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Related papers: Reconnection-driven plasmoids in blazars: fast fla…

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Order of magnitude variability has been observed in the blazar sub-class of Active Galactic Nuclei on minute timescales. These high-energy flares are often difficult to explain with shock acceleration models due to the small size of the…

High Energy Astrophysical Phenomena · Physics 2019-06-12 Paul J. Morris , William J. Potter , Garret Cotter

Powerful flares from blazars with short ($\sim$ min) variability timescales are challenging for current models of blazar emission. Here, we present a physically motivated ab initio model for blazar flares based on the results of recent…

High Energy Astrophysical Phenomena · Physics 2016-09-07 Maria Petropoulou , Dimitrios Giannios , Lorenzo Sironi

Magnetic reconnection can power bright, rapid flares originating from the inner magnetosphere of accreting black holes. We conduct extremely high resolution ($5376\times2304\times2304$ cells) general-relativistic magnetohydrodynamics…

The multi-wavelength spectral and temporal variability observed in blazars set tight constraints on current theoretical emission models. Here, we investigate the relativistic magnetic reconnection process as a source of blazar emission in…

High Energy Astrophysical Phenomena · Physics 2018-12-04 I. M. Christie , M. Petropoulou , L. Sironi , D. Giannios

Measurements from astroparticle experiments, such as the 2017 flare associated with the source TXS 0506+056, indicate that blazars act as multi-messenger (MM; radiation and neutrinos) factories. Theoretically, the particle acceleration…

High Energy Astrophysical Phenomena · Physics 2025-02-18 E. M. de Gouveia Dal Pino , J. C. Rodríguez-Ramírez , M. V. del Valle

The ubiquitous relativistic jet phenomena associated with black holes play a major role in high and very-high-energy (VHE) astrophysics. In particular, observations have demonstrated that blazars show VHE emission with time-variability from…

High Energy Astrophysical Phenomena · Physics 2021-05-19 Luís H. S Kadowaki , Elisabete M. de Gouveia Dal Pino , Tania E. Medina Torrejon , Yosuke Mizuno , Pankaj Kushwaha

The evolution of the spectral energy distribution during flares constrains models of particle acceleration in blazar jets. The archetypical blazar BL Lac provided a unique opportunity to study spectral variations during an extended strong…

High Energy Astrophysical Phenomena · Physics 2023-03-15 S. Agarwal , B. Banerjee , A. Shukla , J. Roy , S. Acharya , B. Vaidya , V. R. Chitnis , S. M. Wagner , K. Mannheim , M. Branchesi

Fast $\gamma$-ray variability in blazars remains a central puzzle in high-energy astrophysics, challenging standard shock acceleration models. Blazars, a subclass of active galactic nuclei (AGN) with jets pointed close to our line of sight,…

High Energy Astrophysical Phenomena · Physics 2025-11-26 Chandan Kumar Das , Bhargav Vaidya , Amit Shukla , Giancarlo Mattia , Karl Mannheim

Relativistic jets from supermassive black holes are among the most powerful and luminous astrophysical systems in Universe. We propose that the open magnetic field lines through the black hole, which drive a strongly magnetized jet, may…

High Energy Astrophysical Phenomena · Physics 2021-01-13 Haocheng Zhang , Dimitrios Giannios

The origin of extremely fast variability is one of the long-standing questions in the gamma-ray astronomy of blazars. While many models explain the slower, lower energy variability, they cannot easily account for such fast flares reaching…

High Energy Astrophysical Phenomena · Physics 2023-10-18 J. Jormanainen , T. Hovatta , I. M. Christie , E. Lindfors , M. Petropoulou , I. Liodakis

Active Galactic Nuclei in general, and the supermassive black hole in M87 in particular, show bright and rapid gamma-ray flares up to energies of 100 GeV and above. For M87, the flares show multiwavelength components, and the variability…

High Energy Astrophysical Phenomena · Physics 2023-03-20 Hayk Hakobyan , Bart Ripperda , Alexander Philippov

Magnetic reconnection is thought to be one of the main energy-dissipation mechanisms fueling energy to the plasma in the vicinity of a black hole. Indeed, plasmoids formed through magnetic reconnection may play a key role in $\gamma$-ray,…

High Energy Astrophysical Phenomena · Physics 2022-06-01 Antonios Nathanail , Vasilis Mpisketzis , Oliver Porth , Christian M. Fromm , Luciano Rezzolla

We propose a new model for the description of ultra-short flares from TeV blazars by compact magnetized condensations (blobs), produced when red giant stars cross the jet close to the central black hole. Our study includes a simple…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Maxim V. Barkov , Felix A. Aharonian , Sergey V. Bogovalov , Stanislav R. Kelner , Dmitriy V. Khangulyan

We construct a numerical model of emission from minijets, localized flows driven by magnetic reconnection inside Poynting-flux-dominated jets proposed to explain the ultrafast variability of blazars. The geometrical structure of the model…

High Energy Astrophysical Phenomena · Physics 2015-05-19 Krzysztof Nalewajko , Dimitrios Giannios , Mitchell C. Begelman , Dmitri A. Uzdensky , Marek Sikora

The fast TeV variability of the blazars Mrk 501 and PKS 2155--304 implies a compact emitting region that moves with a bulk Lorentz factor of Gamma_{em}~100 toward the observer. The Lorentz factor is clearly in excess of the jet Lorentz…

High Energy Astrophysical Phenomena · Physics 2009-11-13 Dimitrios Giannios , Dmitri A. Uzdensky , Mitchell C. Begelman

Blazars are characterized by relativistic jets that are closely aligned with our line of sight. This results in relativistic beaming, making blazars among the most luminous extragalactic sources across the electromagnetic spectrum, from…

High Energy Astrophysical Phenomena · Physics 2025-07-14 Stamatios Ilias Stathopoulos , Maria Petropoulou

Rapid and luminous flares of non-thermal radiation observed in blazars require an efficient mechanism of energy dissipation and particle acceleration in relativistic active galactic nuclei (AGN) jets. Particle acceleration in relativistic…

High Energy Astrophysical Phenomena · Physics 2016-09-08 Krzysztof Nalewajko

It is commonly believed that blazar jets are relativistic magnetized plasma outflows from supermassive black holes. One key question is how the jets dissipate magnetic energy to accelerate particles and drive powerful multi-wavelength…

High Energy Astrophysical Phenomena · Physics 2022-01-26 Haocheng Zhang , Xiaocan Li , Dimitrios Giannios , Fan Guo , Hannes Thiersen , Markus Böttcher , Tiffany Lewis , Tonia Venters

Magnetic reconnection is often considered as the primary particle acceleration mechanism in a magnetized blazar zone environment. The majority of radiation in the reconnection layer comes from plasmoids and their mergers. In particular,…

High Energy Astrophysical Phenomena · Physics 2024-06-18 Haocheng Zhang , Lingyi Dong , Dimitrios Giannios

We show that magnetic reconnection in a magnetically-dominated fast-cooling plasma can naturally produce bright flares accompanied by rotations in the synchrotron polarization vector. With particle-in-cell simulations of reconnection, we…

High Energy Astrophysical Phenomena · Physics 2020-07-30 David N. Hosking , Lorenzo Sironi
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