物理与电子工程学院2018学术论坛之四十
报告时间：2018年11月23日（周五）14:00-15:30
报告地点：理学实验楼717
题目：RadioAstron space-VLBI project: studies of masers in star forming regions of our Galaxy and megamasers in external galaxies
报告人: Andrey Sobolev教授 (Ural Federal University)
报告人简介：Sobolev教授在1989年-2018年担任俄罗斯乌尔拉联邦大学Kourovka天文台天体物理和太阳物理学的系主任。2016年至今，他担任Kourovka天文台的执行董事，2018年起担任Kourovka天文台的首席研究员。他是天体脉泽研究和空间VLBI技术应用的专家，目前是空间VLBI项目RadioAstron的成员，该项目在极高角分辨率下研究脉冲星、耀变体、天体脉泽等。
报告摘要：Observations of the masers in the course of RadioAstron mission yielded detections of fringes for a number of sources in both water and hydroxyl maser transitions. Several sources display numerous ultra-compact details. This proves that implementation of the space VLBI technique for maser studies is possible technically and is not always prevented by the interstellar scattering, maser beaming and other effects related to formation, transfer and detection of the cosmic maser emission.
For the first time cosmic water maser emission was detected with projected baselines exceeding Earth Diameter. It was detected in a number of star forming regions in the Galaxy and megamaser galaxies NGC 4258 and NGC 3079. RadioAstron observations provided absolute record of the angular resolution in astronomy. Fringes from the NGC 4258 megamaser were detected on baseline about 26.7 Earth Diameters (~340,000 km). This means that the angular resolution about 8 μas was directly achieved in the cosmic maser observations.
The major step from milli- to micro-arcsecond resolution in maser studies is done in the RadioAstron mission. Existence of maser features with extremely small angular sizes is established. Further implementations of the space VLBI maser instrument for studies of the nature of cosmic objects, studies of interaction of extremely high radiation field with molecular material and studies of the matter on the line of sight are planned
