Abstract
Based on Fermi 1FGL and 2FGL data, a sample of 572 γ-ray loud blazars are selected, in which each sources has both γ-ray flux and spectral index in 1FGL and 2FGL, respectively. Theoretic relation of spectral index changes depending on γ-ray brightness is obtained. The correlations between the ratio of γ-ray flux densities and the differences of the γ-ray spectral indices are discussed for the three subclasses of HBL, LBL and FSRQs. Results show that the ratio is related with the differences for the three subclasses. It is consistent with the theoretical result and it indicates that the spectrum becomes flat as the source brightens in the γ-ray band.
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Acknowledgements
The work is partially supported by the National Natural Science Foundation of China (NSFC 11173009, NSFC 11203007), the research fund of Hunan University of Arts and Science (JJZD 201101), the Bureau of Education of Guangzhou Municipality (No. 11 Sui-Jiao-Ke [2009]), Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme (GDUPS) (2009), Yangcheng Scholar Funded Scheme (10A027S), and support for Astrophysics Key Subject of Guangzhou City.
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Yang, J.H., Yang, R.S., Nie, J.J. et al. Spectral Index Changes with Brightness for γ-Ray Loud Blazars. J Astrophys Astron 35, 401–404 (2014). https://doi.org/10.1007/s12036-014-9241-9
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DOI: https://doi.org/10.1007/s12036-014-9241-9