Light speed variation from active galactic nuclei

TL;DR

This paper investigates potential light speed variation with photon energy using observations from active galactic nuclei, supporting previous findings from gamma-ray bursts and suggesting energy-dependent photon velocities.

Contribution

It extends the analysis of light speed variation to AGN light curves, providing additional observational support for energy-dependent photon velocities.

Findings

Supports light speed variation from AGN light curves

Corroborates previous GRB-based results

Suggests energy-dependent photon velocities

Abstract

Recent studies on the high-energy photons from gamma-ray bursts~(GRBs) suggested a light speed variation $v(E)=c(1-E/E_{\mathrm{LV}})$ with $E_\mathrm{LV}=3.6\times 10^{17}$ GeV. We check this speed variation from previous observations on light curves of three active galactic nuclei (AGNs), namely Markarian 421 (Mrk 421), Markarian 501 (Mrk 501) and PKS 2155-304. We show that several phenomena related to the light curves of these AGNs can serve as the supports for the light speed variation determined from GRBs.