Theoretical Studies of Astronomical Masers

来自甚长基线阵列（VLBA）无线电设备的高分辨率数据以及来自红外天文卫星（IRAS）和红外空间天文台（ISO）的宽视场数据为自然发生的脉泽过程提供了丰富的新信息。年轻恒星和垂死恒星膨胀的大气层，超新星残骸的膨胀碎片，以及其他星系中巨大的恒星形成区域，在红外和微波区域都比它们的物理温度所暗示的要亮得多，这表明脉泽活动正在发生。像h2o、OH和SiO这样的分子被热尘埃发出的红外辐射大力“泵送”，或者在某些情况下，通过与中性“风”粒子的直接碰撞。这类物质以特定的准直长波光子的形式释放这种能量。这些都是需要理解的关键过程，因为在这种条件下，大多数恒星的很大一部分质量都会返回到星际介质中。这项拨款支持对各种天文脉泽源进行理论研究。计算模型将考虑光子辐射和流体动压、加速度和尘埃的加热。目标是通过在现有代码中包含热能平衡计算来实现观测和模型之间的良好一致性。

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.