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Relentless multi-wavelength variability of Mrk 421 and Mrk 501
(2022)PoS: Proceedings of Science ~ Proceedings of 37th International Cosmic Ray ConferenceMrk 421 and Mrk 501 are two close, bright and well-studied high-synchrotron-peaked blazars, which feature bright and persistent GeV and TeV emission. We use the longest and densest dataset of unbiased observations of these two sources, obtained at TeV and GeV energies during five years with FACT and Fermi-LAT. To characterize the variability and derive constraints on the emission mechanism, we augment the dataset with contemporaneous ...Conference Paper -
Performance of the Cherenkov Telescope Array in the presence of clouds
(2022)PoS: Proceedings of Science ~ Proceedings of 37th International Cosmic Ray ConferenceThe Cherenkov Telescope Array (CTA) is the future ground-based observatory for gamma-ray astronomy at very high energies. The atmosphere is an integral part of every Cherenkov telescope. Different atmospheric conditions, such as clouds, can reduce the fraction of Cherenkov photons produced in air showers that reach ground-based telescopes, which may affect the performance. Decreased sensitivity of the telescopes may lead to misconstructed ...Conference Paper -
Prototype Open Event Reconstruction Pipeline for the Cherenkov Telescope Array
(2022)PoS: Proceedings of Science ~ Proceedings of 37th International Cosmic Ray ConferenceThe Cherenkov Telescope Array (CTA) is the next-generation gamma-ray observatory currently under construction. It will improve over the current generation of imaging atmospheric Cherenkov telescopes (IACTs) by a factor of five to ten in sensitivity and it will be able to observe the whole sky from a combination of two sites: a northern site in La Palma, Spain, and a southern one in Paranal, Chile. CTA will also be the first open gamma-ray ...Conference Paper -
Sensitivity of the Cherenkov Telescope Array to a dark matter signal from the Galactic centre
(2022)PoS: Proceedings of Science ~ Proceedings of 37th International Cosmic Ray ConferenceHigh-energy gamma rays are promising tools to constrain or reveal the nature of dark matter, in particular Weakly Interacting Massive Particles. Being well into its pre-construction phase, the Cherenkov Telescope Array (CTA) will soon probe the sky in the 20 GeV - 300 TeV energy range. Thanks to its improved energy and angular resolutions as well as significantly larger effective area when compared to the current generation of Cherenkov ...Conference Paper -
Exploring the population of Galactic very-high-energy γ-ray sources
(2022)PoS: Proceedings of Science ~ Proceedings of 37th International Cosmic Ray ConferenceAt very high energies (VHE), the emission of γ rays is dominated by discrete sources. Due to the limited resolution and sensitivity of current-generation instruments, only a small fraction of the total Galactic population of VHE γ-ray sources has been detected significantly. The larger part of the population can be expected to contribute as a diffuse signal alongside emission originating from propagating cosmic rays. Without quantifying ...Conference Paper -
Searching for very-high-energy electromagnetic counterparts to gravitational-wave events with the Cherenkov Telescope Array
(2022)PoS: Proceedings of Science ~ Proceedings of 37th International Cosmic Ray ConferenceThe detection of electromagnetic (EM) emission following the gravitational wave (GW) event GW170817 opened the era of multi-messenger astronomy with GWs and provided the first direct evidence that at least a fraction of binary neutron star (BNS) mergers are progenitors of short Gamma-Ray Bursts (GRBs). GRBs are also expected to emit very-high energy (VHE, > 100 GeV) photons, as proven by the recent MAGIC and H.E.S.S. observations. One of ...Conference Paper -
Multi-wavelength study of Mrk 421 during a TeV flare
(2022)PoS: Proceedings of Science ~ 37th International Cosmic Ray Conference (ICRC 2021)The blazar Mrk 421 shows frequent, short flares in the TeV energy regime. Due to the fast nature of such episodes, we often fail to obtain sufficient simultaneous information about flux variations in several energy bands. To overcome this lack of multi-wavelength (MWL) coverage, especially for the pre- and post-flare periods, we have set up a monitoring program with the FACT telescope (TeV energies) and the Neil Gehrels Swift Observatory ...Conference Paper -
Relentless multi-wavelength variability of Markarian 421 and Markarian 501
(2022)PoS: Proceedings of Science ~ 37th International Cosmic Ray Conference (ICRC 2021)Mrk 421 and Mrk 501 are two close bright and well-studied high-synchrotron-peaked blazars, which feature bright and persistent GeV and TeV emission. We use the longest and densest dataset of unbiased observations of these two sources, obtained at TeV and GeV energies during 5 years with the FACT telescope and Fermi-LAT. To characterize the variability and derive constraints on the emission mechanism, we augment the dataset with contemporaneous ...Conference Paper -
Statistical properties of flux variations in blazar light curves at GeV and TeV energies
(2022)PoS: Proceedings of Science ~ 37th International Cosmic Ray Conference (ICRC 2021)Despite numerous detections of individual flares, the physical origin of the rapid variability observed from blazars remains uncertain. Using Bayesian blocks and the Eisenstein-Hut HOP algorithm, we characterize flux variations of high significance in the γ-ray light curves of two samples of blazars. Daily binned long-term light curves of TeV-bright blazars observed with the First G-APD Cherenkov Telescope (FACT) are compared to those ...Conference Paper -
FACT - Database-based Analysis and Spectrum Calculations
(2022)PoS: Proceedings of Science ~ 37th International Cosmic Ray Conference (ICRC 2021)The First G-APD Cherenkov Telescope (FACT) is located at the Observatory Roque de los Muchachos on the Canary island La Palma. It uses the imaging air Cherenkov technique to detect gamma rays. With the help of silicon based photosensors in the camera, FACT is an ideal instrument to monitor a small sample of sources with a good time coverage. The automatic operation of the telescope allows an increase of the duty cycle of the instrument. ...Conference Paper