POWRE: The Evolution of Elliptical Galaxies: New Clues from Neutral Gas

近年来，人们越来越清楚地认识到，椭圆星系并不像人们曾经认为的那样是死的、没有气体的星系。它们中的许多都含有中性气体，这就提出了一种有趣的可能性，即它们可能正在形成恒星。要完全了解椭圆星系的演化，就必须知道这些中性气体的起源和命运，以及椭圆星系中恒星的形成速度。来自9个椭圆星系的一氧化碳（CO）和氢（HI）发射线的高分辨率图像将由伯克利，伊利诺伊州和马里兰州（BIMA）和欧文斯谷射电天文台（OVRO）毫米波长射电望远镜干涉仪和甚大阵列（VLA）射电望远镜制作。对中性气体分布和运动学数据的分析将为其起源和命运提供重要线索。例如，对数据的分析将显示这些气体是在剧烈合并中获得的，是正在形成恒星，是在为活跃的星系核提供能量，还是正在被其他过程破坏。关于气体分布和运动学的知识也将有助于解释椭圆星系中无线电- fir相关的起源，并将揭示星系环境对其中性气体的影响。这些问题的答案是未知的，因为很少有椭圆星系有关于其分子和原子气体分布的良好数据。这个项目的结果将使具有良好CO和HI发射线图的椭圆星系的数量增加一倍以上。样本星系具有广泛的特性（包括环境、形态、光度）。和核连续源的强度)，这将有助于解开影响椭圆星系的许多过程。该项目的结果将是一个独特的信息综合，将有助于提供一个更好的椭圆星系及其星际介质的全球图景。该项目关于单个椭圆星系中恒星形成速率的结果将与Cotton &amp； London（1998）的统计工作相结合，给出椭圆星系中恒星形成的第一个定量图像。这个项目的结果也将用于完善椭圆星系演化的理论模型。最后，通过展示椭圆星系今天是如何演变的，该项目将有助于绘制高红移和低红移星系之间的联系。本项目由数学和物理科学理事会天文科学司和多学科活动办公室资助

AST-007409YoungIn recent years it has become clear that elliptical galaxies are not dead, gas-free galaxies as they were once thought to be. Many of them contain neutral gas, which raises the interesting possibility that they may be forming stars. A complete understanding of elliptical galaxy evolution depends on knowing the origin and the fate of this neutral gas and the star formation rate in elliptical galaxies. High resolution images made from observations of the carbon monoxide (CO) and hydrogen (HI) emission lines from nine elliptical galaxies will be made with the Berkeley, Illinois, and Maryland (BIMA) and Owens Valley Radio Observatory (OVRO) millimeter wavelength radio telescope interferometers and with the Very Large Array (VLA) radio telescope. The analysis of the data on the neutral gas distribution and kinematics will give vital clues to its origin and its fate. For example, the analysis of the data will show whether the gas was acquired in a violent merger, whether the gas is forming stars, is feeding an active galactic nucleus, or is being destroyed by some other process. The knowledge about the gas distribution and kinematics will also help explain the origin of the radio-FIR correlation in elliptical galaxies and will reveal the effects of a galaxy's environment on its neutral gas.The answers to these questions are not known because there are very few elliptical galaxies with good data on the distribution of their molecular and atomic gas. The results from this project will more than double the number of elliptical galaxies with good CO and HI emission line maps. The sample galaxies have a wide range of properties (including environment, morphology, luminosity. and strength of nuclear continuum source), that will help to disentangle the many processes affecting elliptical galaxies. The result from the project will be a unique synthesis of information that will help to give a better global picture of elliptical galaxies and their interstellar media. The project's results on the star formation rates in individual elliptical galaxies will be combined with the statistical work of Cotton & London (1998) to give the first quantitative picture of star formation in elliptical galaxies. The results of this project will also he used to refine the theoretical models of elliptical galaxy evolution. Finally, by showing how elliptical galaxies are evolving today, the project will help to draw the connections between high redshift and low redshift galaxies.This project is funded by the Division of Astronomical Sciences and the Office of Multidisciplinary Activities in the Mathematical and Physical Sciences Directorate.***