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2. Discussion

Author

Ana Laura Müller

Published
2022

9. Non-thermal emission from fall-back clouds in the Broad-Line Region of Active Galactic Nuclei

Author

Anabella Araudo, Vladimir Karas, Ana Laura Müller, Mohammad-Hassan Naddaf, Michal Zajacek, and Bozena Czerny

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Space and Planetary Science, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies, Astrophysics::Galaxy Astrophysics
Abstract

The spectra of active galactic nuclei exhibit broad-emission lines that presumably originate in the Broad-Line Region (BLR) with gaseous-dusty clouds in a predominantly Keplerian motion around the central black hole. Signatures of both inflow and outflow motion are frequently seen. The dynamical character of BLR is consistent with the scenario that has been branded as the Failed Radiatively Accelerated Dusty Outflow (FRADO; Czerny & Hryniewicz 2011). In this scheme, frequent high-velocity impacts of BLR clouds falling back onto the underlying accretion disk are predicted. The impact velocities depend mainly on the black-hole mass, accretion rate, and metallicity and they range from a few km s$^{-1}$ up to thousands of km s$^{-1}$. Formation of strong shocks due to the collisions can give rise to the production of relativistic particles and associated radiation signatures. In this work, the non-thermal radiation generated in this process is investigated, and the spectral energy distributions for different parameter sets are presented. We find that the non-thermal processes caused by the impacts of clouds can lead to emission in the X-ray and the gamma-ray bands, playing the cloud density and metallicity a key role., 21 pages, 14 figures, and 2 tables. Accepted for publication in ApJ; extended Appendix

Published
2022
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11. Cosmic ray acceleration by multiple shocks in the jets of Active Galactic Nuclei

Author

Ana Laura Müller and Anabella Araudo

Subjects
General Medicine
Abstract

Active galactic nuclei are one of the most promising sources for accelerating particles up to the highest energies. In this contribution, we present a scenario in which cosmic rays are accelerated in multiple shocks created by the interaction of relativistic AGN jets with the winds of embedded massive stars. We solve the Fokker-Planck equation considering escape and radiative losses as well as the collective effect of the shocks and the reacceleration of the particles. Finally, we calculate the maximum energies that the particles can achieve and discuss the possibility of producing ultra-high energy cosmic rays in this astrophysical situation.

Published
2023

12. Measurement of the cosmic-ray energy spectrum above 2.5×1018 eV using the Pierre Auger Observatory

Author

Jaroslaw Stasielak, Ana Martina Botti, Marcus Niechciol, Alberto Daniel Supanitsky, Alexey Yushkov, Petr Schovánek, Pavel Horváth, Pedro Assis, Nataliia Borodai, Luis Lopes, Luis Nunez, Carla Bleve, Alberto Blanco, Katharine Mulrey, Antonella Castellina, Francesca Zuccarello, Felicia Carla Tiziana Barbato, Emanuele De Vito, Jose Alfredo Bellido Caceres, Fausto Guarino, Jeffrey Brack, Kai Daumiller, Dariusz Gora, Christian Sarmiento-Cano, Alessio Gorgi, Peter Biermann, Teresa Bister, LORENZO CACCIANIGA, Beatriz Garcia, Bruce Dawson, Alena Bakalova, MASSIMO MASTRODICASA, Edivaldo Moura Santos, Stijn Buitink, Bernardo Tomé, Ana Laura Müller, Mario BUSCEMI, Francesco Salamida, Johannes Hulsman, Henryk Wilczyński, Michael Unger, Ronald Cintra Shellard, Miguel Mostafa, Achille Nucita, Frederic Sarazin, Paul Mantsch, Ruben Conceição, Roger Clay, Lukáš Václavek, Giovanni Marsella, Markus Roth, Jakub Jurysek, Lorenzo Cazon, Eva Dos Santos, Corbin Covault, Francesco Fenu, Dalibor Nosek, Rossella Caruso, Alexandra Saftoiu, Tim Huege, Antonio CONDORELLI, Orazio Zapparrata, Jaime Alvarez-Muniz, Denise Boncioli, Guillermo Torralba Elipe, Martin Erdmann, Bruno Lazarotto Lago, Carlos José Todero Peixoto, Geraldina Golup, Jan Pękala, Maximilian Stadelmaier, Raul Sarmento, Enrique Varela, Antoine Letessier selvon, Vincenzo Rizi, Eleonora Guido, Pedro T. Abreu, Rafael Alves Batista, Arjen Van Vliet, and Jan Ebr

Subjects
Pierre Auger Observatory, Physics, Spectral index, 010308 nuclear & particles physics, Hadron, Flux, Cosmic ray, Astrophysics, 01 natural sciences, Flattening, 0103 physical sciences, 010306 general physics, Anisotropy, Zenith
Abstract

We report a measurement of the energy spectrum of cosmic rays for energies above 2.5×1018 eV based on 215,030 events recorded with zenith angles below 60°. A key feature of the work is that the estimates of the energies are independent of assumptions about the unknown hadronic physics or of the primary mass composition. The measurement is the most precise made hitherto with the accumulated exposure being so large that the measurements of the flux are dominated by systematic uncertainties except at energies above 5×1019 eV. The principal conclusions are(1) The flattening of the spectrum near 5×1018 eV, the so-called "ankle,"is confirmed.(2) The steepening of the spectrum at around 5×1019 eV is confirmed.(3) A new feature has been identified in the spectrum: in the region above the ankle the spectral index γ of the particle flux (∝E-γ) changes from 2.51±0.03 (stat)±0.05 (syst) to 3.05±0.05 (stat)±0.10 (syst) before changing sharply to 5.1±0.3 (stat)±0.1 (syst) above 5×1019 eV.(4) No evidence for any dependence of the spectrum on declination has been found other than a mild excess from the Southern Hemisphere that is consistent with the anisotropy observed above 8×1018 eV.

Published
2020

13. Features of the Energy Spectrum of Cosmic Rays above 2.5×1018 eV Using the Pierre Auger Observatory

Author

Jaroslaw Stasielak, Ana Martina Botti, Marcus Niechciol, Alberto Daniel Supanitsky, Alexey Yushkov, Petr Schovánek, Toshihiro Fujii, Pavel Horváth, Pedro Assis, Nataliia Borodai, Luis Lopes, Luis Nunez, Carla Bleve, Alberto Blanco, Katharine Mulrey, Antonella Castellina, Francesca Zuccarello, Felicia Carla Tiziana Barbato, Emanuele De Vito, Jose Alfredo Bellido Caceres, Fausto Guarino, Jeffrey Brack, Kai Daumiller, Dariusz Gora, Christian Sarmiento-Cano, Carola Dobrigkeit Chinellato, Alessio Gorgi, Peter Biermann, Teresa Bister, LORENZO CACCIANIGA, Beatriz Garcia, Bruce Dawson, Alena Bakalova, MASSIMO MASTRODICASA, Edivaldo Moura Santos, Stijn Buitink, Bernardo Tomé, Ana Laura Müller, Mario BUSCEMI, Francesco Salamida, Johannes Hulsman, Henryk Wilczyński, Michael Unger, Ronald Cintra Shellard, Miguel Mostafa, Achille Nucita, Frederic Sarazin, Paul Mantsch, Ruben Conceição, Roger Clay, Lukáš Václavek, Giovanni Marsella, Markus Roth, Jakub Jurysek, Lorenzo Cazon, Eva Dos Santos, Corbin Covault, Francesco Fenu, Dalibor Nosek, Rossella Caruso, Alexandra Saftoiu, Tim Huege, Antonio CONDORELLI, Orazio Zapparrata, Jaime Alvarez-Muniz, Denise Boncioli, Guillermo Torralba Elipe, Martin Erdmann, Bruno Lazarotto Lago, Carlos José Todero Peixoto, Geraldina Golup, Jan Pękala, Maximilian Stadelmaier, Raul Sarmento, Enrique Varela, Antoine Letessier selvon, Vincenzo Rizi, Eleonora Guido, Pedro T. Abreu, Rafael Alves Batista, Arjen Van Vliet, and Jan Ebr

Subjects
010308 nuclear & particles physics, 0103 physical sciences, General Physics and Astronomy, 010306 general physics, 01 natural sciences
Published
2020

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