| On the Spectral Index－Flux Density Relation for Large Samples of Radio Sources |
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| 作者姓名： | W.Reich P.Reich R.Wielebinski |
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| 作者单位： | Max-Planck-Institut fr Radioastronomie，Auf dem Hgel 69，D-53121 Bonn，Germany，Max-Planck-Institut fr Radioastronomie，Auf dem Hgel 69，D-53121 Bonn，Germany，Max-Planck-Institut fr Radioastronomie，Auf dem Hgel 69，D-53121 Bonn，Germany |
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| 基金项目： | National Natural Science Foundation of China. |
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| 摘 要： | We present new statistical results on the spectral index-flux density relation for large samples of radio sources using archival data of the most sensitive surveys, such as 6C, Miyun, WENSS, B3, NVSS, GB87. Instrumental selection effects and the completeness of the catalogs are discussed. Based on the spectral indices calculated for about 200 000 sources from the WENSS (327 MHz) and NVSS (1.4 GHz) catalogs, we obtained (1) The median spectral index increases from amed --0.9 toαmed --0.8 (Svαvα), while S327 flux densities decrease from 0.1 Jy down to 25mJy. The median spectral indices nearly show no variation within the error bars when the flux density is larger than 0.1 Jy. (2) A dependence of the fraction of ultra-steep spectrum sources (USS, -1.5 <α<-1.0), steep spectrum sources (SSS, -1.0 <α< -0.5) and flat spectrum sources (FSS, -0.5≤α≤0.0) is partly responsible for the spectral flattening. Another contribution to the spectral flattening comes from the variation of αmed of steep spectrum so
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| 关 键 词： | 无线电天文学 无线电源 光谱分析 密度关系 统计分析 宇宙论 |
On the Spectral Index-Flux Density Relation for Large Samples of Radio Sources |
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| W.Reich,P.Reich,R.Wielebinski.On the Spectral Index-Flux Density Relation for Large Samples of Radio Sources[J].Chinese Journal of Astronomy and Astrophysics,2003,3(4):347-358. |
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| Authors: | Xi-Zhen Zhang WReich PReich RWielebinski |
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| Abstract: | |
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| Keywords: | radio continuum: general-methods: statistical - cosmology |
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