Constraining $\gamma$-ray dissipation site in gravitationally lensed quasar -- PKS 1830$-$211

Abstract

Variable $\gamma$-ray flares upto minute timescales reflect extreme particle acceleration sites. However, for high-redshift blazars, the detection of such rapid variations remains limited by current telescope sensitivities. Gravitationally lensed blazars serve as powerful tools to probe $\gamma$-ray production zones in distant sources, with time delays between lensed signals providing crucial insights into the spatial distribution of emission regions relative to the lens's mass-weighted center. We have utilized 15 years of Fermi-LAT $\gamma$-ray data from direction of PKS 1830$-$211 to understand the origin of flaring high-energy production zone at varying flux states. To efficiently estimate the (lensed) time delay, we used a machine learning-based tool - the Gaussian Process regression algorithm, in addition to - Autocorrelation function and Double power spectrum. We found a consistent time delay across all flaring activity states, indicating a similar location for the $\gamma$-ray emission zone, possibly within the radio core. The estimated time delay of approximately 20 days for the five flaring epochs was significantly shorter than previously estimated radio delays. This suggests that the $\gamma$-ray emission zone is closer to the central engine, in contrast to the radio emission zone, which is expected to be much farther away. A linear relationship between lag and magnification has been observed in the identified source and echo flares. Our results suggest that the $\gamma$-ray emission zone originates from similar regions away from the site of radio dissipation.

11 pages, 10 figures, 3 tables. Accepted for publication in MNRAS

References in corpus (13)

• MAGIC discovery of VHE Emission from the FSRQ PKS 1222+21
• A method for the estimation of the significance of cross-correlations in unevenly sampled red-noise time series
• Stochastic Modeling of the Fermi/LAT Gamma-ray Blazar Variability
• Gamma-ray flaring activity from the gravitationally lensed blazar PKS 1830-211 observed by Fermi LAT
• Fourier Analysis of Blazar Variability
• Filamentary structures as the origin of blazar jet radio variability
• A Python Code for the Emmanoulopoulos et al. [arXiv:1305.0304] Light Curve Simulation Algorithm
• Multiwavelength variability power spectrum analysis of the blazars 3C 279 and PKS 1510-089 on multiple timescales
• Flux Distribution of Gamma-Ray Emission in Blazars: The Example of Mrk 501
• All good things come in threes: the third image of the lensed quasar PKS1830-211
• Flaring activity from magnetic reconnection in BL Lacertae
• Statistical properties of flux variations in blazar light curves at GeV and TeV energies
• Imprint of "Local Opacity" Effect in Gamma-Ray Spectrum of Blazar Jet