High-energy variability of the gravitationally lensed blazar PKS 1830-211

Fuente: arXiv
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Autores principales: Wagner, Sarah M., Scargle, Jeffrey D., Madejski, Greg, Gokus, Andrea, Nalewajko, Krzysztof, Günther, Patrick, Mannheim, Karl
Formato: Preprint
Publicado: 2025
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author Wagner, Sarah M.
Scargle, Jeffrey D.
Madejski, Greg
Gokus, Andrea
Nalewajko, Krzysztof
Günther, Patrick
Mannheim, Karl
author_facet Wagner, Sarah M.
Scargle, Jeffrey D.
Madejski, Greg
Gokus, Andrea
Nalewajko, Krzysztof
Günther, Patrick
Mannheim, Karl
contents The production site and process responsible for the highly variable high-energy emission observed from blazar jets are still debated. Gravitational lenses can be used as microscopes to investigate the nature of such sources. We study the broad-band spectral properties and the high-energy variability of the gravitationally-lensed blazar PKS 1830-211, for which radio observations have revealed two images, to put constraints on the jet physics and the existence of a gravitationally-induced time delay and magnification ratio between the images. We utilize Swift/XRT, Nustar, and Fermi-LAT observations from 2016 and 2019 to compare periods of low activity and high activity in PKS 1830-211. Short-timescale variability is elucidated with an unbinned power spectrum analysis of time-tagged NuSTAR photon data. To study the gravitationally-induced time delay in the gamma-ray light curve observed with Fermi-LAT, we improve existing autocorrelation function based methods. Our modified auto-correlation method yields a delay of t_0=21.1 +/- 0.1 d and magnification factor a=0.13 +/- 0.01. These parameters remain time-invariant. In data from 2016 and 2019, the X-ray spectra remain remarkably stable, contrasting with extreme changes in gamma-rays. Both states can be fitted with a single component from Comptonisation of infrared emission from the dusty torus, with different gamma-ray states arising solely from a shift in the break of the electron energy distribution. The detection of a consistent lag throughout the whole light curve suggests that they originate from a persistent location in the jet.
format Preprint
id arxiv_https___arxiv_org_abs_2510_07220
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle High-energy variability of the gravitationally lensed blazar PKS 1830-211
Wagner, Sarah M.
Scargle, Jeffrey D.
Madejski, Greg
Gokus, Andrea
Nalewajko, Krzysztof
Günther, Patrick
Mannheim, Karl
High Energy Astrophysical Phenomena
Cosmology and Nongalactic Astrophysics
The production site and process responsible for the highly variable high-energy emission observed from blazar jets are still debated. Gravitational lenses can be used as microscopes to investigate the nature of such sources. We study the broad-band spectral properties and the high-energy variability of the gravitationally-lensed blazar PKS 1830-211, for which radio observations have revealed two images, to put constraints on the jet physics and the existence of a gravitationally-induced time delay and magnification ratio between the images. We utilize Swift/XRT, Nustar, and Fermi-LAT observations from 2016 and 2019 to compare periods of low activity and high activity in PKS 1830-211. Short-timescale variability is elucidated with an unbinned power spectrum analysis of time-tagged NuSTAR photon data. To study the gravitationally-induced time delay in the gamma-ray light curve observed with Fermi-LAT, we improve existing autocorrelation function based methods. Our modified auto-correlation method yields a delay of t_0=21.1 +/- 0.1 d and magnification factor a=0.13 +/- 0.01. These parameters remain time-invariant. In data from 2016 and 2019, the X-ray spectra remain remarkably stable, contrasting with extreme changes in gamma-rays. Both states can be fitted with a single component from Comptonisation of infrared emission from the dusty torus, with different gamma-ray states arising solely from a shift in the break of the electron energy distribution. The detection of a consistent lag throughout the whole light curve suggests that they originate from a persistent location in the jet.
title High-energy variability of the gravitationally lensed blazar PKS 1830-211
topic High Energy Astrophysical Phenomena
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2510.07220