• S. H. Li

      Articles written in Journal of Astrophysics and Astronomy

    • Relativistic Beaming Effect in Fermi Blazars

      J. H. Fan D. Bastieri J. H. Yang Y. Liu D. X. Wu S. H. Li

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      The most identified sources observed by Fermi/LAT are blazars, based on which we can investigate the emission mechanisms and beaming effect in the 𝛾-ray bands for blazars. Here, we used the compiled around 450 Fermi blazars with the available X-ray observations to estimate their Doppler factors and compared them with the integral 𝛾-ray luminosity in the range of 1–100 GeV. It is interesting that the integral 𝛾-ray luminosity is closely correlated with the estimated Doppler factor, log 𝑣𝛾 𝐿𝑣𝛾 = (2.95 ± 0.09) log 𝛿 + 43.59 ± 0.08 for the whole sample. When the dependence of the correlation between them and the X-ray luminosity is removed, the correlation is still strong, which suggests that the 𝛾-ray emissions are strongly beamed.

    • Correlation between 𝛾-Ray and Radio Bands for 𝛾-Ray Loud Blazars

      D. X. Wu J. H. Fan S. H. Li

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      The most identified sources observed by Fermi are blazars (Flat Spectrum Radio Quasars (FSRQs) and BL Lacertae objects (BLs). In this paper, we obtained 124 𝛾-ray loud blazars with available 𝛾-ray and radio (core and total) data. It is interesting that the 𝛾-ray luminosity have a good correlation with the radio luminosity. This phenomenon exists in the core radio luminosity (𝐿c) and total radio luminosity (𝐿t). The correlation between the 𝛾-ray and the radio luminosities is still stronger even after we eliminated the redshift effect, which suggests that the 𝛾-ray radiations in the 𝛾-ray loud blazars are strongly beamed.

    • Core Dominance Parameter for 𝛾-Ray Loud Blazars

      S. H. Li J. H. Fan D. X. Wu

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      In this paper, we compiled 572 blazars that have known core dominance parameter (log 𝑅), out of which 121 blazars are 𝛾-ray loud blazars. We compared log 𝑅 between 121 blazars and the rest with non 𝛾-ray detections, and found that 𝛾-ray loud blazars showed a different distribution, and their average value of log 𝑅 is greater than that for non 𝛾-ray blazars. Our analysis suggests that the 𝛾-ray emissions are strongly beamed.

    • Correlation between Spectral Index and Doppler Factor for a Sample of Fermi Blazars

      J. Tao J. H. Fan H. J. Pan D. X. Wu S. H. Li

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      Relativistic beaming effect is important for blazars. In a very recent work, 𝛾-ray Doppler factors were calculated for a sample of Fermi blazars (Fan et al. 2013). In this work, we investigated the correlation between the Doppler factor and the effective spectral index, 4𝛼OX, and found an anticorrelation between them.

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    • Continuous Article Publication

      Posted on January 27, 2016

      Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately. All these have helped shorten the publication time and have improved the visibility of the articles.

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