Models of Extragalactic Jets

河外喷流模型

• 批准号: 8717912
• 负责人: Paul Wiita
• 金额: $ 5.7万
• 依托单位: Georgia State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-07-15 至 1990-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8717912&HistoricalAwards=false
• 关键词: Models; Extragalactic; Jets

Models of extragalactic radio jets will be constructed using a variety of numerical approaches. An essentially three-dimensional boundary-following code will be used to continue to investigate the formation and evolution of radio jets. In particular, the bending of jets by ram pressure as the central galactic source moves through an external medium, the growth of non-axisymmetric instabilities, and the effects of a precessing source of jet fluid, will all be studied. Recently developed analytic models of jet propagation from a galactic halo across a pressure-matched interface into an extremely hot intergalactic medium will be developed further. Preliminary calculations using this idea seem to provide good explanations for both the current average size of strong radio sources and the fact the such sources were significantly samller at earlier cosmological epochs. Numerical models of this situation will be developed using both the three-dimensional boundary following code and a full two-dimensional hydrodynamics code and more detailed comparisons with statistical data will be made. Analytic models for jet instabilities will be applied to Very Large Array (VLA) radio maps of a particularly interesting radio source with a single, oscillatory jet feeding into a diffuse lobe. A general model for the continuum electromagnetic emission from active galactic nuclei, based on coherent plasma processes, will be further developed and compared with observations.

将使用各种数值方法构建河外射电喷流模型。 本质上是三维边界跟踪代码将用于继续研究无线电射流的形成和演化。 特别是，当中央星系源移动通过外部介质时，冲压压力引起的喷流弯曲、非轴对称不稳定性的增长以及喷流流体进动源的影响都将被研究。 最近开发的射流从星系晕穿过压力匹配界面进入极热星系际介质传播的分析模型将得到进一步开发。 使用这一想法的初步计算似乎为当前强射电源的平均大小以及此类源在早期宇宙学时代明显较小的事实提供了很好的解释。 这种情况的数值模型将使用三维边界跟踪代码和完整的二维流体动力学代码来开发，并将与统计数据进行更详细的比较。 射流不稳定性的分析模型将应用于特别有趣的射电源的甚大阵列（VLA）射电图，其中单个振荡射流馈入扩散波瓣。 将进一步开发基于相干等离子体过程的活动星系核连续电磁发射的通用模型，并与观测结果进行比较。