Radio Polarization and Spectra of Variable Extragalactic Objects

河外可变物体的射电偏振和光谱

• 批准号: 8815678
• 负责人: Hugh Aller
• 金额: $ 55.24万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-01-01 至 1992-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8815678&HistoricalAwards=false
• 关键词: Radio; Polarization; Spectra; Variable; Extragalactic

Frequent measurements of the total flux density and linear polarization of extragalactic radio sources will be made at a frequency of 4.8, 8.0 and 14.5 GHz using the Michigan 26 meter radio telescope. Theoretical models will be developed and fitted to these data to study the physical conditions in the emitting regions and to study the particle energy generation mechanisms. These observations will be supplemented by Very Long Baseline Interferometry (VLBI) observations in collaboration with other researchers. Observations will also be made at 0.85, 1.4 and 2.7 GHz with the National Radio Astronomy Observatory 91 meter telescope to investigate the broad-band characteristics of low- frequency variable sources. Specific objectives of the research include: a) to obtain high time-resolution, multifrequency polarization and flux density data of isolated outbursts in order to test detailed theoretical models of the source emitting region, b) to develop more sophisticated models of shocks propagating in relativistic jet flows which constrain more of the physical parameters of the emitting regions, c) to better understand the relative importance of intrinsic and extrinsic and mechanisms as causes of decimetric variability, and the nature of the "intermediate frequency gap" , d) to improve global models of active galactic nuclei through simultaneous, broad- band (Ultraviolet or X-ray through radio wavelengths) observations, and e) to obtain morphological information of selected sources to test models of the emitting regions.

密歇根26米射电望远镜将在4.8 GHz、8.0 GHz和14.5 GHz频率上对河外射电源的总通量密度和线极化进行频繁测量。将根据这些数据建立和拟合理论模型，以研究发射区的物理条件和粒子能量产生机制。这些观测将由与其他研究人员合作的甚长基线干涉测量（VLBI）观测补充。国家射电天文台91米望远镜也将在0.85、1.4和2.7 GHz波段进行观测，以研究低频变源的宽带特性。研究的具体目标包括：A)获得孤立爆发的高时间分辨率、多频极化和通量密度数据，以便测试源发射区域的详细理论模型；b)开发更复杂的激波在相对论性射流中传播的模型，该模型约束了发射区域的更多物理参数；c)更好地理解作为分米变率原因的内在和外在机制的相对重要性，以及“中频间隙”的性质；d)通过同步的宽带（紫外线或射电波长的x射线）观测，改进活动星系核的全球模型；e)获取所选光源的形态信息，以测试发射区域的模型。