The Dense Interstellar Medium in Dwarf Galaxies

AST 98-03065 James M.杰克逊 杰克逊博士和巴尼亚博士正在观察属于银河系本星系群的三个星系：大麦哲伦云（LMC），小麦哲伦云（SMC）和IC 10。 本星系群大约有30个成员星系，银河系和仙女座星系是本星系群中两个较大的成员星系。 其他星系是矮椭圆星系或不规则星系。 大麦哲伦星系和小麦哲伦星系是两个不规则的星系，显示出过去与银河系相互作用的证据。 IC 10星系是一个邻近的矮椭圆星系。 LMC和SMC是南半球天体。 IC 10是一个北方星系。 像这三个矮星系形成了与早期星系中发现的条件有用的类似物。 早期星系的金属丰度很低，也有星星形成区，就像矮星一样。 矮星系的优势在于它们相对较近。 因此，PI可以利用这些来自附近矮星系的观测数据来建立一个用于原始星星形成（PSF）研究的模板。 稠密的分子气体是恒星形成的关键元素。 这些气体为新星星的形成提供了原燃料。 这种稠密的气体在过去很难被观测到，只有最亮的分子谱线被测量到。 这些线在电磁波谱的亚毫米和毫米部分被发现。 现在，随着毫米和亚毫米波长接收器和望远镜的改进，PI观察并绘制了几条新的分子发射线，特别是中J CO线和C I线。 新的南极亚毫米波望远镜和远程天文台（AST/RO）是研究电磁频谱亚毫米波部分的理想选择。 该项目是观测麦哲伦云的天文台重点项目的一部分。PI的也使用詹姆斯克拉克麦克斯韦望远镜（JCMT）的IC 10，这是一个北方半球星系。 此外，他们还使用红外卫星观测站（ISO）的数据来完成一系列诊断。 ***

AST 98-03065 James M. Jackson Dr. Jackson and Dr. Bania are observing three galaxies that belong to the Milky Way Local Group of galaxies: the Large Magellanic Cloud (LMC), the Small Magellanic Cloud (SMC), and IC 10. The Local Group has about 30 member galaxies in it. The Milky Way and the Andromeda Galaxy are the two large galaxy members of the Local Group. The other galaxies are dwarf ellipticals or irregulars. The LMC and the SMC are two irregular galaxies that show evidence of a past interaction with the Milky Way. The galaxy IC 10 is a nearby dwarf elliptical galaxy. The LMC and SMC are southern hemisphere objects. IC 10 is a northern hemisphere galaxy. Dwarf galaxies such as these three form useful analogs to the conditions found in early galaxies. Early galaxies have low metallicities as well as star forming regions, just as the dwarfs do. Dwarf galaxies have the advantage that many are relatively close. The PI's can, therefore, use these observations from nearby dwarf galaxies to build a template to use for primordial star formation (PSF) studies. Dense molecular gas is a crucial element in the formation of stars. This gas provides the raw fuel for new star formation. Such dense gas has been difficult to observe in the past and only the brightest of the molecular lines had been measured. These lines are found in the submillimeter and millimeter part of the electromagnetic spectrum. Now with improved millimeter and submillimeter wavelength receivers and telescopes the PI's observe and map several new molecular emission lines, especially the mid J CO lines and the C I lines. The new Antarctic Submillimeter Telescope and Remote Observatory (AST/RO) is ideal for studies in the submillimeter part of the electromagnetic spectrum. This project is part of an Observatory Key Project to survey the Magellanic Clouds. The PI's also use the James Clark Maxwell Telescope (JCMT) for IC 10 which is a northern hemisphere galaxy. In addition, they use data from the Infrared Satellite Observatory (ISO) to complete a set of diagnostics. ***