The Warm Ionized Medium: A High Resolution Northern Hemisphere [SII] Survey and an Emission Measure Atlas

暖电离介质：高分辨率北半球 [SII] 调查和排放测量图集

• 批准号: 0098487
• 负责人: John Simonetti
• 金额: $ 18万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-07-15 至 2006-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0098487&HistoricalAwards=false
• 关键词: Warm; Ionized; Medium; Resolution; Northern

AST 0098487SimonettiThis research probes the structure and physical properties of the warm ionized medium (WIM), a phase of the interstellar medium in which gas is in mostly ionized form at approximate temperatures of 6000 to 10,000 K. The investigators use a sensitive charge-coupled device (CCD) camera system in conjunction with narrowband interference filters to image the distribution of the WIM over the entire northern sky with approximately arcminute resolution. Their previous work included a survey of the WIM in the H-alpha emission line ( 6563A ). In this research they extend previous imaging in the [S II] forbidden-line doublet to cover the northern hemisphere. Hydrogen is excited by photoionization, whereas [S II] is collisionally excited. Thus, the [S II] survey is an ideal complement to their H-alpha survey, making it possible to study the physical properties of the gas. Most importantly, this research will globally address fundamental questions concerning the sources of heat in the WIM by providing the [S II]/H-alpha emission ratio is a large variety of structures. These surveys are presented to the astronomical community (consisting of both researchers and educators ) at the Virginia Tech Spectral-line Survey (VTSS) website (http://www.phys.vt.edu/vtss). The researchers will also produce an H-alpha atlas which combines their VTBB Ha-alpha survey with the WHAM H-alpha survey of Reynolds and collaborators at the University of Wisconsin. These two surveys are ideally complementary. The surveys produced by this research will enable astronomers to study the relationship of the WIM to other phases of the interstellar medium. Through comparison with maps of H I, CO, infrared, and X-ray emission, astronomers will be able to discern how the WIM is distributed in space relative to neutral gas, cold gas, dust, and gas heated to very high temperatures by supernovae and stellar outflows. The angular resolution of the VTSS surveys is well matched to major surveys such as IRAS and ROSAT. This work will involve Virginia Tech undergraduate and graduate students. The researchers are building on previous successes with students trained in conjunction with this research. The camera system is located at a dark site within easy reach of the Virginia Tech campus -- an arrangement that fits the scientific needs of the project, minimizes cost, and enables student involvement. In addition to research uses, the survey images are readily accessible for a wide range of educational uses at the high school and college levels. With this in mind, a simple to use web-based image viewing and processing program is provided for displaying, manipulating, and analyzing the FITS-format images.***

这项研究探索了温电离介质(WIM)的结构和物理性质，温电离介质是星际介质中的一种相，在大约6000到10000 K的温度下，气体主要以电离形式存在。研究人员使用灵敏的电荷耦合器件(CCD)相机系统和窄带干涉滤光片来成像WIM在整个北方天空的分布，分辨率大约为1角分。他们之前的工作包括对H-α发射线(6563A)上的WIM进行调查。在这项研究中，他们扩展了之前在[S二号]禁线双星中的成像，覆盖了北半球。氢是通过光电离激发的，而[S II]是以碰撞激发的。因此，[S二号]的观测是对他们的H-α观测的理想补充，使研究气体的物理性质成为可能。最重要的是，这项研究将通过提供[S II]/H-α发射比是多种结构，在全球范围内解决与WIM中的热源有关的基本问题。这些调查在弗吉尼亚理工大学光谱线调查网站(http://www.phys.vt.edu/vtss).)上向天文学社区(包括研究人员和教育工作者)公布研究人员还将制作一份H-Alpha图谱，将他们的VTBB Ha-Alpha调查与威斯康星大学对雷诺兹及其合作者的WHAM H-Alpha调查相结合。这两项调查具有理想的互补性。这项研究产生的调查将使天文学家能够研究WIM与星际介质的其他阶段的关系。通过与HI、CO、红外和X射线发射图的比较，天文学家将能够辨别WIM相对于中性气体、冷气体、尘埃和被超新星和恒星流出加热到非常高温度的气体在空间中的分布。VTSS调查的角分辨率与IRAS和ROSAT等主要调查相匹配。这项工作将涉及弗吉尼亚理工大学的本科生和研究生。研究人员在以往成功的基础上，与这项研究一起培训了学生。相机系统位于弗吉尼亚理工大学校园附近的黑暗地点--这一安排符合该项目的科学需求，最大限度地减少了成本，并使学生能够参与其中。除了研究用途外，调查图像还可以很容易地用于高中和大学层面的广泛教育用途。考虑到这一点，提供了一个简单易用的基于Web的图像查看和处理程序，用于显示、处理和分析Fits格式的图像。*