A5007250246- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Gamma-ray bursts and supernovae
- Particle Detector Development and Performance
- Neutrino Physics Research
- Radiation Detection and Scintillator Technologies
- Astrophysical Phenomena and Observations
- Particle physics theoretical and experimental studies
- Pulsars and Gravitational Waves Research
- Astronomical Observations and Instrumentation
- Particle Accelerators and Free-Electron Lasers
- Astronomy and Astrophysical Research
- Advanced Optical Sensing Technologies
- Cosmology and Gravitation Theories
- CCD and CMOS Imaging Sensors
- Atmospheric Ozone and Climate
- Adaptive optics and wavefront sensing
- Calibration and Measurement Techniques
- Galaxies: Formation, Evolution, Phenomena
- Computational Physics and Python Applications
- Photocathodes and Microchannel Plates
- Solar and Space Plasma Dynamics
- Medical Imaging Techniques and Applications
- Ionosphere and magnetosphere dynamics
GSI Helmholtz Centre for Heavy Ion Research
2024
ETH Zurich
2014-2024
University of Alaska Anchorage
2019-2023
Clark Atlanta University
2019-2023
RWTH Aachen University
2015-2023
Providence College
2019-2023
Lawrence Berkeley National Laboratory
2023
Southern University and Agricultural and Mechanical College
2019-2023
The University of Texas at Arlington
2019-2023
University of Würzburg
2009-2021
Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build next generation instrument, factor 5-10 improvement sensitivity 100 GeV 10 TeV range extension energies well below above TeV. will consist two arrays (one north, one south) for full sky coverage be operated as open observatory....
The blazar Mrk 501 was observed at energies above 0.10 TeV with the MAGIC Telescope from 2005 May through July. high sensitivity of instrument enabled determination flux and spectrum source on a night-by-night basis. Throughout our observational campaign, found to vary by an order magnitude. Intranight variability flux-doubling times down 2 minutes during two most active nights, namely, June 30 July 9. These are fastest variations ever in 501. ~20 minute long flare 9 showed indication 4 ± 1...
The atmospheric Cherenkov gamma-ray telescope MAGIC, designed for a low-energy threshold, has detected very-high-energy gamma rays from giant flare of the distant Quasi-Stellar Radio Source (in short: radio quasar) 3C 279, at distance more than 5 billion light-years (a redshift 0.536). No quasar been observed previously in radiation, and this is also most object emitting above 50 gigaelectron volts. Because high-energy may be stopped by interacting with diffuse background light universe,...
We present the first joint analysis of gamma-ray data from MAGIC Cherenkov telescopes and Fermi Large Area Telescope (LAT) to search for signals dark matter annihilation in dwarf satellite galaxies. combine 158 hours Segue 1 observations with 6-year 15 galaxies by -LAT. obtain limits on cross-section particle masses between 10 GeV 100 TeV—the widest mass range ever explored a single analysis. These improve previously published -LAT results up factor two at certain masses. Our new inclusive...
Microquasars are binary star systems with relativistic radio-emitting jets. They potential sources of cosmic rays and can be used to elucidate the physics We report detection variable gamma-ray emission above 100 gigaelectron volts from microquasar LS I 61 + 303. Six orbital cycles were recorded. Several detections occur at a similar phase, which suggests that is periodic. The strongest not observed when two stars closest one another, implying strong modulation or absorption processes.
Cosmic rays are atomic nuclei arriving from outer space that reach the highest energies observed in nature. Clues to their origin come studying distribution of arrival directions. Using 3 × 104 cosmic with above 8 1018 electron volts, recorded Pierre Auger Observatory a total exposure 76,800 km2 sr year, we determined existence anisotropy The anisotropy, detected at more than 5.2σ level significance, can be described by dipole an amplitude [Formula: see text] percent toward right ascension...
Very high energy (VHE) γ-ray emission from the flat spectrum radio quasar (FSRQ) PKS 1222+21 (4C 21.35, z = 0.432) was detected with MAGIC Cherenkov telescopes during a short observation (∼0.5 hr) performed on 2010 June 17. The detection coincides high-energy MeV/GeV activity measured by Large Area Telescope (LAT) board Fermi satellite. VHE extends about 70 GeV up to at least 400 and can be well described power-law dN/dE ∝ E−Γ photon index Γ 3.75 ± 0.27stat 0.2syst. averaged integral flux...
We present a combined fit of simple astrophysical model UHECR sources to both the energy spectrum and mass composition data measured by Pierre Auger Observatory. The has been performed for energies above 5 ⋅ 1018 eV, i.e. region all-particle so-called "ankle" feature. we adopted consists identical uniformly distributed in comoving volume, where nuclei are accelerated through rigidity-dependent mechanism. results suggest characterized relatively low maximum injection energies, hard spectra...
We report about very high energy (VHE) γ-ray observations of the Crab Nebula with MAGIC telescope. The flux from nebula was measured between 60 GeV and 9 TeV. spectrum can be described by a curved power law dF/dE = f0(E/300 GeV)[a+blog10(E/300 GeV)] normalization f0 (6.0 ± 0.2stat) × 10−10 cm−2 s−1 TeV−1, − 2.31 0.06stat, b 0.26 0.07stat. peak in spectral distribution is estimated at 77 35 GeV. Within observation time experimental resolution telescope, emission steady pointlike. emission's...
Abstract A new analysis of the data set from Pierre Auger Observatory provides evidence for anisotropy in arrival directions ultra-high-energy cosmic rays on an intermediate angular scale, which is indicative excess arrivals strong, nearby sources. The consist 5514 events above with zenith angles up to 80° recorded before 2017 April 30. Sky models have been created two distinct populations extragalactic gamma-ray emitters: active galactic nuclei second catalog hard Fermi -LAT sources (2FHL)...
The First G-APD Cherenkov Telescope (FACT) is designed to detect cosmic gamma-rays with energies from several hundred GeV up about 10 TeV using the Imaging Atmospheric Technique. In contrast former or existing telescopes, camera of FACT telescope comprised solid-state Geiger-mode Avalanche Photodiodes (G-APD) instead photomultiplier tubes for photo detection. It first full-scale device its kind employing this new technology. operated at Observatorio del Roque de los Muchachos (La Palma,...
Ultrahigh energy cosmic ray air showers probe particle physics at energies beyond the reach of accelerators. Here we introduce a new method to test hadronic interaction models without relying on absolute calibration, and apply it events with primary 6–16 EeV (ECM=110–170 TeV), whose longitudinal development lateral distribution were simultaneously measured by Pierre Auger Observatory. The average shower is 1.33±0.16 (1.61±0.21) times larger than predicted using leading LHC-tuned EPOS-LHC...
We report a measurement of the energy spectrum cosmic rays for energies above 2.5×1018 eV based on 215,030 events recorded with zenith angles below 60°. A key feature work is that estimates are independent assumptions about unknown hadronic physics or primary mass composition. The most precise made hitherto accumulated exposure being so large measurements flux dominated by systematic uncertainties except at 5×1019 eV. principal conclusions (1) flattening near 5×1018 eV, so-called "ankle,"...
Abstract In this work we present the interpretation of energy spectrum and mass composition data as measured by Pierre Auger Collaboration above 6 × 10 17 eV. We use an astrophysical model with two extragalactic source populations to hardening cosmic-ray flux at around 5 18 eV (the so-called “ankle” feature) a transition between these components. find our be well reproduced if sources ankle emit mixed hard low rigidity cutoff. The component below is required have very soft mix protons...
Bearing on the model for time-dependent metagalactic radiation field developed in first paper of this series, we compute gamma-ray attenuation due to pair production photon-photon scattering. Emphasis is effects varying star formation rate and fraction UV assumed escape from forming regions, latter being important mainly high-redshift sources. Conversely, investigate how can be measured creation cutoff as a function redshift, Fazio-Stecker relation. For three observed TeV-blazars (Mkn 501,...
We analyze the timing of photons observed by MAGIC telescope during a flare active galactic nucleus Mkn 501 for possible correlation with energy, as suggested some models quantum gravity (QG), which predict vacuum refractive index ≃1+(E/MQGn)n, n=1,2. Parametrizing delay between γ-rays different energies Δt=±τlE or Δt=±τqE2, we find τl=(0.030±0.012) s/GeV at 2.5-σ level, and τq=(3.71±2.57)×10−6 s/GeV2, respectively. use these results to establish lower limits MQG1>0.21×1018 GeV...
We report on the results from observations in very high energy band (VHE; Eγ ≥ 100 GeV) of black hole X-ray binary (BHXB) Cygnus X-1. The were performed with MAGIC telescope, for a total 40 hr during 26 nights, spanning period between 2006 June and November. Searches steady γ-ray signals yielded no positive result, upper limits to integral flux ranging 1% 2% Crab Nebula flux, depending energy, have been established. also analyzed each observation night independently, obtaining evidence at...
One fundamental question about pulsars concerns the mechanism of their pulsed electromagnetic emission. Measuring high-end region a pulsar's spectrum would shed light on this question. By developing new electronic trigger, we lowered threshold Major Atmospheric gamma-ray Imaging Cherenkov (MAGIC) telescope to 25 GeV. In configuration, detected gamma-rays from Crab pulsar that were greater than GeV, revealing relatively high cutoff energy in phase-averaged spectrum. This indicates emission...
We report the detection of a new source very high energy (VHE; Eγ ≥ 100 GeV) γ-ray emission located close to Galactic plane, MAGIC J0616+225, which is spatially coincident with supernova remnant IC 443. The observations were carried out telescope in periods 2005 December-2006 January and 2006 December-2007 January. Here we present results from this source, leading VHE signal statistical significance 5.7 σ 2006/2007 data measured differential flux consistent power law, described as dNγ/(dA dt...