J. G. Giesbrecht Paiva
A5073998858- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Gamma-ray bursts and supernovae
- Dark Matter and Cosmic Phenomena
- Particle Accelerators and Free-Electron Lasers
- Particle physics theoretical and experimental studies
- Particle Detector Development and Performance
- Cosmology and Gravitation Theories
- Astrophysical Phenomena and Observations
- Neutrino Physics Research
- Astronomical Observations and Instrumentation
- Astronomy and Astrophysical Research
- Noncommutative and Quantum Gravity Theories
- Terahertz technology and applications
- Pulsars and Gravitational Waves Research
- Laser Design and Applications
- Stellar, planetary, and galactic studies
- Gyrotron and Vacuum Electronics Research
- Precipitation Measurement and Analysis
- Mental Health Treatment and Access
- Advanced X-ray and CT Imaging
- Radioactivity and Radon Measurements
- Computational Physics and Python Applications
- Radio Wave Propagation Studies
- COVID-19 and Mental Health
Centro Brasileiro de Pesquisas Físicas
2022-2024
Foundation for Research and Technology Hellas
2023
University of Siena
2023
Boston University
2023
Max Planck Institute for Physics
2023
University of Osijek
2023
TU Dortmund University
2023
University of Rijeka
2023
Turku Centre for Computer Science
2023
University of Turku
2023
ABSTRACT In recent years, a new generation of optical intensity interferometers has emerged, leveraging the existing infrastructure Imaging Atmospheric Cherenkov Telescopes (IACTs). The MAGIC telescopes host MAGIC-SII system (Stellar Intensity Interferometer), implemented to investigate feasibility and potential this technique on IACTs. After first successful measurements in 2019, was upgraded now features real-time, dead-time-free, 4-channel, GPU-based correlator. These hardware...
Linelike features in TeV γ rays constitute a "smoking gun" for TeV-scale particle dark matter and new physics. Probing the Galactic Center region with ground-based Cherenkov telescopes enables search spectral immediate association dense reservoir at sensitivity out of reach satellite γ-ray detectors, direct detection collider experiments. We report on 223 hours observations MAGIC stereoscopic telescope system reaching energies up to 100 TeV. improved lines high using large-zenith-angle novel...
Abstract We study the broadband emission of Mrk 501 using multiwavelength observations from 2017 to 2020 performed with a multitude instruments, involving, among others, MAGIC, Fermi's Large Area Telescope (LAT), NuSTAR, Swift, GASP-WEBT, and Owens Valley Radio Observatory. showed an extremely low activity, which may help unravel its baseline emission. Nonetheless, significant flux variations are detected at all wave bands, highest occurring X-rays very-high-energy (VHE) γ -rays. A...
Context. Certain types of supernova remnants (SNRs) in our Galaxy are assumed to be PeVatrons, capable accelerating cosmic rays (CRs) ~ PeV energies. However, conclusive observational evidence for this has not yet been found. The SNR G106.3+2.7, detected at 1–100 TeV energies by different γ-ray facilities, is one the most promising PeVatron candidates. This a cometary shape, which can divided into head and tail region with physical conditions. 100 emission produced identified because limited...
Mrk 421 was in its most active state around early 2010, which led to the highest TeV gamma-ray flux ever recorded from any galactic nuclei. We aim characterize multiwavelength behavior during this exceptional year for 421, and evaluate whether it is consistent with picture derived data other less years. investigated period November 5, 2009, (MJD 55140) until July 3, 55380) extensive coverage very-high-energy (VHE; E$\,>\,$100$\,$GeV) gamma rays radio MAGIC, VERITAS, Fermi-LAT, RXTE, Swift,...
Context. The supernova remnant (SNR) W44 and its surroundings are a prime target for studying the acceleration of cosmic rays (CRs). Several previous studies established an extended gamma-ray emission that is set apart from radio shell W44. This thought to originate escaped high-energy CRs interact with surrounding dense molecular cloud complex. Aims. We present detailed analysis Fermi-LAT data emphasis on spatial spectral properties surroundings. also report results observations performed...
The BL Lacertae object VER J0521+211 underwent a notable flaring episode in February 2020. A short-term monitoring campaign, led by the MAGIC (Major Atmospheric Gamma Imaging Cherenkov) collaboration, covering wide energy range from radio to very high-energy (VHE, 100 GeV $<$ E TeV) gamma rays was organised study its evolution. These observations resulted consistent detection of source over six consecutive nights VHE gamma-ray domain. Combining these nightly with an extensive set...
Mrk,421 was in its most active state around early 2010, which led to the highest TeV gamma-ray flux ever recorded from any galactic nuclei (AGN). We aim characterize multiwavelength behavior during this exceptional year for Mrk,421, and evaluate whether it is consistent with picture derived data other less years. investigated period November 5, 2009, (MJD 55140) until July 3, 55380) extensive coverage very-high-energy (VHE; E$,>,$100$,$GeV) gamma rays radio MAGIC, VERITAS Fermi -LAT RXTE...
Blazars exhibit strong variability across the entire electromagnetic spectrum, including periods of high-flux states commonly known as flares. The physical mechanisms in blazar jets responsible for flares remain poorly understood to date. Our aim is better understand emission during using X-ray polarimetry and broadband observations from archetypical TeV Mrk 421, which can be studied with higher accuracy than other blazars that are dimmer and/or located farther away. We a flaring activity...
Abstract Massive brane fluctuations, called branons, behave as weakly interacting massive particles, which is one of the most favored class candidates to fulfill role dark matter (DM), an elusive kind beyond Standard Model. We present a multi-target search in dwarf spheroidal galaxies for branon DM annihilation signatures with total exposure 354 hours ground-based gamma-ray telescope system MAGIC. This led constraining limits on sub-TeV and multi-TeV mass range. Our stringent limit...
Among the blazars whose emission has been detected up to very high-energy (VHE; $100 GeV < E 100 TeV$) γ rays, intermediate synchrotron-peaked BL Lacs (IBLs) are quite rare. The IBL (z = 0.117) exhibited intense flaring activity in 2020. Detailed characterization of source from radio γ-ray energies was achieved with quasi-simultaneous observations, which led first-time detection VHE MAGIC telescopes. In this work, we present a comprehensive multiwavelength (MWL) view specific focus on...
Aims. We present the first multiwavelength study of Mrk 501 that contains simultaneous very-high-energy (VHE) γ -ray observations and X-ray polarization measurements from Imaging Polarimetry Explorer (IXPE). Methods. used radio-to-VHE data a campaign carried out between March 1, 2022, July 19, 2022 (MJD 59639 to MJD 59779). The were performed by MAGIC, Fermi -LAT, NuSTAR , Swift (XRT UVOT), several other instruments cover optical radio bands complement IXPE pointings. characterized dynamics...
Abstract The Lorentz Invariance Violation (LIV), a proposed consequence of certain quantum gravity (QG) scenarios, could instigate an energy-dependent group velocity for ultra-relativistic particles. This energy dependence, although suppressed by the massive QG scale E_QG, expected to be on level Planck 1.22 × 10 19 GeV, is potentially detectable in astrophysical observations. In this scenario, cosmological distances traversed photons act as amplifier effect. By leveraging observation...
Gamma-ray bursts (GRBs) are explosive transient events occurring at cosmological distances, releasing a large amount of energy as electromagnetic radiation over several bands. We report the detection long GRB~201216C by MAGIC telescopes. The source is located $z=1.1$ and thus it farthest one detected very high energies. emission above \SI{70}{\GeV} modelled together with multi-wavelength data within synchrotron synchrotron-self Compton (SSC) scenario. find that SSC can explain broadband well...
Aims. We have performed the first broadband study of Mrk 421 from radio to TeV gamma rays with simultaneous measurements X-ray polarization IXPE. Methods. The data were collected as part an extensive multiwavelength campaign carried out between May and June 2022 using MAGIC, Fermi -LAT, NuSTAR , XMM-Newton Swift several optical telescopes complement IXPE data. Results. During exposures, measured 0.2–1 flux was close quiescent state ranged 25% 50% Crab Nebula without intra-night variability....
PG 1553+113 is one of the few blazars with a convincing quasi-periodic emission in gamma-ray band. The source also very high-energy (VHE; >100 GeV) emitter. To better understand its properties and identify underlying physical processes driving variability, MAGIC Collaboration initiated multiyear, multiwavelength monitoring campaign 2015 involving OVRO 40-m Medicina radio telescopes, REM, KVA, Swift Fermi satellites, WEBT network. analysis presented this paper uses data until 2017 focuses on...
Context. The BL Lac object 1ES 0647+250 is one of the few distant γ -ray emitting blazars detected at very high energies (VHEs; ≳100 GeV) during a non-flaring state. It was with MAGIC telescopes period low activity in years 2009−2011 as well three flaring activities 2014, 2019, and 2020, highest VHE flux last epoch. An extensive multi-instrument data set collected part several coordinated observing campaigns over these years. Aims. We aim to characterise long-term multi-band variability...
MAXI J1820+070 is a low-mass X-ray binary with black hole as compact object. This underwent an exceptionally bright outburst from March to October 2018, showing evidence of non-thermal particle population through its radio emission during this whole period. The combined results 59.5 hours observations the H.E.S.S., MAGIC and VERITAS experiments at energies above 200 GeV are presented, together Fermi-LAT data between 0.1 500 GeV, multiwavelength X-rays. Gamma-ray not detected J1820+070, but...
The BL Lac 1ES 2344+514 is known for temporary extreme properties (e.g., a shift of the synchrotron SED peak energy $\nu_{synch,p}$ above 1keV). While those states were so far observed only during high flux levels, additional multi-year observing campaigns are required to achieve coherent picture. Here, we report longest investigation source from radio VHE performed far, focusing on systematic characterisation intermittent states. our results confirm that typically exhibits...
Axion-like particles (ALPs) are pseudo-Nambu-Goldstone bosons that emerge in various theories beyond the standard model. These can interact with high-energy photons external magnetic fields, influencing observed gamma-ray spectrum. This study analyzes 41.3 hrs of observational data from Perseus Galaxy Cluster collected MAGIC telescopes. We focused on spectra radio galaxy center cluster: NGC 1275. By modeling field surrounding this target, we searched for spectral indications ALP presence....
The supernova remnant (SNR) and its surroundings are a prime target for studying the acceleration of cosmic rays (CRs). Several previous studies established an extended gamma-ray emission that is set apart from radio shell This thought to originate escaped high-energy CRs interact with surrounding dense molecular cloud complex. We present detailed analysis data emphasis on spatial spectral properties surroundings. also report results observations performed MAGIC telescopes northwestern...
An extraordinary flare from blazar Mrk 421 was recorded on the night of April 24, 2014, by Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescopes at very high energy (VHE) 100 GeV up to 10 TeV. Several quantum-gravity models indicate that photon group velocity in vacuum may be dependent, known as in-vacuum dispersion. Violation Lorentz Invariance (LIV) this kind can lead an observable effect time flight VHE photons cosmic origin. Observations fast and distant phenomena, such 421, are...
We present the first multi-wavelength study of Mrk 501 including very-high-energy (VHE) gamma-ray observations simultaneous to X-ray polarization measurements from Imaging Polarimetry Explorer (IXPE). use radio-to-VHE data a campaign organized between 2022-03-01 and 2022-07-19. The were performed by MAGIC, Fermi-LAT, NuSTAR, Swift (XRT UVOT), several instruments covering optical radio bands. During IXPE pointings, VHE state is close average behavior with 0.2-1 TeV flux 20%-50% emission Crab...