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Radio spectral index of BL Lac objects

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Abstract

In this paper, the preliminary data from University of Michigan Radio Astronomy Observatory database (UMRAO) are used to discuss the radio spectral index properties of 8 BL Lacs. To do so, we calculated the radio spectral index, α (F ∝ ν α), which was obtained by fitting the averaged flux densities in the bands (4.8 GHZ, 8 GHz, and 14.5 GHz) by binning the original for 7 d. We also calculated the time delay between the averaged lightcurves and the spectral variance. Our calculations and analysis give the following results. 1) The averaged logarithmic flux density at 8 GHz (logF) and the corresponding spectral index (α) have strong correlation for all the BL Lacs; 2) the lightcurves and the spectral variability have the similar profile for all the BL Lacs; 3) the lightcurves delay spectral variability for all sources but PKS 0735+178, with the delay time ranging from 31 d to 125 d.

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  1. Center for Astrophysics, Guangzhou University, Guangzhou, 510006, China

    YuHai Yuan, JunHui Fan & **aoLi Long

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  1. YuHai Yuan
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Correspondence to YuHai Yuan.

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Yuan, Y., Fan, J. & Long, X. Radio spectral index of BL Lac objects. Sci. China Phys. Mech. Astron. 56, 1035–1040 (2013). https://doi.org/10.1007/s11433-013-5058-9

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