Lorentz invariance violation search with flaring active galactic nuclei observations of the first Large-Sized Telescope of CTAO

TL;DR

This study uses observations of active galactic nuclei from the CTAO's Large-Sized Telescope to search for potential Lorentz invariance violations by analyzing photon arrival time delays.

Contribution

It presents a standardized analysis of AGN data to constrain energy scales where Lorentz invariance violation effects might occur, addressing source-intrinsic uncertainties.

Findings

Constraints on LIV energy scales derived from AGN observations.

Systematic search for intra-night variability in archival data.

Combined observations improve LIV effect detection sensitivity.

Abstract

The rapid variability observed in very-high-energy (VHE) sources-such as pulsars, gamma-ray bursts (GRBs), and flares from active galactic nuclei (AGN)-can be used to detect or constrain a potential violation of Lorentz invariance (LIV). These effects can be investigated by measuring time lags in the arrival of VHE photons. However, an important source of uncertainty arises from intrinsic processes within the sources themselves that may induce photon delays unrelated to LIV. To address this challenge, we aim to combine observations of different sources, located at different redshifts. In this study, we present the results of a standardized analysis applied to all AGN observations conducted by the first Large-Sized Telescope of the upcoming Cherenkov Telescope Array Observatory. Our analysis includes a systematic search for intra-night variability in archival data from nights with significant excess detections for target candidates. By combining these observations, we derive constraints on the characteristic energy scales at which LIV deterministic or stochastic effects are expected to manifest.