Other Titles:	Exploring the Southern Sky in Mm- and Sub-Mm Waves with Alma
Authors:	秦一男
Contributors:	淡江大學物理學系
Keywords:	ALMA;Atacama Large Millimeter Array;Magellanic Clouds;The Galactic Center;Starburst Galaxies;NGC4945;millimeter & sub-millimeter Observations
Date:	2011
Issue Date:	2012-05-03 20:12:45 (UTC+8)
Abstract:	在北美洲、歐洲及日本的合作下，ALMA (Atacama Large Millimeter Array)已經進入最後的建造階段，它無疑將成為二十一世紀中最重要的天文儀器之一。這座興建於智利北部Atacama 沙漠中，標高5000 公尺Llona de Chajnantor 高原上的毫米/次毫米波段干涉式陣列天文望遠鏡，將達到前所未有的高靈敏度、高解析度、以及極大的頻率涵蓋。台灣目前透過中研院與日本的合作加入ALMA 而組成東亞團隊，及與NRAO 的合作加入北美團隊；但未來的觀測時間將必須與其他各國競爭。為使台灣不在這樣的跨國性大型計劃中缺席，本計劃以主持人在過去幾年來於南半球觀測的經驗為基礎，希望在未來的三年中 (這涵蓋了ALMA 從完全完工前的早期觀測，到完工後的正式觀測階段)，針對(1) 銀河系中心(Galactic Center)、(2) 大小麥哲倫星系(Large & Small Magellanic Clouds)、(3) 星暴增星系(starburst galaxies, 如 NGC4945)以及其他任何可能的研究對象，除了ALMA 之外，並同時利用現役的南半球毫米與次毫米波望遠鏡：澳洲ATNF 的Mopra 望遠鏡與ATCA 干涉儀及MPIfR 興建於Chajnantor 的APEX，在此一波段完成有系統的全面性普查。其中ATCA 已升級完成，成為南半球在ALMA 完工前唯一的一座毫米波干涉儀，可提供以往在南天觀測時所無法達到的高解析度；而APEX 更是針對頻率90 GHz 至1 THz 以上的次毫米波波段而興建。我們可以預期的是，藉由這些準備工作所得到的觀測結果不但對了解這些南天天體內的物理與化學環境有立即的收穫，更能搭配接下來的ALMA 觀測。如此一來，我們除了可以藉由提出具有競爭力的研究課題，做為進一步爭取ALMA 觀測時間的後盾，更能結合兩者的研究成果，得到更完整的資訊。尤其是ALMA 預計將於2012 年開始正式運轉，而在此之前預計於2011 年底開始利用部份天線與時間做前期的測試性觀測，因此，在此之前乃至於運轉的初期階段我們都必須作好準備。我們希望藉由本計畫，可以將現有研究由初期的探路，帶入ALMA 的早期觀測階段，再進入正式觀測階段。在天文觀測儀器趨向大型化及國際化之際，這是資源有限的國家確保不被排除在「大型天文觀測儀器俱樂部」大門外的可行之道。 ALMA (Atacama Large Millimeter Array), which is jointly founded by North America and Europe, is up to now the most ambitious radio astronomy project ever undertaken by the world. This project has been even extended after Japan decided to join it. At least 50 12-m antennas will be constructed at an altitude of 5000 m, on top of Llano de Chajnantor in the Atacama Desert of northern Chile. Japan joins this project by contributing the Atacama Compact Array (ACA, containing 12  7-m and 4  12-m antennas). ALMA will be equipped with mm and sub-mm receivers which cover the frequencies from 90 GHz up to 1 THz. Once it is finished, ALMA will be one of the most important observational facilities in astronomy with its extremely high sensitivity, high angular resolution, and wide frequency coverage. It is obvious that astronomers in Taiwan can remain competitive only if we have access to this world-class instrument. Academia Sinica’s Institute of Astronomy & Astrophysics (ASIAA) already join Japan (represented by National Astronomical Observatory of Japan; NAOJ) to form the East-Asia team. The decision has also been made to join North America team through NRAO. There is no doubt that ALMA will open a new era for observational astronomy. After many years of observing experience with telescopes in the southern hemisphere, we propose to explore the southern sky in mm and sub-mm wavelength. This will include mainly, but not exclusively, the following three objectives: (1) the Galactic Center, (2) Large & Small Magellanic Clouds, and (3) starburst galaxies, such as NGC4945. We intend to use the 22-m Mopra telescope, the ATCA (Australia Telescope Compact Array) of ATNF (Australia Telescope National Facility) and APEX (Atacama Pathfinder EXperiment) built at Chajnantor by the MPIfR (Max-Planck-Insitut für Radioastronomie) to investigate these interesting southern sky targets. The ATCA has been upgraded to the millimeter range and it is the only southern millimeter interferometer before ALMA era. It will provide a high angular resolution that has never been achieved in the southern sky. APEX will be operating mainly in the sub-millimeter wavelength range, with some receivers for frequency as high as 2 THz. With these new observation tools we expect to obtain high resolution imaging for both molecular spectroscopy and bolometer measurements of the dust emission. All these results will not only improve our understanding of physical and chemical processes taken place in the interstellar medium, but also help us to get prepared for ALMA. We hope to get the ALMA observing time by well-prepared and competitive proposals. Since ALMA should start its operation in 2012 and there will be early science observation before it, with the first call-for-proposal in spring of 2011. It is not too early now to be prepared for this new era of observation. We intend to start this project as an ALMA “pathfinder”, followed with ALMA regular observation through early science observation. For countries with limited resources, such as Taiwan, this provides another possibility to be involved in a large international project.
Appears in Collections:	[Graduate Institute & Department of Physics] Research Paper

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