Publications (66)
Search for photon line-like signatures from Dark Matter annihilations with H.E.S.S
H. E. S. S. Collaboration, :, A. Abramowski +201
Gamma-ray line signatures can be expected in the very-high-energy (VHE; E_γ> 100 GeV) domain due to self-annihilation or decay of dark matter (DM) particles in space. Such a signa…
Constraints on axionlike particles with H.E.S.S. from the irregularity of the PKS 2155-304 energy spectrum
H. E. S. S. Collaboration, A. Abramowski, F. Acero +211
Axionlike particles (ALPs) are hypothetical light (sub-eV) bosons predicted in some extensions of the Standard Model of particle physics. In astrophysical environments comprising h…
H.E.S.S. constraints on Dark Matter annihilations towards the Sculptor and Carina Dwarf Galaxies
HESS Collaboration, A. Abramowski, F. Acero +192
The Sculptor and Carina Dwarf spheroidal galaxies were observed with the H.E.S.S. Cherenkov telescope array between January 2008 and December 2009. The data sets consist of a total…
Probing the gamma-ray emission from HESS J1834-087 using H.E.S.S. and Fermi LAT observations
The H. E. S. S. Collaboration, :, A. Abramowski +228
Previous observations with HESS have revealed the existence of an extended very-high-energy (VHE; E>100 GeV) gamma-ray source, HESS J1834-087, coincident with the SNR W41. The orig…
H.E.S.S. Observations of the Crab during its March 2013 GeV Gamma-Ray Flare
H. E. S. S. Collaboration, A. Abramowski, F. Aharonian +217
Context. On March 4, 2013, the Fermi-LAT and AGILE reported a flare from the direction of the Crab Nebula in which the high-energy (HE; E > 100 MeV) flux was six times above its qu…
Measurement of the Crab Flux Above 60 GeV with the CELESTE Cherenkov Telescope
M. De Naurois, J. Holder, R. Bazer-Bachi +29
We have converted the former solar electrical plant THEMIS (French Pyrenees) into an atmospheric Cherenkov detector called CELESTE, which records gamma rays above 30 GeV (7E24 Hz).…
HESS J1943+213: a candidate extreme BL Lacertae object
H. E. S. S. Collaboration, :, A. Abramowski +200
We report on a newly detected point-like source, HESS J1943+213 located in the Galactic plane. This source coincides with an unidentified hard X-ray source IGR J19443+2117, which w…
Discovery of very high energy gamma-ray emission from the BL Lac object PKS 0301-243 with H.E.S.S
H. E. S. S. Collaboration, A. Abramowski, F. Acero +211
The active galactic nucleus PKS 0301-243 (z=0.266) is a high-synchrotron-peaked BL Lac object that is detected at high energies (HE, 100 MeV < E < 100 GeV) by Fermi/LAT. This paper…
Prototype Tests for the CELESTE Solar Array Gamma--Ray Telescope
B. Giebels, R. Bazer-Bachi, H. Bergeret +24
The CELESTE experiment will be an Atmospheric Cherenkov detector designed to bridge the gap in energy sensitivity between current satellite and ground-based gamma-ray telescopes, 2…
Discovery of VHE γ-ray emission and multi-wavelength observations of the BL Lac object 1RXS J101015.9-311909
HESS Collaboration, A. Abramowski, F. Acero +191
1RXS J101015.9-311909 is a galaxy located at a redshift of z=0.14 hosting an active nucleus belonging to the class of bright BL Lac objects. Observations at high (HE, E > 100 MeV)…
Temporal and spectral gamma-ray properties of Mkn421 above 250 GeV from CAT observations between 1996 and 2000
F. Piron, A. Djannati-Atai, M. Punch +22
The gamma-ray emission above 250 GeV from the BL Lac object Markarian 421 was observed by the CAT Cherenkov imaging telescope between December, 1996, and June, 2000. In 1998, the s…
Search for a Dark Matter annihilation signal from the Galactic Center halo with H.E.S.S
H. E. S. S. Collaboration, :, A. Abramowski +193
A search for a very-high-energy (VHE; >= 100 GeV) gamma-ray signal from self-annihilating particle Dark Matter (DM) is performed towards a region of projected distance r ~ 45-150 p…
Revisiting the Westerlund 2 Field with the H.E.S.S. Telescope Array
The HESS Collaboration, A. Abramowski, F. Acero +194
Aims. Previous observations with the H.E.S.S. telescope array revealed the existence of extended very-high-energy (VHE; E>100 GeV) γ-ray emission, HESS J1023-575, coincident with…
A new SNR with TeV shell-type morphology: HESS J1731-347
HESS Collaboration, A. Abramowski, F. Acero +195
The recent discovery of the radio shell-type supernova remnant (SNR), G353.6-0.7, in spatial coincidence with the unidentified TeV source HESS J1731-347 has motivated further obser…
The 2012 flare of PG 1553+113 seen with H.E.S.S. and Fermi-LAT
A. Abramowski, F. Aharonian, F. Ait Benkhali +224
Very high energy (VHE, 100 GeV) -ray flaring activity of the high-frequency peaked BL Lac object \pg\ has been detected by the \hess\ telescopes. The flux of the source inc…
Discovery of extended VHE γ-ray emission from the vicinity of the young massive stellar cluster Westerlund 1
HESS Collaboration, A. Abramowski, F. Acero +198
Results obtained in very-high-energy (VHE; E > 100 GeV) γ-ray observations performed with the H.E.S.S. telescope array are used to investigate particle acceleration processes in t…
Simultaneous multi-wavelength campaign on PKS 2005-489 in a high state
The H. E. S. S. Collaboration, the Fermi LAT Collaboration, : +345
The high-frequency peaked BL Lac object PKS 2005-489 was the target of a multi-wavelength campaign with simultaneous observations in the TeV gamma-ray (H.E.S.S.), GeV gamma-ray (Fe…
Long-term monitoring of PKS 2155304 with ATOM and H.E.S.S.: investigation of optical/-ray correlations in different spectral states
A. Abramowski, F. Aharonian, F. Ait Benkhali +225
In this paper we report on the analysis of all the available optical and very high-energy -ray (200 GeV) data for the BL Lac object PKS 2155304, collected simultaneously…
First detection of VHE gamma-rays from SN 1006 by H.E.S.S
HESS Collaboration, F. Acero, F. Aharonian +175
Recent theoretical predictions of the lowest very high energy (VHE) luminosity of SN 1006 are only a factor 5 below the previously published H.E.S.S. upper limit, thus motivating f…
Search for TeV Gamma-ray Emission from GRB 100621A, an extremely bright GRB in X-rays, with H.E.S.S
H. E. S. S. Collaboration, A. Abramowski, F. Aharonian +213
The long gamma-ray burst (GRB) 100621A, at the time the brightest X-ray transient ever detected by Swift-XRT in the keV range, has been observed with the H.E.S.S…
The exceptionally powerful TeV gamma-ray emitters in the Large Magellanic Cloud
H. E. S. S. Collaboration, :, A. Abramowski +226
The Large Magellanic Cloud, a satellite galaxy of the Milky Way, has been observed with the High Energy Stereoscopic System (H.E.S.S.) above an energy of 100 billion electron volts…
Discovery of the VHE gamma-ray source HESS J1832-093 in the vicinity of SNR G22.7-0.2
H. E. S. S. Collaboration, :, A. Abramowski +218
The region around the supernova remnant (SNR) W41 contains several TeV sources and has prompted the H.E.S.S. Collaboration to perform deep observations of this field of view. This…
H.E.S.S. Observations of the Binary System PSR B1259-63/LS 2883 around the 2010/2011 Periastron Passage
H. E. S. S. Collaboration, :, A. Abramowski +203
Aim. In this paper we present very high energy (VHE; E>100 GeV) data from the γ-ray binary system PSR B1259-63/LS 2883 taken around its periastron passage (15th of December 2010)…
Spectral analysis and interpretation of the γ-ray emission from the Starburst galaxy NGC 253
H. E. S. S. Collaboration, A. Abramowski, F. Acero +192
Very-high-energy (VHE; E >100 GeV) and high-energy (HE; 100 MeV < E < 100 GeV) data from γ-ray observations performed with the H.E.S.S. telescope array and the Fermi-LAT instrumen…
H.E.S.S. discovery of VHE gamma-rays from the quasar PKS 1510-089
H. E. S. S. Collaboration, A. Abramowski, F. Acero +204
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 the optical and GeV bands, to search for ve…
Performances of the CAT imaging telescope and some preliminary results on Mkn 180 and the Crab
A. Barrau, R. Bazer-Bachi, H. Cabot +33
The CAT imaging telesope, which uses the Atmospheric Cherenkov Technique to observe TeV gamma-ray sources, has been operating since September 1996. Located in southern France, it f…
Search for Dark Matter Annihilation Signals from the Fornax Galaxy Cluster with H.E.S.S
HESS Collaboration, A. Abramowski, F. Acero +195
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 for very-high-energy (VHE, E>100 GeV) gamm…
Flux upper limits for 47 AGN observed with H.E.S.S. in 2004-2011
H. E. S. S. Collaboration, A. Abramowski, F. Aharonian +217
About 40% of the observation time of the High Energy Stereoscopic System (H.E.S.S.) is dedicated to studying active galactic nuclei (AGN), with the aim of increasing the sample of…
A multiwavelength view of the flaring state of PKS 2155-304 in 2006
HESS Collaboration, A. Abramowski, F. Acero +208
Multiwavelength (MWL) observations of the blazar PKS 2155-304 during two weeks in July and August 2006, the period when two exceptional flares at very high energies (VHE, E>= 100 G…
Discovery of VHE emission towards the Carina arm region with the H.E.S.S. telescope array: HESS J1018-589
HESS Collaboration, A. Abramowski, F. Acero +195
The observational coverage with HESS of the Carina region in VHE gamma-rays benefits from deep exposure (40 h) of the neighboring open cluster Westerlund 2. The observations have r…
Observation of the Crab Nebula Gamma-Ray Emission Above 220 Gev by the Cat Cherenkov Imaging Telescope
A. Barrau, R. Bazer-Bachi, H. Cabot +33
The CAT imaging telescope, recently built on the site of the former solar plant Themis (French Pyrenees), observed gamma-rays from the Crab nebula from October 1996 to March 1997.…
HESS J1640-465 - an exceptionally luminous TeV gamma-ray supernova remnant
H. E. S. S. Collaboration, A. Abramowski, F. Aharonian +218
The results of follow-up observations of the TeV gamma-ray source HESSJ 1640-465 from 2004 to 2011 with the High Energy Stereoscopic System (H.E.S.S.) are reported in this work. Th…
Probing the extent of the non-thermal emission from the Vela X region at TeV energies with H.E.S.S
A. Abramowski, F. Acero, F. Aharonian +196
Vela X is a region of extended radio emission in the western part of the Vela constellation: one of the nearest pulsar wind nebulae (PWNe), and associated with the energetic Vela p…
Discovery of high and very high-energy emission from the BL Lac object SHBL J001355.9-185406
H. E. S. S. Collaboration, :, A. Abramowski +210
The detection of the high-frequency peaked BL Lac object (HBL) SHBL J001355.9-185406 (=0.095) at high (HE; 100 MeVE300 GeV) and very high-energy (VHE; )…
Discovery of VHE gamma-rays from the BL Lac object PKS 0548-322
H. E. S. S. collaboration, :, F. Aharonian +168
PKS 0548-322 (z=0.069) is a ``high-frequency-peaked'' BL Lac object and a candidate very high energy (VHE, E>100 GeV) gamma-ray emitter, due to its high X-ray and radio flux. Obser…
H.E.S.S. observations of the Carina nebula and its enigmatic colliding wind binary Eta Carinae
HESS Collaboration, A. Abramowski, F. Acero +191
The massive binary system Eta Carinae and the surrounding HII complex, the Carina Nebula, are potential particle acceleration sites from which very-high-energy (VHE; E > 100 GeV) Î…
H.E.S.S. observations of the globular clusters NGC 6388 and M 15 and search for a Dark Matter signal
HESS Collaboration, A. Abramowski, F. Acero +195
Observations of the globular clusters NGC 6388 and M 15 were carried out by the H.E.S.S. array of Cherenkov telescopes for a live time of 27.2 and 15.2 hours respectively. No gamma…
Search for Extended γ-ray Emission around AGN with H.E.S.S. and Fermi-LAT
H. E. S. S. Collaboration, A. Abramowski, F. Aharonian +218
Context: Very-high-energy (VHE; E>100 GeV) γ-ray emission from blazars inevitably gives rise to electron-positron pair production through the interaction of these γ-rays with the…
A new analysis method for very high definition Imaging Atmospheric Cherenkov Telescopes as applied to the CAT telescope
S. Le Bohec, B. Degrange, M. Punch +33
A new method of shower-image analysis is presented which appears very powerful as applied to those Cherenkov Imaging Telescopes with very high definition imaging capability. It pro…
Very-high-energy gamma-ray emission from the direction of the Galactic globular cluster Terzan 5
HESS Collaboration, A. Abramowski, F. Acero +194
The H.E.S.S. very-high-energy (VHE, E > 0.1 TeV) gamma-ray telescope system has discovered a new source, HESS J1747-248. The measured integral flux is (1.2 +/- 0.3) \times 10^-12 c…
H.E.S.S and Fermi-LAT discovery of gamma rays from the blazar 1ES 1312-423
H. E. S. S. Collaboration, A. Abramowski, F. Acero +214
A deep observation campaign carried out by the High Energy Stereoscopic System (H.E.S.S.) on Centaurus A enabled the discovery of gamma rays from the blazar 1ES 1312-423, two degre…
Discovery of gamma-ray emission from the extragalactic pulsar wind nebula N157B with the High Energy Stereoscopic System
HESS Collaboration, A. Abramowski, F. Acero +195
We present the significant detection of the first extragalactic pulsar wind nebula (PWN) detected in gamma rays, N157B, located in the large Magellanic Cloud (LMC). Pulsars with hi…
Detection of the BL Lac object 1ES1426+428 in the Very High Energy gamma-ray band by the CAT Telescope from 1998-2000
A. Djannati-Atai, B. Khelifi, S. Vorobiov +14
The BL Lac Object 1ES 1426+428, at a red-shift of z=0.129, has been monitored by the CAT telescope from February 1998 to June 2000. The accumulation of 26 hours of observations sho…
Search for Lorentz Invariance breaking with a likelihood fit of the PKS 2155-304 flare data taken on MJD 53944
HESS Collaboration, A. Abramowski, F. Acero +193
Several models of Quantum Gravity predict Lorentz Symmetry breaking at energy scales approaching the Planck scale (10^{19} GeV). With present photon data from the observations of d…
Identification of HESS J1303-631 as a Pulsar Wind Nebula through gamma-ray, X-ray and radio observations
The H. E. S. S. Collaboration, :, A. Abramowski +196
The previously unidentified very high-energy (VHE; E > 100 GeV) γ-ray source HESS J1303-631, discovered in 2004, is re-examined including new data from the H.E.S.S. Cherenkov tele…
The CAT Imaging Telescope
A. Barrau, R. Bazer-Bachi, H. Cabot +33
The VHE gamma-ray imaging telescope CAT started taking data in October 1996. Located at the Themis solar site in southern France, it features a 17.7 m^2 Davies-Cotton mirror equipp…
Measurement of the extragalactic background light imprint on the spectra of the brightest blazars observed with H.E.S.S
H. E. S. S. Collaboration, :, A. Abramowski +195
The extragalactic background light (EBL) is the diffuse radiation with the second highest energy density in the Universe after the cosmic microwave background. The aim of this stud…
HESS J1818-154, a new composite supernova remnant discovered in TeV gamma rays and X-rays
H. E. S. S. Collaboration, A. Abramowski, F. Aharonian +217
Composite supernova remnants (SNRs) constitute a small subclass of the remnants of massive stellar explosions where non-thermal radiation is observed from both the expanding shell-…
Multi-wavelength Observations of H 2356-309
HESS Collaboration, A. Abramowski, F. Acero +184
AIMS: The properties of the broad-band emission from the high-frequency peaked BL Lac H 2356-309 (z=0.165) are investigated. METHODS: Very High Energy (VHE; E > 100 GeV) observatio…
Detection of Vhe Gamma-Rays from MRK 501 with the Cat Imaging Telescope
A. Barrau, R. Bazer-Bachi, H. Cabot +33
The CAT imaging telescope on the site on the former solar plant Themis has been observing gamma-rays from Mrk501 above 220 GeV in March and April 1997. This source is shown to be h…
Discovery and follow-up studies of the extended, off-plane, VHE gamma-ray source HESS J1507-622
H. E. S. S. Collaboration, F. Acero, F. Aharonian +167
Context: The detection of gamma-rays in the very-high-energy (VHE) range (100 GeV-100 TeV) offers the possibility of studying the parent population of ultrarelativistic particles f…
The CAT Imaging Telescope for Very-High-Energy Gamma-Ray Astronomy
A. Barrau, R. Bazer-Bachi, E. Beyer +49
The CAT (Cherenkov Array at Themis) imaging telescope, equipped with a very-high-definition camera (546 fast phototubes with 0.12 degrees spacing surrounded by 54 larger tubes in t…
CTA contributions to the 33rd International Cosmic Ray Conference (ICRC2013)
The CTA Consortium, :, O. Abril +1102
Compilation of CTA contributions to the proceedings of the 33rd International Cosmic Ray Conference (ICRC2013), which took place in 2-9 July, 2013, in Rio de Janeiro, Brazil
Discovery of TeV gamma-ray emission from PKS 0447-439 and derivation of an upper limit on its redshift
H. E. S. S. Collaboration, :, A. Abramowski +204
Very high-energy gamma-ray emission from PKS 0447-439 was detected with the H.E.S.S. Cherenkov telescope array in December 2009. This blazar is one of the brightest extragalactic o…
Constraints on the gamma-ray emission from the cluster-scale AGN outburst in the Hydra A galaxy cluster
HESS Collaboration, A. Abramowski, F. Acero +193
In some galaxy clusters powerful AGN have blown bubbles with cluster scale extent into the ambient medium. The main pressure support of these bubbles is not known to date, but cosm…
The 2010 very high energy gamma-ray flare & 10 years of multi-wavelength observations of M 87
The H. E. S. S. Collaboration, :, A. Abramowski +442
Abridged: The giant radio galaxy M 87 with its proximity, famous jet, and very massive black hole provides a unique opportunity to investigate the origin of very high energy (VHE;…
TeV γ-ray observations of the young synchrotron-dominated SNRs G1.9+0.3 and G330.2+1.0 with H.E.S.S
H. E. S. S. Collaboration, A. Abramowski, F. Aharonian +217
The non-thermal nature of the X-ray emission from the shell-type supernova remnants (SNRs) G1.9+0.3 and G330.2+1.0 is an indication of intense particle acceleration in the shock fr…
VHE gamma-ray emission of PKS 2155-304: spectral and temporal variability
HESS Collaboration, A. Abramowski, F. Acero +185
Observations of very high energy gamma-rays from blazars provide information about acceleration mechanisms occurring in their innermost regions. Studies of variability in these obj…
Spectrum and Variability of Mrk501 as observed by the CAT Imaging Telescope
A. Barrau, R. Bazer-Bachi, H. Cabot +33
The CAT Imaging Telescope has observed the BL Lac object Markarian 501 between March and August 1997. We report here on the variability over this time including several large flare…
Discovery of the source HESS J1356-645 associated with the young and energetic PSR J1357-6429
HESS Collaboration, A. Abramowski, F. Acero +195
Several newly discovered very-high-energy (VHE; E > 100 GeV) gamma-ray sources in the Galaxy are thought to be associated with energetic pulsars. Among them, middle-aged (> 1E+4 yr…
Detection of very-high-energy gamma-ray emission from the vicinity of PSR B1706-44 and G343.1-2.3 with H.E.S.S
H. E. S. S. Collaboration, :, A. Abramowski +198
The gamma-ray pulsar PSR B1706-44 and the adjacent supernova remnant (SNR) candidate G343.1-2.3 were observed by H.E.S.S. during a dedicated observation campaign in 2007. As a resu…
Search for dark matter annihilation signatures in H.E.S.S. observations of Dwarf Spheroidal Galaxies
H. E. S. S. Collaboration, :, A. Abramowski +229
Dwarf spheroidal galaxies of the Local Group are close satellites of the Milky Way characterized by a large mass-to-light ratio and are not expected to be the site of non-thermal h…
Long-term TeV and X-ray Observations of the Gamma-ray Binary HESS J0632+057
VERITAS Collaboration, E. Aliu, S. Archambault +297
HESS J0632+057 is the only gamma-ray binary known so far whose position in the sky allows observations with ground-based observatories both in the northern and southern hemispheres…
Very High Energy Gamma-ray spectral properties of Mrk 501 from CAT Cerenkov telescope observations in 1997
A. Djannati-Atai, F. Piron, A. Barrau +31
The BL Lac object Mrk 501 went into a very high state of activity during 1997, both in VHE gamma-rays and X-rays. We present here results from observations at energies above 250 Ge…
Search for Very-high-energy γ-ray emission from Galactic globular clusters with H.E.S.S
H. E. S. S. Collaboration, :, A. Abramowski +203
Globular clusters (GCs) are established emitters of high-energy (HE, 100 MeV<E<100 GeV) γ-ray radiation which could originate from the cumulative emission of the numerous millisec…
Discovery of hard-spectrum γ-ray emission from the BL Lac object 1ES 0414+009
The HESS Collaboration, A. Abramowski, F. Acero +199
1ES 0414+009 (z = 0.287) is a distant high-frequency-peaked BL Lac object, and has long been considered a likely emitter of very-high energy (VHE, E>100 GeV) gamma-rays due to its…