E. O. Angüner
A5070948993- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Dark Matter and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Particle Detector Development and Performance
- Radio Astronomy Observations and Technology
- Neutrino Physics Research
- Pulsars and Gravitational Waves Research
- Particle physics theoretical and experimental studies
- Particle Accelerators and Free-Electron Lasers
- Solar and Space Plasma Dynamics
- Cosmology and Gravitation Theories
- Astronomical Observations and Instrumentation
- Galaxies: Formation, Evolution, Phenomena
- Radiation Detection and Scintillator Technologies
- Computational Physics and Python Applications
- Ionosphere and magnetosphere dynamics
- Stellar, planetary, and galactic studies
- Radiation Therapy and Dosimetry
- High-Energy Particle Collisions Research
- Astro and Planetary Science
- Medical Imaging Techniques and Applications
- Radioactivity and Radon Measurements
- Planetary Science and Exploration
- Opportunistic and Delay-Tolerant Networks
Scientific and Technological Research Council of Turkey
2023-2025
Centre National de la Recherche Scientifique
2018-2023
TU Dortmund University
2023
University of Łódź
2023
Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas
2023
University of Turku
2023
Niels Brock
2023
University of Copenhagen
2023
Main Astronomical Observatory
2023
Taras Shevchenko National University of Kyiv
2023
We present the results of most comprehensive survey Galactic plane in very high-energy (VHE) gamma-rays, including a public release sky maps, catalog VHE sources, and discovery 16 new sources gamma-rays. The High Energy Spectroscopic System (H.E.S.S.) (HGPS) was decade-long observation program carried out by H.E.S.S. I array Cherenkov telescopes Namibia from 2004 to 2013. observations amount nearly 2700 h data, covering at longitudes l = 250 deg 65 latitudes |b| < 3 deg. In addition...
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...
We provide an updated assessment of the power Cherenkov Telescope Array (CTA) to search for thermally produced dark matter at TeV scale, via associated gamma-ray signal from pair-annihilating particles in region around Galactic centre. find that CTA will open a new window discovery potential, significantly extending range robustly testable models given standard cuspy profile density distribution. Importantly, even cored profile, projected sensitivity be sufficient probe various...
Spectral lines are among the most powerful signatures for dark matter (DM) annihilation searches in very-high-energy $\gamma$-rays. The central region of Milky Way halo is one promising targets given its large amount DM and proximity to Earth. We report on a search monoenergetic spectral line from self-annihilations particles energy range 300 GeV 70 TeV using two-dimensional maximum likelihood method taking advantage both spatial features signal versus background. analysis makes use Galactic...
Supernova remnants exhibit shock fronts (shells) that can accelerate charged particles up to very high energies. In the past decade, measurements of a handful shell-type supernova in very-high-energy gamma rays have provided unique insights into acceleration process. Among those objects, RX$~$J1713.7-3946 (also known as G347.3-0.5) has largest surface brightness, allowing us perform most comprehensive study morphology and spatially resolved spectra any such gamma-ray source. Here we present...
The diffuse very high-energy (VHE, > 100 GeV) gamma-ray emission observed in the central 200 pc of Milky Way by H.E.S.S. was found to follow dense matter distribution Central Molecular Zone (CMZ) up a longitudinal distance about 130 Galactic Centre (GC), where flux rapidly decreases. Recent sensitive analysis revealed that cosmic-ray (CR) density profile drops with centre, making data compatible steady cosmic PeVatron at GC. In this paper, we extend obtain for first time detailed...
The central region of the Milky Way is one foremost locations to look for dark matter (DM) signatures. We report first results on a search DM particle annihilation signals using new observations from an unprecedented gamma-ray survey Galactic Center (GC) region, ${\it i.e.}$, Inner Galaxy Survey, at very high energies ($\gtrsim$ 100 GeV) performed with H.E.S.S. array five ground-based Cherenkov telescopes. No significant excess found in 2014-2020 dataset and profile likelihood ratio analysis...
Recurrent Novae are repeating thermonuclear explosions in the outer layers of white dwarfs, due to accretion fresh material from a binary companion. The shock generated by ejected slamming into companion star's wind, accelerates particles very-high-energies. We report very-high-energy (VHE, $\gtrsim100$\,GeV) gamma rays recurrent nova RS\,Ophiuchi up month after its 2021 outburst, using High Energy Stereoscopic System. VHE emission has similar temporal profile lower-energy GeV emission,...
Aims: We present a detailed view of the pulsar wind nebula (PWN) HESS J1825-137. aim to constrain mechanisms dominating particle transport within nebula, accounting for its anomalously large size and spectral characteristics. Methods: The is studied using deep exposure from over 12 years H.E.S.S. I operation, together with data II improving low energy sensitivity. Enhanced energy-dependent morphological spatially-resolved analyses probe Very High Energy (VHE, E > 0.1 TeV) gamma-ray...
The blazar Mrk 501 (z=0.034) was observed at very-high-energy (VHE, $E\gtrsim 100$~GeV) gamma-ray wavelengths during a bright flare on the night of 2014 June 23-24 (MJD 56832) with H.E.S.S. phase-II array Cherenkov telescopes. Data taken that by large zenith angle reveal an exceptional number photons multi-TeV energies, rapid flux variability and energy coverage extending significantly up to 20 TeV. This data set is used constrain Lorentz invariance violation (LIV) using two independent...
Very high-energy gamma-rays (VHE, E>100 GeV) propagating over cosmological distances can interact with the low-energy photons of extragalactic background light (EBL) and produce electron-positron pairs. The transparency universe to VHE is then directly related spectral energy distribution (SED) EBL. observation features in spectra sources allows EBL be measured, which otherwise very difficult determine. An EBL-model independent measurement SED H.E.S.S. array Cherenkov telescopes...
Shell-type supernova remnants (SNRs) are considered prime candidates for the acceleration of Galactic cosmic rays (CRs) up to knee CR spectrum at $\mathrm{E} \approx \mathrm{3}\times \mathrm{10}^\mathrm{15}$ eV. Our Milky Way galaxy hosts more than 350 SNRs discovered radio wavelengths and high energies, which 220 fall into H.E.S.S. Plane Survey (HGPS) region. Of those, only 50 coincident with a H.E.S.S source in 8 cases very high-energy (VHE) emission is firmly identified as an SNR. The GPS...
Dwarf spheroidal galaxy satellites of the Milky Way are prime targets for indirect detection dark matter with gamma rays due to their proximity, high content, and absence nonthermal emission processes. Recently, Dark Energy Survey (DES) revealed existence new ultrafaint dwarf galaxies in southern-hemisphere sky, therefore ideally located ground-based observations imaging atmospheric Cherenkov telescope array H.E.S.S. We present a search very-high-energy ($E\ensuremath{\gtrsim}100\text{...
Abstract We search for high-energy gamma-ray emission from the binary neutron star merger GW170817 with H.E.S.S. Imaging Air Cherenkov Telescopes. The observations presented here have been obtained starting only 5.3 hr after GW170817. target selection identified regions of high probability to find a counterpart gravitational-wave event. first these contained SSS17a that has in optical range several hours our observations. can therefore present data by ground-based pointing instrument on this...
Context. NGC 253 is one of only two starburst galaxies found to emit γ -rays from hundreds MeV multi-TeV energies. Accurate measurements the very-high-energy (VHE; E > 100 GeV) and high-energy (HE; 60 MeV) spectra are crucial study underlying particle accelerators, probe dominant emission mechanism(s) cosmic-ray interaction transport. Aims. The measurement VHE -ray published in 2012 by H.E.S.S. was limited large systematic uncertainties. Here, most up date spectrum investigated both HE...
A search for dark matter line-like signals was performed in the vicinity of Galactic Centre by H.E.S.S. experiment on observational data taken 2014. An unbinned likelihood analysis developed to improve sensitivity signals. The upgraded along with newer extend energy coverage previous measurement down 100 GeV. 18 h collected array allow one rule out at 95% CL presence a 130 GeV line (at $l = -1.5^{\circ}, b 0^{\circ}$ and profile centered this location) previously reported Fermi-LAT data....
Aims. We study gamma-ray emission from the shell-type supernova remnant (SNR) RX J0852.0$-$4622 to better characterize its spectral properties and distribution over SNR. Methods. The analysis of an extended High Energy Spectroscopic System (H.E.S.S.) data set at very high energies (E > 100 GeV) permits detailed studies, as well spatially resolved spectroscopy, morphology spectrum whole region. H.E.S.S. are combined with archival other wavebands interpreted in framework leptonic hadronic...
Studying the temporal variability of BL Lac objects at highest energies provides unique insights into extreme physical processes occurring in relativistic jets and vicinity super-massive black holes. To this end, long-term object PKS 2155−304 is analyzed high (HE, 100 MeV < E 300 GeV) very energy (VHE, > 200 γ-ray domain. Over course ~9 yr H.E.S.S. observations VHE light curve quiescent state consistent with a log-normal behavior. The well described by flicker noise (power-spectral-density...
Abstract Approximately one hundred sources of very-high-energy (VHE) gamma rays are known in the Milky Way, detected with a combination targeted observations and surveys. A survey entire Galactic Plane energy range from few tens GeV to TeV has been proposed as Key Science Project for upcoming Cherenkov Telescope Array Observatory (CTAO). This article presents status studies towards Survey (GPS). We build make publicly available sky model that combines data recent gamma-ray emitters...
An annihilation signal of dark matter is searched for from the central region Milky Way. Data acquired in dedicated on-off observations Galactic center with H.E.S.S. are analyzed this purpose. No significant found a total ∼9 h observations. Upper limits on velocity averaged cross section, ⟨σv⟩, particles masses range ∼300 GeV to ∼10 TeV derived. In contrast previous constraints derived region, that here apply also under assumption core constant density around Galaxy. Values ⟨σv⟩ larger than...
Aims. We report on the measurement and investigation of pulsed high-energy γ -ray emission from Vela pulsar, PSR B0833−45, based observations with largest telescope H.E.S.S., CT5, in monoscopic mode, data obtained Fermi -LAT. Methods. Data 40.3 h carried out H.E.S.S. II array 2013 to 2015 have been used. A dedicated very low-threshold event reconstruction analysis pipeline was developed achieve lowest possible energy threshold. Eight years -LAT were analysed also used as reference validate...