A5090466928- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Dark Matter and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Radio Astronomy Observations and Technology
- Neutrino Physics Research
- Particle Detector Development and Performance
- Cosmology and Gravitation Theories
- Particle physics theoretical and experimental studies
- Astronomical Observations and Instrumentation
- Stellar, planetary, and galactic studies
- Particle Accelerators and Free-Electron Lasers
- Astrophysics and Star Formation Studies
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Solar and Space Plasma Dynamics
- Astro and Planetary Science
- Nuclear Physics and Applications
- Radiation Detection and Scintillator Technologies
- Noncommutative and Quantum Gravity Theories
- Geophysics and Gravity Measurements
- History and Developments in Astronomy
- Atomic and Subatomic Physics Research
- Radioactive Decay and Measurement Techniques
Tokai University
2025
University of the Witwatersrand
2015-2024
Institut de Recherche sur les Lois Fondamentales de l'Univers
2008-2023
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2005-2023
CEA Paris-Saclay
2008-2023
ETH Zurich
2023
University of Würzburg
2023
Deutsches Elektronen-Synchrotron DESY
2016-2023
Linnaeus University
2023
Centre National de la Recherche Scientifique
2007-2023
The Crab nebula was observed with the H.E.S.S. stereoscopic Cherenkov-telescope array between October 2003 and January 2005 for a total of 22.9 hours (after data quality selection). Observations were made three operational telescopes in late complete 4 telescope - February 2004 2005. observations are discussed used as an example to detail flux spectral analysis procedures H.E.S.S., evaluate systematic uncertainties measurements. spectrum gamma-rays from source calculated on run-by-run...
The high-frequency peaked BL Lac PKS 2155-304 at redshift z = 0.116 is a well-known VHE (>100 GeV) γ-ray emitter. Since 2002 its flux has been monitored using the H.E.S.S. stereoscopic array of imaging atmospheric Cerenkov telescopes in Namibia. During 2006 July dark period, average was measured to be more than 10 times typical values observed from object. This article focuses solely on an extreme outburst detected early hours 28 (MJD 53,944). during this I(>200 (1.72 ± 0.05stat 0.34syst) ×...
The very large collection area of ground-based gamma-ray telescopes gives them a substantial advantage over balloon or satellite based instruments in the detection very-high-energy (>600 GeV) cosmic-ray electrons. Here we present electron spectrum derived from data taken with High Energy Stereoscopic System (H.E.S.S.) imaging atmospheric Cherenkov telescopes. In this measurement, first type, are able to extend measurement beyond range accessible direct measurements. We find evidence for...
We report on a survey of the inner part Galactic Plane in very high energy gamma-rays, with H.E.S.S. Cherenkov telescope system. The between +-30deg longitude and +-3deg latitude relative to Centre was observed 500 pointings for total 230 hours, reaching an average flux sensitivity 2% Crab Nebula at energies above 200 GeV. Fourteen previously unknown sources were detected significance level greater than 4 sigma after accounting all trials involved search. Initial results eight most...
The measurement of an excess in the cosmic-ray electron spectrum between 300 and 800 GeV by ATIC experiment has - together with PAMELA detection a rise positron fraction up to 100 motivated many interpretations terms dark matter scenarios; alternative explanations assume nearby source like pulsar or supernova remnant. Here we present H.E.S.S. starting at 340 GeV. While overall flux measured is consistent data within statistical systematic errors, exclude pronounced peak as suggested for...
We report the detection of a point-like source very high energy (VHE) gamma-rays coincident within 1' Sgr A*, obtained with H.E.S.S. array Cherenkov telescopes. The exhibit power-law spectrum spectral index -2.2 +/- 0.09 0.15 and flux above 165 GeV threshold (1.82 0.22) * 10^-7 m^-2 s^-1. measured differ substantially from recent results reported in particular by CANGAROO collaboration.
A search for a very-high-energy (VHE; ≥100 GeV) γ-ray signal from self-annihilating particle dark matter (DM) is performed towards region of projected distance r∼45-150 pc the Galactic center. The background-subtracted spectrum measured with High Energy Stereoscopic System (H.E.S.S.) instrument in energy range between 300 GeV and 30 TeV shows no hint residual flux. Assuming conventional Navarro-Frenk-White Einasto density profiles, limits are derived on velocity-weighted annihilation cross...
Gamma-ray line signatures can be expected in the very-high-energy (${E}_{\ensuremath{\gamma}}>100\text{ }\text{ }\mathrm{GeV}$) domain due to self-annihilation or decay of dark matter (DM) particles space. Such a signal would readily distinguishable from astrophysical $\ensuremath{\gamma}$-ray sources that most cases produce continuous spectra span over several orders magnitude energy. Using data collected with H.E.S.S. instrument, upper limits on linelike emission are obtained energy range...
The Cherenkov Telescopes Array (CTA) is planned as the future instrument for very-high-energy (VHE) gamma-ray astronomy with a wide energy range of four orders magnitude and an improvement in sensitivity compared to current instruments about order magnitude. Monte Carlo simulations are crucial tool design CTA. ultimate goal these find most cost-effective solution given physics goals thus or find, cost, best suited different types targets Apart from uncertain component cost estimates, main...
The long gamma-ray burst (GRB) 100621A, at the time brightest X-ray transient ever detected by Swift-XRT in $0.3\textrm{--}10$ keV range, has been observed with H.E.S.S. imaging air Cherenkov telescope array, sensitive to gamma radiation very-high-energy (VHE, $>100$ GeV) regime. Due its relatively small redshift of $z\sim0.5$, favourable position southern sky and short follow-up ($<700 \rm{s}$ after satellite trigger) observations, this GRB could be within sensitivity reach instrument....
Gamma-ray bursts (GRBs), which are bright flashes of gamma rays from extragalactic sources followed by fading afterglow emission, associated with stellar core collapse events. We report the detection very-high-energy (VHE) GRB 190829A, between 4 and 56 hours after trigger, using High Energy Stereoscopic System (H.E.S.S.). The low luminosity redshift 190829A reduce both internal external absorption, allowing determination its intrinsic energy spectrum. Between energies 0.18 3.3 tera-electron...
SS 433 is a microquasar, stellar binary system that launches collimated relativistic jets. We observed in gamma rays using the High Energy Stereoscopic System (H.E.S.S.) and found an energy-dependent shift apparent position of gamma-ray emission from parsec-scale These observations trace energetic electron population indicate inverse Compton scattering mechanism rays. Our modeling morphology constrains location particle acceleration requires abrupt deceleration jet flow. infer presence...
We report the discovery of very-high-energy (VHE) γ-ray emission binary system PSR B1259-63/SS 2883 a radio pulsar orbiting massive, luminous Be star in highly eccentric orbit.The observations around 2004 periastron passage were performed with four 13 m Cherenkov telescopes HESS experiment, recently installed Namibia and full operation since December 2003.Between February June 2004, signal from was detected total significance above 13σ.The flux found to vary significantly on timescales days...
X-ray binaries are composed of a normal star in orbit around neutron or stellar-mass black hole. Radio and x-ray observations have led to the presumption that some called microquasars behave as scaled-down active galactic nuclei. Microquasars resolved radio emission is thought arise from relativistic outflow akin nuclei jets, which particles can be accelerated large energies. Very high energy gamma-rays produced by interactions these been observed several Using High Energy Stereoscopic...
The detection of fast variations the tera-electron volt (TeV) (10(12) eV) gamma-ray flux, on time scales days, from nearby radio galaxy M87 is reported. These are about 10 times as those observed in any other wave band and imply a very compact emission region with dimension similar to Schwarzschild radius central black hole. We thus can exclude several sites processes production. observations confirm that TeV gamma rays emitted by extragalactic sources than blazars, where jets not...
We present deep H.E.S.S. observations of the supernova remnant (SNR) RX J1713.7-3946. Combining data three years - from 2003 to 2005 we obtain significantly increased statistics and energy coverage as compared earlier & 2004 results. The are analysed separately for different years. Very good agreement gamma-ray morphology differential spectra is found when comparing combined image reveals J1713.7-3946 with unprecedented precision. An angular resolution 0.06 deg achieved, revealing...
We present results from deep observations of the Galactic shell-type supernova remnant (SNR) RX J1713.7-3946 (also known as G347.3-0.5) conducted with complete H.E.S.S. array in 2004. Detailed morphological and spatially resolved spectral studies reveal very-high-energy (VHE -- Energies E > 100 GeV) gamma-ray aspects this object unprecedented precision. Since is first in-depth analysis an extended VHE source, we a thorough discussion our methodology investigations possible sources...
Very high energy gamma-rays probe the long-standing mystery of origin cosmic rays. Produced in interactions accelerated particles astrophysical objects, they can be used to image particle accelerators. A first sensitive survey inner part Milky Way with High Energy Stereoscopic System (H.E.S.S.) reveals a population eight previously unknown firmly detected sources very gamma-rays. At least two have no known radio or X-ray counterpart and may representative new class `dark' nucleonic ray sources.
We observed the W28 field (for ~40 h) at Very High Energy (VHE) gamma-ray energies (E>0.1 TeV) with H.E.S.S. Cherenkov telescopes. A reanalysis of EGRET E>100 MeV data was also undertaken. Results from NANTEN 4m telescope Galactic plane survey and other CO observations have been used to study molecular clouds. discovered VHE emission (HESSJ1801-233) coincident northeastern boundary W28, a complex sources (HESSJ1800-240A, B C) ~0.5 deg south in disc. The differential photon spectra are well...
Aims. LS 5039 is a High Mass X-ray Binary (HMXRB) comprising compact object in an eccentric 3.9 day orbit around massive O6.5V star. Observations at energies above 0.1 TeV (1011 eV) by the Energy Stereoscopic System (HESS) 2004 revealed that source of Very (VHE) γ-rays and hence, able to accelerate particles multi-TeV energies. Deeper observations HESS were carried out 2005 effort probe further high energy astrophysics taking place. In particular, we have searched for orbital modulation VHE...
Aims.To investigate the very high energy (VHE: >100 GeV) γ-ray emission from high-frequency peaked BL Lac 1ES 0229+200.