An accretion-jet model for 3C 84: Interpreting the spectral energy distribution and Faraday rotation measure     

Jianchao Feng  Xiaowen Wang  Rui Jing 《Astronomische Nachrichten》2024,345(2-3):e230175

3C 84 is a well-known supermassive black hole that can be used to explore jet and accretion physics. In this work, we model the multiwavelength spectral energy distribution (SED) of the 3C 84, and find that the SED is difficult to fit with pure advection dominated accretion flow (ADAF) or pure jet model. Using a coupled ADAF-jet model to fit the SED of 3C 84, it is found that the radio emission and the millimeter emission can be naturally reproduced by the synchrotron radiation of nonthermal electrons in the jet, and that the X-ray emission may predominantly come from inverse Compton radiation from electrons in ADAF. According to the Rotation Measure (RM) obtained by the polarization observation, we consider the possible location of the polarizing source and found that the calculated RM in the jet is roughly consistent with the observational constraints. These results will help us better understand jets produced by black holes.  相似文献   

WGS84和CGCS2000坐标转换研究     

彭小强  高井祥  王坚 《大地测量与地球动力学》2015,35(2):219-221

为实现WGS84和CGCS2000坐标系之间的转换,首先通过七参数法将WGS84坐标转换到ITRF坐标,然后再通过框架转换法转换到CGCS2000坐标,并进行实例计算和分析。  相似文献   

WGS-84与西安80坐标转换研究     

马家琼;杨晓英;崔文刚;陈涛;胡君 《东北测绘》2013,(4):158-160

伴随着坐标转换问题成为诸多项目研究热点,在进行不同国家坐标系以及国家坐标系与地方独立坐标系之间的坐标转换时问题层出不穷。通过坐标转换,实现了不同坐标系下数据与数据之间转换精度研究及影像与数据叠合精度分析。本文就WGS-84与西安80坐标转换问题进行探讨。  相似文献   

EXPLANATIONS FOR THE INTENSIFICATION OF COUNTERURBANIZATION IN THE FEDERAL REPUBLIC OF GERMANY *     

Thomas Kontuly  Roland Vogelsang 《The Professional geographer》1988,40(1):42-54

Evaluating yearly net migration for the Federal Republic of Germany establishes the importance of demographic restructuring and government policies as explanations for the counterurbanization phenomenon. Counterurbanization, the spatial demographic deconcentration of regional population, is measured as an inverse relationship between the net migration rate and population sizes of functional urban regions. A counterurbanization pattern filtered-down from older to younger age-groups of the population, and appears related to an increasing preference for small-sized regions with natural amenities. For foreigners, a counterurbanization direction of movement can be explained by changes in immigration laws. While counterurbanization may be slowing down during the 1980s in certain developed countries, such as the United States, in the Federal Republic the phenomenon intensifies throughout the 1970–84 time period. Based on broad national demographic changes in combination with agespecific patterns of movement, this strong counterurbanization trend should continue well into the future.  相似文献   

基于WGS-84椭球面的退化四叉树经纬线格网剖分     

胡佰林  王春波  赵学胜  崔马军 《测绘学报》2016,45(Z1):32-39

针对数字地球的发展和解决全球问题的需求,给出了一种基于WGS-84椭球面的全球离散格网剖分方法——退化四叉树经纬线格网;分析了格网剖分的特点,明确了格网单元行列定义和经纬度坐标;计算出不同剖分层次格网单元面积、边长的变化情况并与基于正球面的剖分进行了对比。结果表明该格网系统具有粒度相对均匀性、层次嵌套性、方向一致性、地理条带性和对称性、广泛数据兼容性等许多优良特征,对构建全球地理信息系统具有一定的实用价值。  相似文献   

RTK测量中基准站的设置问题     

翟翠允  段凌燕  耿志军  薄振龙  贾黎君  张军 《海洋测绘》2007,27(3):63-65

介绍了GPS单点定位及RTK的工作原理,并结合基本原理,对RTK测量中基准站的设置方法进行说明,并着重分析1 n RTK测量中,n台手簿在基准站设置中容易进入的误区,并结合实验数据进行了分析说明,找出错误原因,最后得出基准站正确的设置方法。  相似文献   

RTK技术在平面坐标转换中的应用     

侯新军  赵迎红 《山东国土资源》2007,23(12):3-5

RTK技术的测量成果是WGS-84坐标系下的数据,在实际工作中一般使用国家坐标系或地方坐标系,需要将WGS-84坐标进行坐标转换。该文通过实际测量,介绍了2种坐标系统间平面坐标转换的方法及其数学模型。  相似文献   

WGS-84坐标系和西安80坐标系转换方法及精度分析——基于新疆兵团C、D级GPS网成果   总被引：1，自引：0，他引：1  

高永甲  臧登峰 《测绘工程》2009,18(3):55-57

根据新疆兵团C、D级GPS网中的重合三角点、GPS2000网联合平差点、天文点成果，采用二维高斯平面坐标转换模型和Bursa七参数转换模型，完成WGS-84坐标系与80西安坐标系转换参数的计算与精度分析。  相似文献   

坐标转换参数的求解方法及其应用     

陈贻胜 《上海国土资源》2006,(2):53-56

根据坐标转换参数的解算模型,介绍几种常见的坐标转换参数的求解方法及其参数个数与精度;探讨选择坐标转换参数的条件及转换参数的应用,从而阐明转换参数对GPS技术的推广和全球资料的统一的重要作用。  相似文献   

GPS测量在石油地球物理勘探中的应用     

张秀胜  李德民 《测绘与空间地理信息》2002,25(3):79-80

简要叙述GPS技术在我国石油地球物理勘探中的应用以及这种方法在具体应用中体现出的优越性和它的发展前景。  相似文献