Theoretical Studies of Astronomical Masers

天文微波激射器的理论研究

• 批准号: 9819368
• 负责人: Moshe Elitzur
• 金额: $ 15.62万
• 依托单位: University of Kentucky Research Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-01 至 2003-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9819368&HistoricalAwards=false
• 关键词: Theoretical; Studies; Astronomical; Masers

ABSTRACTElitzur, MosheAST-9819368The high-resolution data now obtainable from the Very Long Baseline Array (VLBA) radio facility and wide-field data from the Infra-Red Astronomical Satellite (IRAS) and Infra-red Space Observatory (ISO) have provided a wealth of new information on naturally occurring maser processes. The extended atmospheres of both young and dying stars, the expanding debris of supernova remnants, and the large star-forming regions in other galaxies are all much brighter in the infrared and microwave region than their physical temperatures would imply, suggesting that maser activity is occurring. Molecules such as H20, OH and SiO are energetically 'pumped' by the IR radiation emitted by hot dust or, in some cases, by direct collisions with neutral 'wind' particles. Such species release this energy in the form of specific well-collimated long-wavelength photons. These are crucial processes to understand, since a large fraction of most stars' mass is returned to the interstellar medium under such conditions. This grant supports a theoretical study of a broad variety of astronomical maser sources. The computed models will take into account the photon radiation and hydrodynamic pressure, accelerations and heating of dust. The goal is to achieve a good agreement between observations and models by including thermal energy balance computations into the existing code.

Elitzur，MosheAST-9819368现在从甚长基线天线阵（VLBA）无线电设施获得的高分辨率数据和从红天文卫星（IRAS）和红空间天文台（ISO）获得的宽视场数据提供了大量关于自然发生的脉泽过程的新信息。 年轻恒星和垂死恒星的大气层，超新星残骸的膨胀碎片，以及其他星系中的大型恒星形成区域，在红外和微波区域都比它们的物理温度要亮得多，这表明微波激射活动正在发生。 H2O、OH和SiO等分子被热尘埃发出的红外辐射或在某些情况下与中性“风”粒子直接碰撞而被能量“泵浦”。 这些物质以特定的准直长波长光子的形式释放这种能量。 这些都是理解的关键过程，因为大多数恒星的大部分质量都是在这种条件下返回星际介质的。 该基金支持对各种各样的天文微波激射源进行理论研究。 计算模型将考虑尘埃的光子辐射和流体动力学压力、加速度和加热。 我们的目标是通过将热能平衡计算纳入现有代码来实现观测和模型之间的良好一致性。