Y. A. Gallant
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View article: Spectrum and extension of the inverse-Compton emission of the Crab Nebula from a combined Fermi-LAT and H.E.S.S. analysis
Spectrum and extension of the inverse-Compton emission of the Crab Nebula from a combined Fermi-LAT and H.E.S.S. analysis Open
The Crab Nebula is a unique laboratory for studying the acceleration of electrons and positrons through their non-thermal radiation. Observations of very-high-energy $\gamma$ rays from the Crab Nebula have provided important constraints fo…
View article: Unveiling extended gamma-ray emission around HESS J1813-178
Unveiling extended gamma-ray emission around HESS J1813-178 Open
Context. HESS J1813−178 is a very-high-energy γ-ray source spatially coincident with the young and energetic pulsar PSR J1813−1749and thought to be associated with its pulsar wind nebula (PWN). Recently, evidence for extended high-energy e…
View article: Detection of extended <i>γ</i>-ray emission around the Geminga pulsar with H.E.S.S.
Detection of extended <i>γ</i>-ray emission around the Geminga pulsar with H.E.S.S. Open
Geminga is an enigmatic radio-quiet γ -ray pulsar located at a mere 250 pc distance from Earth. Extended very-high-energy γ -ray emission around the pulsar was discovered by Milagro and later confirmed by HAWC, which are both water Cherenk…
View article: HESS J1809−193: A halo of escaped electrons around a pulsar wind nebula?
HESS J1809−193: A halo of escaped electrons around a pulsar wind nebula? Open
Context. HESS J1809−193 is an unassociated very-high-energy γ -ray source located on the Galactic plane. While it has been connected to the nebula of the energetic pulsar PSR J1809−1917, supernova remnants and molecular clouds present in t…
View article: A deep spectromorphological study of the<i>γ</i>-ray emission surrounding the young massive stellar cluster Westerlund 1
A deep spectromorphological study of the<i>γ</i>-ray emission surrounding the young massive stellar cluster Westerlund 1 Open
Context. Young massive stellar clusters are extreme environments and potentially provide the means for efficient particle acceleration. Indeed, they are increasingly considered as being responsible for a significant fraction of cosmic rays…
View article: Evidence for <i>γ</i>-ray emission from the remnant of Kepler’s supernova based on deep H.E.S.S. observations
Evidence for <i>γ</i>-ray emission from the remnant of Kepler’s supernova based on deep H.E.S.S. observations Open
Observations with imaging atmospheric Cherenkov telescopes (IACTs) have enhanced our knowledge of nearby supernova (SN) remnants with ages younger than 500 yr by establishing Cassiopeia A and the remnant of Tycho’s SN as very-high-energy (…
View article: Time-resolved hadronic particle acceleration in the recurrent nova RS Ophiuchi
Time-resolved hadronic particle acceleration in the recurrent nova RS Ophiuchi Open
Recurrent novae are repeating thermonuclear explosions in the outer layers of white dwarfs, due to the accretion of fresh material from a binary companion. The shock generated when ejected material slams into the companion star’s wind can …
View article: Searching for TeV Gamma-Ray Emission from SGR 1935+2154 during Its 2020 X-Ray and Radio Bursting Phase
Searching for TeV Gamma-Ray Emission from SGR 1935+2154 during Its 2020 X-Ray and Radio Bursting Phase Open
Magnetar hyperflares are the most plausible explanation for fast radio bursts (FRBs)—enigmatic powerful radio pulses with durations of several milliseconds and high brightness temperatures. The first observational evidence for this scenari…
View article: Search for enhanced TeV gamma-ray emission from Giant Molecular Clouds using H.E.S.S
Search for enhanced TeV gamma-ray emission from Giant Molecular Clouds using H.E.S.S Open
Cosmic Ray (CR) interactions with the dense gas inside Giant Molecular Clouds (GMCs) produce neutral pions, which in turn decay into gamma rays. Thus, the gamma ray emission from GMCs is a direct tracer of the cosmic ray density and the ma…
View article: Revealing x-ray and gamma ray temporal and spectral similarities in the GRB 190829A afterglow
Revealing x-ray and gamma ray temporal and spectral similarities in the GRB 190829A afterglow Open
An intrinsic gamma-ray burst afterglow Long gamma-ray bursts (GRBs) are emitted by relativistic jets generated during the collapse of a massive star in a distant galaxy. The GRB itself lasts only a few seconds but is followed by an aftergl…
View article: LMC N132D: A mature supernova remnant with a power-law gamma-ray spectrum extending beyond 8 TeV
LMC N132D: A mature supernova remnant with a power-law gamma-ray spectrum extending beyond 8 TeV Open
Context. Supernova remnants (SNRs) are commonly thought to be the dominant sources of Galactic cosmic rays up to the knee of the cosmic-ray spectrum at a few PeV. Imaging Atmospheric Cherenkov Telescopes have revealed young SNRs as very-hi…
View article: Probing the Magnetic Field in the GW170817 Outflow Using H.E.S.S. Observations
Probing the Magnetic Field in the GW170817 Outflow Using H.E.S.S. Observations Open
The detection of the first electromagnetic counterpart to the binary neutron star (BNS) merger remnant GW170817 established the connection between short γ -ray bursts and BNS mergers. It also confirmed the forging of heavy elements in the …
View article: Very high energy γ-ray emission from two blazars of unknown redshift and upper limits on their distance
Very high energy γ-ray emission from two blazars of unknown redshift and upper limits on their distance Open
We report on the detection of very high energy (VHE; E > 100 GeV) γ-ray emission from the BL Lac objects KUV 00311−1938 and PKS 1440−389 with the High Energy Stereoscopic System (H.E.S.S.). H.E.S.S. observations were accompanied or prec…
View article: Simultaneous observations of the blazar PKS 2155−304 from ultra-violet to TeV energies
Simultaneous observations of the blazar PKS 2155−304 from ultra-violet to TeV energies Open
Here we report the results of the first ever contemporaneous multi-wavelength observation campaign on the BL Lac object PKS 2155−304 involving Swift , NuSTAR , Fermi -LAT, and H.E.S.S. The use of these instruments allows us to cover a broa…
View article: H.E.S.S. detection of very high-energy <i>γ</i>-ray emission from the quasar PKS 0736+017
H.E.S.S. detection of very high-energy <i>γ</i>-ray emission from the quasar PKS 0736+017 Open
Context. Flat-spectrum radio-quasars (FSRQs) are rarely detected at very high energies ( E ≥ 100 GeV) due to their low-frequency-peaked spectral energy distributions. At present, only six FSRQs are known to emit very high-energy (VHE) phot…
View article: Study of Middle-aged Pulsar Wind Nebulae Showing Large Offsets Between their Pulsar and their VHE Gamma-ray Emission
Study of Middle-aged Pulsar Wind Nebulae Showing Large Offsets Between their Pulsar and their VHE Gamma-ray Emission Open
Pulsar wind nebulae (PWNe) are clouds of ultra-relativistic highly magnetised particles surrounding rapidly rotating neutron stars. Their emission can range from the radio band up to the very-high-energy (VHE) gamma-ray regime. We focus on…
View article: H.E.S.S. and<i>Suzaku</i>observations of the Vela X pulsar wind nebula
H.E.S.S. and<i>Suzaku</i>observations of the Vela X pulsar wind nebula Open
Context. Pulsar wind nebulae (PWNe) represent the most prominent population of Galactic very-high-energy gamma-ray sources and are thought to be an efficient source of leptonic cosmic rays. Vela X is a nearby middle-aged PWN, which shows b…
View article: H.E.S.S. observations of the flaring gravitationally lensed galaxy PKS 1830–211
H.E.S.S. observations of the flaring gravitationally lensed galaxy PKS 1830–211 Open
PKS 1830–211 is a known macrolensed quasar located at a redshift of z = 2.5. Its high-energy gamma-ray emission has been detected with the Fermi-Large Area Telescope (LAT) instrument and evidence for lensing was obtained by several authors…
View article: Particle transport within the pulsar wind nebula HESS J1825–137
Particle transport within the pulsar wind nebula HESS J1825–137 Open
Context. We present a detailed view of the pulsar wind nebula (PWN) HESS J1825–137. We aim to constrain the mechanisms dominating the particle transport within the nebula, accounting for its anomalously large size and spectral characterist…
View article: Study of the Very High Energy emission of the Pulsar Wind Nebula in MSH 15-5 2
Study of the Very High Energy emission of the Pulsar Wind Nebula in MSH 15-5 2 Open
International audience
View article: VHE γ-ray discovery and multi-wavelength study of the blazar 1ES 2322-409
VHE γ-ray discovery and multi-wavelength study of the blazar 1ES 2322-409 Open
A hotspot at a position compatible with the BL Lac object 1ES 2322−409 was serendipitously detected with H.E.S.S. during observations performed in 2004 and 2006 on the blazar PKS 2316−423. Additional data on 1ES 2322−409 were taken in 2011…
View article: Search for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>γ</mml:mi></mml:math>-Ray Line Signals from Dark Matter Annihilations in the Inner Galactic Halo from 10 Years of Observations with H.E.S.S.
Search for -Ray Line Signals from Dark Matter Annihilations in the Inner Galactic Halo from 10 Years of Observations with H.E.S.S. Open
Spectral lines are among the most powerful signatures for dark matter (DM) annihilation searches in very-high-energy γ rays. The central region of the Milky Way halo is one of the most promising targets given its large amount of DM and pro…
View article: H.E.S.S. discovery of very high energy γ-ray emission from PKS 0625−354
H.E.S.S. discovery of very high energy γ-ray emission from PKS 0625−354 Open
PKS 0625−354 (z = 0.055) was observed with the four High Energy Stereoscopic System (H.E.S.S.) telescopes in 2012 during 5.5 h. The source was detected above an energy threshold of 200 GeV at a significance level of 6.1σ. No significant va…
View article: HESS J1741−302: a hidden accelerator in the Galactic plane
HESS J1741−302: a hidden accelerator in the Galactic plane Open
The H.E.S.S. Collaboration has discovered a new very high energy (VHE, E > 0.1 TeV) γ -ray source, HESS J1741−302, located in the Galactic plane. Despite several attempts to constrain its nature, no plausible counterpart has been found so …
View article: TeV Gamma-Ray Observations of the Binary Neutron Star Merger GW170817 with H.E.S.S.
TeV Gamma-Ray Observations of the Binary Neutron Star Merger GW170817 with H.E.S.S. Open
We search for high-energy gamma-ray emission from the binary neutron star merger GW170817 with the H.E.S.S. Imaging Air Cherenkov Telescopes. The observations presented here have been obtained starting only 5.3 hr after GW170817. The H.E.S…
View article: Contributions of the High Energy Stereoscopic System (H.E.S.S.) to the 35th International Cosmic Ray Conference (ICRC), Busan, Korea
Contributions of the High Energy Stereoscopic System (H.E.S.S.) to the 35th International Cosmic Ray Conference (ICRC), Busan, Korea Open
Index of H.E.S.S. conference proceedings to the 35th ICRC, Busan, Korea