252 citations · 1.4k across the 16 of their papers we have counts for
16 papers
Observations of 54 Active Galactic Nuclei with the HEGRA System of Cherenkov Telescopes
The HEGRA Collaboration, F. Aharonian, A. Akhperjanian +1
A sample of 54 selected Active Galactic Nuclei (AGN) has been observed with the HEGRA stereoscopic system of Cherenkov Telescopes between 1996 and 2002 in the TeV energy regime. Th…
The Technical Performance of the HEGRA System of Imaging Air Cherenkov Telescopes
G. Puehlhofer, O. Bolz, N. Goetting +1
Between early 1997 and late 2002, the HEGRA collaboration operated a stereoscopic system of 4 (later 5) imaging atmospheric Cherenkov telescopes. In this paper we present the calib…
Is the Giant Radio Galaxy M87 a TeV Gamma-Ray Emitter?
HEGRA Collaboration, F. Aharonian, A. Akhperjanian +1
For the first time an excess of photons above an energy threshold of 730 GeV from the giant radio galaxy M87 has been measured at a significance level above 4 sigma. The data have…
A search for TeV gamma-ray emission from SNRs, pulsars and unidentified GeV sources in the Galactic plane in the longitude range between -2 deg and 85 deg
HEGRA-Collaboration, F. A. Aharonian
Using the HEGRA system of imaging atmospheric Cherenkov telescopes, one quarter of the Galactic plane (-2 deg < l < 85 deg) was surveyed for TeV gamma-ray emission from point sourc…
An unidentified TeV source in the vicinity of Cygnus OB2
F. A. Aharonian, A. Akhperjanian, M. Beilicke +2
Deep observation (~113 hrs) of the Cygnus region at TeV energies using the HEGRA stereoscopic system of air Cerenkov telescopes has serendipitously revealed a signal positionally i…
Variations of the TeV energy spectrum at different flux levels of Mkn 421 observed with the HEGRA system of Cherenkov telescopes
HEGRA Collaboration, F. Aharonian
The nearby BL Lacertae (BL Lac) object Markarian~421 (Mkn~421) at a red shift z=0.031 was observed to undergo strong TeV Gamma-ray outbursts in the observational periods from Decem…
A study of Tycho's SNR at TeV energies with the HEGRA CT-System
F. A. Aharonian, A. G. Akhperjanian, J. A. Barrio +1
Tycho's supernova remnant (SNR) was observed during 1997 and 1998 with the HEGRA Cherenkov Telescope System in a search for gamma-ray emission at energies above ~1 TeV. An analysis…
Evidence for TeV gamma ray emission from Cassiopeia A
HEGRA Collaboration, F. Aharonian
232 hours of data were accumulated from 1997 to 1999, using the HEGRA Stereoscopic Cherenkov Telescope System to observe the supernova remnant Cassiopeia A. TeV gamma ray emission…
Reanalysis of the high energy cutoff of the 1997 Mkn 501 TeV energy spectrum
HEGRA Collaboration, F. Aharonian
Data taken with the HEGRA system of imaging atmospheric Cherenkov telescopes during the 1997 flares of Mkn 501 are reanalyzed using an algorithm providing improved energy resolutio…
The TeV Energy Spectrum of Mkn 501 Measured with the Stereoscopic Telescope System of HEGRA during 1998 and 1999
The HEGRA Collaboration, F. Aharonian, A. Akhperjanian +1
During 1997, the BL Lac object Mkn 501 went into an extraordinary state of high X-ray and TeV gamma-ray activity, lasting more than 6 months. In this paper we report on the TeV emi…
Rejection of the hypothesis that Markarian 501 TeV photons are pure Bose-Einstein condensates
The HEGRA Collaboration, F. Aharonian, A. Akhperjanian +1
The energy spectrum of the Blazar type galaxy Markarian 501 (Mrk 501) as measured by the High-Energy-Gamma-Ray Astronomy (HEGRA) air Cerenkov telescopes extends beyond 16 TeV and c…
The Energy Spectrum of TeV Gamma-Rays from the Crab Nebula as measured by the HEGRA system of imaging air Cherenkov telescopes
F. Aharonian, The HEGRA Collaboration
The Crab Nebula has been observed by the HEGRA (High-Energy Gamma-Ray Astronomy) stereoscopic system of imaging air Cherenkov telescopes (IACTs) for a total of about 200 hrs during…
Correlated intense X-ray and TeV activity of Mrk~501 in 1998 June
Rita M. Sambruna
We present exactly simultaneous X-ray and TeV monitoring with {\it RXTE} and HEGRA of the TeV blazar Mrk 501 during 15 days in 1998 June. After an initial period of very low flux a…
The time averaged TeV energy spectrum of Mkn 501 of the extraordinary 1997 outburst as measured with the stereoscopic Cherenkov telescope system of HEGRA
F. Aharonian
During the several months of the outburst of Mkn 501 in 1997 the source has been monitored in TeV gamma-rays with the HEGRA stereoscopic system of imaging atmospheric Cherenkov tel…
The Cosmic Ray Proton Spectrum determined with the Imaging Atmospheric Cherenkov-Technique
F. Aharonian
The HEGRA system of 4 Imaging Atmospheric Cherenkov Telescopes (IACTs) has been used to determine the flux and the spectrum of cosmic ray protons over a limited energy range around…
Energy Spectrum of TeV Gamma-Rays from Crab Nebula
A. Konopelko
The Crab Nebula has been observed by the HEGRA stereoscopic system of 4 imaging air Cherenkov telescopes (IACTs) for about 100 hours from 1997 September to 1998 March. The recent d…