Revisiting the TeV flare of PKS 2155-304 in 2006

Fuente: arXiv
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Main Authors: Tan, Hong-Bin, Liu, Ruo-Yu, Böttcher, Markus
Format: Preprint
Published: 2023
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author Tan, Hong-Bin
Liu, Ruo-Yu
Böttcher, Markus
author_facet Tan, Hong-Bin
Liu, Ruo-Yu
Böttcher, Markus
contents Blazars, a subclass of active galactic nuclei (AGN), are known to be bright $γ$-ray sources, frequently exhibiting active (flaring) periods. The blazar PKS~2155-304 is a high synchrotron-peaked BL Lac object located at redshift $z=0.116$. On 2006 July 28, an extremely remarkable outburst of VHE $γ$-ray emission from this blazar was reported by the H.E.S.S. experiment, with an average flux more than 10 times the low-state level. The variability timescale of this extraordinary flare was as short as approximately 200~s. In order to guarantee the transparency of the emission region for TeV photons, the fast variability demands an extremely high Doppler factor $δ_{\rm D}>50$ of the jet within the classical one-zone model, leading to the so-called "Doppler factor crisis". Here we demonstrate that the stochastic dissipation model, which is a multi-blob scenario for blazars, can self-consistently explain the giant TeV flares of PKS~2155-304 and the low-state emission before and after the flares, in terms of both multi-wavelength spectral and variability characteristics. The required Doppler factor in this model can be as low as 20, which is a reasonable and typical value for blazar jets. The obtained model parameters may shed some light on the physical properties of the relativistic jet.
format Preprint
id arxiv_https___arxiv_org_abs_2311_13873
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Revisiting the TeV flare of PKS 2155-304 in 2006
Tan, Hong-Bin
Liu, Ruo-Yu
Böttcher, Markus
High Energy Astrophysical Phenomena
Blazars, a subclass of active galactic nuclei (AGN), are known to be bright $γ$-ray sources, frequently exhibiting active (flaring) periods. The blazar PKS~2155-304 is a high synchrotron-peaked BL Lac object located at redshift $z=0.116$. On 2006 July 28, an extremely remarkable outburst of VHE $γ$-ray emission from this blazar was reported by the H.E.S.S. experiment, with an average flux more than 10 times the low-state level. The variability timescale of this extraordinary flare was as short as approximately 200~s. In order to guarantee the transparency of the emission region for TeV photons, the fast variability demands an extremely high Doppler factor $δ_{\rm D}>50$ of the jet within the classical one-zone model, leading to the so-called "Doppler factor crisis". Here we demonstrate that the stochastic dissipation model, which is a multi-blob scenario for blazars, can self-consistently explain the giant TeV flares of PKS~2155-304 and the low-state emission before and after the flares, in terms of both multi-wavelength spectral and variability characteristics. The required Doppler factor in this model can be as low as 20, which is a reasonable and typical value for blazar jets. The obtained model parameters may shed some light on the physical properties of the relativistic jet.
title Revisiting the TeV flare of PKS 2155-304 in 2006
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2311.13873