A. Barnacka
A5055616996- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Dark Matter and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Radio Astronomy Observations and Technology
- Pulsars and Gravitational Waves Research
- Particle Detector Development and Performance
- Cosmology and Gravitation Theories
- Neutrino Physics Research
- Particle physics theoretical and experimental studies
- Astronomical Observations and Instrumentation
- Galaxies: Formation, Evolution, Phenomena
- Particle Accelerators and Free-Electron Lasers
- Astronomy and Astrophysical Research
- Relativity and Gravitational Theory
- Stellar, planetary, and galactic studies
- Radiation Detection and Scintillator Technologies
- History and Developments in Astronomy
- Phonocardiography and Auscultation Techniques
- Astrophysics and Star Formation Studies
- Non-Invasive Vital Sign Monitoring
- Photocathodes and Microchannel Plates
- Superconducting and THz Device Technology
- Atomic and Subatomic Physics Research
- Vascular Anomalies and Treatments
Center for Astrophysics Harvard & Smithsonian
2014-2023
Jagiellonian University
2014-2023
Scripps Clinic
2023
Smithsonian Astrophysical Observatory
2021-2022
Institut de Recherche sur les Lois Fondamentales de l'Univers
2010-2021
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2010-2021
CEA Paris-Saclay
2010-2021
University of Tübingen
2021
Université Paris-Saclay
2021
Friedrich-Alexander-Universität Erlangen-Nürnberg
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....
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...
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...
The abundance of primordial black holes is currently significantly constrained in a wide range masses. weakest limits are established for the small mass objects where intensity associated physical phenomenon provides challenge current experiments. We used gamma-ray bursts with known redshifts detected by Fermi Gamma-ray Burst Monitor (GBM) to search femtolensing effects caused compact objects. lack detection GBM data new evidence that ${10}^{17}--{10}^{20}\text{ }\text{ }\mathrm{g}$ do not...
The extragalactic background light (EBL) is the diffuse radiation with second highest energy density in Universe after cosmic microwave background. aim of this study measurement imprint EBL opacity to γ-rays on spectra brightest sources detected High Energy Stereoscopic System (H.E.S.S.). originality method lies joint fit optical depth and intrinsic sources, assuming smoothness. Analysis a total ~105γ-ray events enables detection an signature at 8.8σ level constitutes first using very-high...
The giant radio galaxy M 87 with its proximity (16 Mpc), famous jet, and very massive black hole ((3 − 6) × 109 M☉) provides a unique opportunity to investigate the origin of high energy (VHE; E > 100 GeV) γ-ray emission generated in relativistic outflows surroundings supermassive holes. has been established as VHE emitter since 2006. displays strong variability on timescales short day. In this paper, results from joint monitoring campaign by MAGIC VERITAS instruments 2010 are reported....
Axionlike particles (ALPs) are hypothetical light (sub-eV) bosons predicted in some extensions of the Standard Model particle physics. In astrophysical environments comprising high-energy gamma rays and turbulent magnetic fields, existence ALPs can modify energy spectrum for a sufficiently large coupling between photons. This modification would take form an irregular behavior limited range. Data from H.E.S.S. observations distant BL Lac object PKS 2155-304 (z = 0.116) used to derive upper...
We present coordinated multiwavelength observations of the bright, nearby BL Lac object Mrk 421 taken in 2013 January-March, involving GASP-WEBT, Swift, NuSTAR, Fermi-LAT, MAGIC, VERITAS, and other collaborations instruments, providing data from radio to very-high-energy (VHE) gamma-ray bands. NuSTAR yielded previously unattainable sensitivity 3-79 keV range, revealing that spectrum softens when source is dimmer until X-ray spectral shape saturates into a steep power law with photon index...
Dwarf spheroidal galaxies of the Local Group are close satellites Milky Way characterized by a large mass-to-light ratio and not expected to be site non-thermal high-energy gamma-ray emission or intense star formation. Therefore they amongst most promising candidates for indirect dark matter searches. During last years High Energy Stereoscopic System (H.E.S.S.) imaging atmospheric Cherenkov telescopes observed five these dwarf more than 140 hours in total, searching TeV from annihilation...
Diffuse $\ensuremath{\gamma}$-ray emission is the most prominent observable signature of celestial cosmic-ray interactions at high energies. While already being investigated GeV energies over several decades, assessments diffuse TeV remain sparse. After completion systematic survey inner Galaxy, H.E.S.S. experiment in a prime position to observe large-scale Data Galactic Plane Survey are regions off known sources. Corresponding flux measurements were made an extensive grid locations....
Results obtained in very-high-energy (VHE; E > 100 GeV) \gamma-ray observations performed with the H.E.S.S. telescope array are used to investigate particle acceleration processes vicinity of young massive stellar cluster Westerlund 1 (Wd 1). Imaging Cherenkov light from induced cascades Earth's atmosphere is search for VHE \gamma\ rays region around Wd 1. Possible catalogued counterparts searched and discussed terms morphology energetics source. The detection degree-scale extended source...
The quasar PKS 1510-089 (z=0.361) was observed with the H.E.S.S. array of imaging atmospheric Cherenkov telescopes during high states in optical and GeV bands, to search for very energy (VHE, defined as E >= 0.1 TeV) emission. VHE \gamma-rays were detected a statistical significance 9.2 standard deviations 15.8 hours data taken March April 2009. A integral flux I(0.15 TeV < 1.0 = (1.0 +- 0.2 (stat) (sys) x 10^{-11} cm^{-2}s^{-1} is measured. best-fit power law has photon index \Gamma=5.4 0.7...
Outbursts from gamma-ray quasars provide insights on the relativistic jets of active galactic nuclei and constraints diffuse radiation fields that fill universe. The detection significant emission above 100 GeV a distant quasar would show some radiated gamma-rays escape pair-production interactions with low-energy photons, be it extragalactic background light (EBL), or near supermassive black hole lying at jet's base. VERITAS detected up to ∼200 PKS 1441+25 (z = 0.939) during 2015 April,...
The Fornax galaxy cluster was observed with the High Energy Stereoscopic System (H.E.S.S.) for a total live time of 14.5 hours, searching very-high-energy (VHE, E>100 GeV) gamma-rays from dark matter (DM) annihilation. No significant signal found in searches point-like and extended emissions. Using several models DM density distribution, upper limits on velocity-weighted annihilation cross-section <sigma v> as function particle mass are derived. Constraints derived different models, such...
The recent discovery of the radio shell-type supernova remnant (SNR), G353.6-0.7, in spatial coincidence with unidentified TeV source HESS J1731-347 has motivated further observations High Energy Stereoscopic System (H.E.S.S.) Cherenkov telescope array to test a possible association gamma-ray emission SNR. With total 59 hours observation, representing about four times initial exposure available paper J1731-347, morphology is investigated and compared morphology. An estimate distance derived...
Very high energy (VHE, E > 100 GeV) γ-ray flaring activity of the high-frequency peaked BL Lac object PG 1553+113 has been detected by H.E.S.S. telescopes. The flux source increased a factor 3 during nights 2012 April 26 and 27 with respect to archival measurements hint intra-night variability. No counterpart this event in Fermi-Large Area Telescope data. This pattern is consistent VHE being caused injection ultrarelativistic particles, emitting γ-rays at highest energies. dataset offers...
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{...
Multiwavelength (MWL) observations of the blazar PKS 2155-304 during two weeks in July and August 2006, period when exceptional flares at very high energies (VHE, E>= 100 GeV) occurred, provide a detailed picture evolution its emission. The complete data set from this campaign is presented, including VHE gamma-rays (H.E.S.S.), X-rays (RXTE, CHANDRA, SWIFT XRT), optical (SWIFT UVOT, Bronberg, Watcher, ROTSE), radio band (NRT, HartRAO, ATCA). Optical light curves 2004 to 2008 are compared...
Vela X is a region of extended radio emission in the western part constellation: one nearest pulsar wind nebulae (PWNe), and associated with energetic (PSR B0833-45). Extended very-high-energy (VHE) $\gamma$-ray (HESS $\mathrm{J0835\mhyphen 455}$) was discovered using H.E.S.S. experiment 2004. The VHE found to be coincident X-ray ${\it ROSAT}$ above 1.5 keV (the so-called \textit{Vela cocoon}): filamentary structure extending southwest from centre X. A deeper observation entire nebula...
About 40% of the observation time High Energy Stereoscopic System (H.E.S.S.) is dedicated to studying active galactic nuclei (AGN), with aim increasing sample known extragalactic very-high-energy (VHE, E>100 GeV) sources and constraining physical processes at play in potential emitters. H.E.S.S. observations AGN, spanning a period from April 2004 December 2011, are investigated constrain their gamma-ray fluxes. Only 47 without significant excess detected position targets presented. Upper...