1. Probing extreme environments with the Cherenkov Telescope ArrayC. Boisson, Anthony M. Brown, A. Burtovoi, M. Cerruti, M. Chernyakova, T. Hassan, J.-P. Lenain, Marina Manganaro, Serguei Vorobiov, Danilo Zavrtanik, 2021, other component parts Abstract: The physics of the non-thermal Universe provides information on the acceleration mechanisms in extreme environments, such as black holes and relativistic jets, neutron stars, supernovae or clusters of galaxies. In the presence of magnetic fields, particles can be accelerated towards relativistic energies. As a consequence, radiation along the entire electromagnetic spectrum can be observed, and extreme environments are also the most likely sources of multi-messenger emission. The most energetic part of the electromagnetic spectrum corresponds to the very-high-energy (VHE, E>100 GeV) gamma-ray regime, which can be extensively studied with ground based Imaging Atmospheric Cherenkov Telescopes (IACTs). The results obtained by the current generation of IACTs, such as H.E.S.S., MAGIC, and VERITAS, demonstrate the crucial importance of the VHE band in understanding the non-thermal emission of extreme environments in our Universe. In some objects, the energy output in gamma rays can even outshine the rest of the broadband spectrum. The Cherenkov Telescope Array (CTA) is the next generation of IACTs, which, with cutting edge technology and a strategic configuration of ~100 telescopes distributed in two observing sites, in the northern and southern hemispheres, will reach better sensitivity, angular and energy resolution, and broader energy coverage than currently operational IACTs. With CTA we can probe the most extreme environments and considerably boost our knowledge of the non-thermal Universe. Keywords: black holes, relativistic jets, neutron stars, supernovae, clusters of galaxies, particle acceleration mechanisms, very-high-energy gamma rays, Cherenkov Telescope Array Observatory Published in RUNG: 10.01.2025; Views: 582; Downloads: 4
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2. Bright blazar flares with CTAM. Cerruti, Saptashwa Bhattacharyya, Judit Pérez Romero, Samo Stanič, Veronika Vodeb, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, Miha Živec, 2023, published scientific conference contribution Abstract: The TeV extragalactic sky is dominated by blazars, radio-loud active galactic nuclei with a
relativistic jet pointing towards the Earth. Blazars show variability that can be quite exceptional
both in terms of flux (orders of magnitude of brightening) and time (down to the minute timescale).
This bright flaring activity contains key information on the physics of particle acceleration and
photon production in the emitting region, as well as the structure and physical properties of the
jet itself. The TeV band is accessed from the ground by Cherenkov telescopes that image the
pair cascade triggered by the interaction of the gamma ray with the Earth’s atmosphere. The
Cherenkov Telescope Array (CTA) represents the upcoming generation of imaging atmospheric
Cherenkov telescopes, with a significantly higher sensitivity and larger energy coverage with
respect to current instruments. It will thus provide us with unprecedented statistics on blazar
light-curves and spectra. In this contribution we present the results from realistic simulations of
CTA observations of bright blazar flares, taking as input state-of-the-art numerical simulations of
blazar emission models and including all relevant observational constraints. Keywords: active galactic nuclei, radio-loud AGN, blazars Published in RUNG: 15.09.2023; Views: 2812; Downloads: 6
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