English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

In this paper, we compile the very-high-energy and high-energy spectralindices of 43 BL Lac objects from the literature. Based on a simple math model,$\Delta\Gamma_{obs}=\alpha {\rm{z}}+\beta $, we present evidence for the originof an observed spectral break that is denoted by the difference between theobserved very-high-energy and high-energy spectral indices,$\Delta\Gamma_{obs}$. We find by linear regression analysis that $\alpha\ne 0$and $\beta\ne 0$. These results suggest that the extragalactic background lightattenuation and the intrinsic curvature dominate on the GeV-TeV $\gamma$-rayenergy spectral break of BL Lac objects. We argue that the extragalacticbackground light attenuation is an exclusive explanation for the redshiftevolution of the observed spectral break.

GeV-TeV $\gamma$-ray energy spectral break of BL Lac objects