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国家自然科学基金(10903025)

作品数:3 被引量:1H指数:1
相关作者:张晓辉李少昆更多>>
相关机构:中国科学院中国科学院云南天文台邯郸学院更多>>
发文基金:国家自然科学基金国家重点基础研究发展计划更多>>
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A puzzle of the radio-quiet quasar PG 1407+265:Are optical and X-ray emissions produced from a relativistic jet?
2011年
PG 1407+265 is a radio quiet quasar that has a relativistic jet.In this report,we show some peculiar properties of its optical and X-ray emissions,which indicate possible non-thermal origins produced from the jet.We use a simple synchrotron + synchrotron self Compton (SSC) model to fit the emissions with different ratios of energy densities between the magnetic field and electrons (η≡U B/U e),which predicts a different γ-ray luminosity.The First LAT AGN Catalog (1LAC) did not include PG 1407+265,which indicates an upper limit of γ-ray luminosity.This upper limit constrains the ratio to be unreasonably large (η≥10 4-5).This inversely indicates that the optical and X-ray emissions may not be produced from the beaming jet.We discuss the physical implications of these results.
CHEN Liang 1,2,3 & BAI JinMing 1,2 1 National Astronomical Observatories/Yunnan Observatory,Chinese Academy of Sciences,Kunming 650011,China
关键词:JET
The connection between radio and γ-ray emission in Fermi/LAT blazars
2012年
We collect the second Large Area Telescope AGN catalog (2LAC) and Monitor of Jets in AGN with VLBA Equipment (MOJAVE) quasi-simultaneous data to investigate the radio-γ connection of blazars. The cross sample contains 166 sources. The statistical analysis based on this sample confirms positive correlations between these two bands, but the correlations become weaker as the γ-ray energy increases. The statistical results between various parameters show negative correla- tions of γ-ray photon spectral index with γ-ray loudness for both Flat Spectrum Radio Quasars (FSRQs) and BL Lacertae objects, positive correlations of γ-ray variability index with the γ-ray loudness for FSRQs, a negative correlation of the γ-ray variabil- ity index with the γ-ray photon spectral index for FSRQs, and negative correlations of γ-ray photon spectral index with γ-ray luminosity for FSRQs. These results suggest that the γ-ray variability may be due to changes inside the γ-ray emission region like the injected power, rather than changes in the photon density of the external radiation fields, and the variability amplitude tends to be larger as the γ-rays are closer to the high energy peak of the spectral energy distribution (SED). No correlation of variabil- ity index found for BL Lacertae objects implies that variability behavior may differ below and above the peak energy.
Xu-Liang FanJin-Ming BaiHong-Tao LiuLiang ChenNeng-Hui Liao
有舍弃的装箱问题及其启发式算法被引量:1
2012年
设计了一种启发式算法——RCF算法来解决有舍弃装箱问题.实验证明,该算法与RFF3算法相比,在物体个数比较少(<200)的情况下,由于数据的随机性会出现比RFF3算法较好;在物体个数大于200的情况下,RFF3算法具有绝对的优势.因此,提出的RCF算法在物体个数比较少的情况下,有一定的应用价值.
龚淑梅张晓辉李少昆
关键词:装箱问题启发式算法
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