Wide-Field Imaging Spectroscopy in the Submillimeter: SPIFI on AST/RO

这个方案是利用位于南极站的AST/RO望远镜上的SPIFI（南极法布里-珀罗干涉仪）绘制银河系中心和附近星系明亮的CO、CI和NII发射线。SPIFI于2003- 2004年夏季首次部署在AST/RO上，现在（直到2004年冬季）使用当前的5 x 5像素热敏电阻感测（TES）热辐射计阵列观测[NII]和高j CO线。与此同时，康奈尔大学的研究小组正在开发一个16 x 32像素的TES辐射热计阵列，它将在2004- 2005年的南方夏季安装在SPIFI上。因此，在2005年和2006年的冬季，SPIFI将能够使用更大格式的阵列在这些光谱线上对银河系和河外源进行成像。该项目的目标如下：(1)在[CI] 370微米，CO（7-6）和[NII]线上绘制大麦哲伦星云。该矮星系的低金属丰度环境可能与原星系相似，因此研究这些星系中恒星形成与星际介质（ISM）之间的相互作用是理解早期宇宙恒星形成过程的关键。(2)利用[CI]， CO（7-6）和[NII] 205微米线的第一个全采样图表征了邻近星系中ISM的物理条件。这些数据是独一无二的——在能量上很重要的转换中的大规模空间和速度信息——将是理解密度波、条形势和星系范围内恒星形成之间关系的关键。(3)对银河系在[CI] 370微米、CO(7-6) 372微米和[NII] 205微米线内的1.5 x 5.0度区域（108,000光谱/图）以及在高J CO线内的较小区域进行成像，从而表征了“中央分子区”（CMZ）中分子、光解离和电离ISM的激发，并追踪了气体动力学。与SPIFI相比，“最先进的”外差系统需要大约300倍的时间才能在相同尺寸的地图上达到相同的灵敏度（SPIFI的~1天观测转化为~1年的外差观测）。研究结果将及时发表在科学期刊上，大型地图将在数据验证后的一年内发布。学生（本科生和研究生）和博士后对提案中提出的研究至关重要。在此过程中，他们设计和开发了SPIFI的许多设备，并学习如何使用科学和工程软件包，包括IDL，机械桌面，Adobe Photoshop和Zeemax。三名康奈尔大学的研究生和两名博士后已经在SPIFI工作。

This proposal is to map the Milky Way Galactic Center and nearby galaxies in their bright CO, CI, and NII emission lines using the SPIFI (South Pole Fabry-Perot Interferometer) on the AST/RO telescope at the South Pole Station. SPIFI was deployed for the first time on AST/RO during the 2003-04 summer season and is now observing (through winter of 2004) the [NII] and high-J CO lines using the current 5 x 5 pixel array of thermister-sensed (TES) bolometers. Meanwhile, the Cornell group is developing a 16 x 32 pixel array of TES bolometers, which will be installed on SPIFI during the austral summer of 2004-05. Thus, during the 2005 and 2006 winters, SPIFI will be able to image Galactic and extragalactic sources in these spectral lines using the larger format array. The project's objectives are the following: (1) To map the Large Magellanic Cloud in the [CI] 370 microns, CO(7-6), and [NII] lines. The low metalicity environment in this dwarf galaxy may mimic that of protogalaxies, so that investigating the interaction between star formation and the interstellar medium (ISM) in these galaxies is key to understanding the star formation process in the early Universe. (2) Characterize the physical conditions of the ISM in nearby galaxies with the first fully sampled maps in the [CI], CO(7-6), and [NII] 205microns lines. These data are unique -- large-scale spatial and velocity information in transitions that are energetically important -- and will be key to understanding the relationships between density waves, bar potentials, and galaxy-wide star formation. (3) Image the inner 1.5 x 5.0 degrees regions of the Milky Way Galaxy (108,000 spectra/map) in the [CI] 370 microns, CO(7-6) 372 microns, and [NII] 205 microns lines, and smaller regions in the high J CO lines, thereby characterizing the excitation of the molecular, photodissociated, and ionized ISM in the "Central Molecular Zone" (CMZ) and tracing the gas dynamics. Comparing to SPIFI, the "state-of-the-art" heterodyne systems would take ~300 times longer (~1 day of SPIFI observations translates to ~1 year of heterodyne observations) to reach the same sensitivity over the same size maps. The results will be promptly published in scientific journals, and the large maps will be released within a year of data verification. Students (both undergraduate, and graduate), and post-docs are vitally important to the research presented in the proposal. Along the way, they design and develop many pieces of SPIFI's equipment, and learn how to use scientific and engineering software packages, including IDL, Mechanical Desktop, Adobe Photoshop, and Zeemax. Three Cornell graduate students and two post-docs have already worked on SPIFI.