Speaker
Description
The fast variability of very-high energy (VHE) sources such as pulsars, gamma-rays bursts (GRBs) or flares of active galactic nuclei (AGN) can be used to detect or constrain Lorentz invariance violation (LIV) by measuring lags in the arrival time of VHE photons. However, an important source of uncertainty arises from processes within the source that may induce intrinsic photon delays. Combining observations of different sources allows us to probe higher energy scales when LIV effects become relevant as well as to distinguish LIV-induced lags from intrinsic effects. We present the results of a standardized analysis performed on all AGN observations carried out by the first Large-Sized Telescope (LST-1) of CTAO. This analysis includes a general search of intra-night variability in archive observing nights that show significant excesses for the target candidates. The observing nights selected for LIV searches are then combined together to extract limits to the characteristic energies at which the LIV effect is expected to be significant. Finally, similar analysis have been performed on relevant data from other major imaging atmospheric Cherenkov telescopes, H.E.S.S., MAGIC and VERITAS, in order to combine all the data sets to extract combined limits that constrain one of the LIV effects.
| Collaboration(s) | CTAO |
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