Skip to main content

Research Repository

Advanced Search

Outputs (106)

Fast variability of tera-electron volt gamma rays from the radio galaxy M87 (2006)
Journal Article
Aharonian, F., Akhperjanian, A., Bazer-Bachi, A., Beilicke, M., Benbow, W., Berge, D., …Ward, M. (2006). Fast variability of tera-electron volt gamma rays from the radio galaxy M87. Science, 314(5804), 1424-1427. https://doi.org/10.1126/science.1134408

The detection of fast variations of the tera–electron volt (TeV) (1012 eV) -ray flux, on time scales of days, from the nearby radio galaxy M87 is reported. These variations are about 10 times as fast as those observed in any other wave band and imply... Read More about Fast variability of tera-electron volt gamma rays from the radio galaxy M87.

Observations of the crab nebula with HESS (2006)
Journal Article
Aharonian, F., Akhperjanian, A., Bazer-Bachi, A., Beilicke, M., Benbow, W., Berge, D., …Ward, M. (2006). Observations of the crab nebula with HESS. Astronomy & Astrophysics, 457(3), 899-915

Discovery of the two “wings” of the Kookaburra complex in VHE γ-rays with HESS (2006)
Journal Article
Aharonian, F., Akhperjanian, A., Bazer-Bachi, A., Beilicke, M., Benbow, W., Berge, D., …Ward, M. (2006). Discovery of the two “wings” of the Kookaburra complex in VHE γ-rays with HESS. Astronomy & Astrophysics, 456(1), 245-251. https://doi.org/10.1051/0004-6361%3A20065511

Aims.Search for Very High Energy $\gamma$-ray emission in the Kookaburra complex through observations with the HESS array. Methods.Stereoscopic imaging of Cherenkov light emission of the $\gamma$-ray showers in the atmosphere is used for the reconstr... Read More about Discovery of the two “wings” of the Kookaburra complex in VHE γ-rays with HESS.

Discovery of very high energy γ-ray emission from the BL Lacertae object H 2356-309 with the HESS Cherenkov telescopes (2006)
Journal Article
Aharonian, F., Akhperjanian, A., Bazer-Bachi, A., Beilicke, M., Benbow, W., Berge, D., …Ward, M. (2006). Discovery of very high energy γ-ray emission from the BL Lacertae object H 2356-309 with the HESS Cherenkov telescopes. Astronomy & Astrophysics, 455(2), 461-466. https://doi.org/10.1051/0004-6361%3A20054732

The extreme synchrotron BL Lac object H 2356-309, located at a redshift of z = 0.165, was observed from June to December 2004 with a total exposure of $\approx$40 h live-time with the HESS (High Energy Stereoscopic System) array of atmospheric-Cheren... Read More about Discovery of very high energy γ-ray emission from the BL Lacertae object H 2356-309 with the HESS Cherenkov telescopes.

A detailed spectral and morphological study of the gamma-ray supernovaremnant RX J1713.7-3946 with HESS (2006)
Journal Article
Aharonian, F., Akhperjanian, A., Bazer-Bachi, A., Beilicke, M., Benbow, W., Berge, D., …Wagner, S. (2006). A detailed spectral and morphological study of the gamma-ray supernovaremnant RX J1713.7-3946 with HESS. Astronomy & Astrophysics, 449(1), 223-242. https://doi.org/10.1051/0004-6361%3A20054279

Aims.We present results from deep observations of the Galactic shell-type supernova remnant (SNR) RX J1713.7-3946 (also known as G347.3-0.5 ) conducted with the complete HESS array in 2004. Methods.Detailed morphological and spatially resolved spectr... Read More about A detailed spectral and morphological study of the gamma-ray supernovaremnant RX J1713.7-3946 with HESS.

A low level of extragalactic background light as revealed by big gamma-rays from blazars (2006)
Journal Article
Aharonian, F., Akhperjanian, A., Bazer-Bachi, A., Beilicke, M., Benbow, W., Berge, D., …Wagner, S. (2006). A low level of extragalactic background light as revealed by big gamma-rays from blazars. Nature, 440(7087), 1018-1021. https://doi.org/10.1038/nature04680

The diffuse extragalactic background light consists of the sum of the starlight emitted by galaxies through the history of the Universe, and it could also have an important contribution from the 'first stars', which may have formed before galaxy form... Read More about A low level of extragalactic background light as revealed by big gamma-rays from blazars.

First detection of a VHE gamma-ray spectral maximum from a cosmicsource: HESS discovery of the Vela X nebula (2006)
Journal Article
Aharonian, F., Akhperjanian, A., Bazer-Bachi, A., Beilicke, M., Benbow, W., Berge, D., …Ward, M. (2006). First detection of a VHE gamma-ray spectral maximum from a cosmicsource: HESS discovery of the Vela X nebula. Astronomy & Astrophysics, 448(2), L43-L47. https://doi.org/10.1051/0004-6361%3A200600014

The Vela supernova remnant (SNR) is a complex region containing a number of sources of non-thermal radiation. The inner section of this SNR, within 2 degrees of the pulsar PSR B0833-45 , has been observed by the HESS $\gamma$-ray atmospheric Cherenko... Read More about First detection of a VHE gamma-ray spectral maximum from a cosmicsource: HESS discovery of the Vela X nebula.

A possible association of the new VHE γ-ray source HESS J1825–137 with the pulsar wind nebula G 18.0–0.7. (2005)
Journal Article
Aharonian, F., Akhperjanian, A., Bazer-Bachi, A., Beilicke, M., Benbow, W., Berge, D., …Wagner, S. (2005). A possible association of the new VHE γ-ray source HESS J1825–137 with the pulsar wind nebula G 18.0–0.7. Astronomy & Astrophysics, 442(3), L25-L29. https://doi.org/10.1051/0004-6361%3A200500180

We report on a possible association of the recently discovered very high-energy γ-ray source HESS J1825–137 with the pulsar wind nebula (commonly referred to as G 18.0–0.7) of the 2.1 × 104 year old Vela-like pulsar PSR B1823–13. HESS J1825–137 was d... Read More about A possible association of the new VHE γ-ray source HESS J1825–137 with the pulsar wind nebula G 18.0–0.7..

Multi-wavelength observations of PKS 2155-304 with HESS (2005)
Journal Article
Aharonian, F., Akhperjanian, A., Bazer-Bachi, A., Beilicke, M., Benbow, W., Berge, D., …Wagner, S. (2005). Multi-wavelength observations of PKS 2155-304 with HESS. Astronomy & Astrophysics, 442(3), 895-907. https://doi.org/10.1051/0004-6361%3A20053353

The High Energy Stereoscopic System (HESS) has observed the high-frequency peaked BL Lac object PKS 2155- 304 in 2003 between October 19 and November 26 in Very High Energy (VHE) gamma-rays (E >= 160 GeV for these observations). Observations were car... Read More about Multi-wavelength observations of PKS 2155-304 with HESS.

Observations of selected AGN with HESS (2005)
Journal Article
Aharonian, F., Akhperjanian, A., Bazer-Bachi, A., Beilicke, M., Benbow, W., Berge, D., …Wagner, S. (2005). Observations of selected AGN with HESS. Astronomy & Astrophysics, 441(2), 465-472

A search for very high energy gamma-ray emission from the starburstgalaxy NGC253 with HESS (2005)
Journal Article
Aharonian, F., Akhperjanian, A., Bazer-Bachi, A., Beilicke, M., Benbow, W., Berge, D., …Wagner, S. (2005). A search for very high energy gamma-ray emission from the starburstgalaxy NGC253 with HESS. Astronomy & Astrophysics, 442(1), 177-183. https://doi.org/10.1051/0004-6361%3A20053521

We present the result of 28 h of observations of the nearby starburst galaxy NGC 253 with the HESS$\,$detector in 2003. We find no evidence for very high energy $\gamma$-ray emission from this object. Gamma-ray emission above 400 GeV from NGC 253 had... Read More about A search for very high energy gamma-ray emission from the starburstgalaxy NGC253 with HESS.

Discovery of the binary pulsar PSR B1259-63 in very-high-energy gamma rays around periastron with HESS. (2005)
Journal Article
Aharonian, F., Akhperjanian, A., Aye, K., Bazer-Bachi, A., Beilicke, M., Benbow, W., …Wagner, S. (2005). Discovery of the binary pulsar PSR B1259-63 in very-high-energy gamma rays around periastron with HESS. Astronomy & Astrophysics, 442(1), 1-10. https://doi.org/10.1051/0004-6361%3A20052983

We report the discovery of very-high-energy (VHE) $\gamma$-ray emission of the binary system PSR B1259-63 / SS 2883 of a radio pulsar orbiting a massive, luminous Be star in a highly eccentric orbit. The observations around the 2004 periastron passag... Read More about Discovery of the binary pulsar PSR B1259-63 in very-high-energy gamma rays around periastron with HESS..

Discovery of very high energy gamma rays associated with an x-ray binary (2005)
Journal Article
Aharonian, F., Akhperjanian, A., Aye, K., Bazer-Bachi, A., Beilicke, M., Benbow, W., …Wagner, S. (2005). Discovery of very high energy gamma rays associated with an x-ray binary. Science, 309(5735), 746-749. https://doi.org/10.1126/science.1113764

X-ray binaries are composed of a normal star in orbit around a neutron star or stellar-mass black hole. Radio and x-ray observations have led to the presumption that some x-ray binaries called microquasars behave as scaled-down active galactic nuclei... Read More about Discovery of very high energy gamma rays associated with an x-ray binary.

Detection of TeV γ-ray emission from the shell-type supernova remnant RX J0852.0-4622 with HESS (2005)
Journal Article
Aharonian, F., Akhperjanian, A., Bazer-Bachi, A., Beilicke, M., Benbow, W., Berge, D., …Wagner, S. (2005). Detection of TeV γ-ray emission from the shell-type supernova remnant RX J0852.0-4622 with HESS. Astronomy & Astrophysics, 437(1), L7-L10. https://doi.org/10.1051/0004-6361%3A200500130

We report the detection of TeV $\gamma$-rays from the shell-type supernova remnant RX J0852.0-4622 with data of 3.2 h of live time recorded with HESS in February 2004. An excess of ( $700 \pm 60$) events from the whole remnant with a significance of... Read More about Detection of TeV γ-ray emission from the shell-type supernova remnant RX J0852.0-4622 with HESS.

Discovery of extended VHE gamma-ray emission from the asymmetric pulsar wind nebula in MSH 15-52 with HESS (2005)
Journal Article
Aharonian, F., Akhperjanian, A., Aye, K., Bazer-Bachi, A., Beilicke, M., Benbow, W., …Wagner, S. (2005). Discovery of extended VHE gamma-ray emission from the asymmetric pulsar wind nebula in MSH 15-52 with HESS. Astronomy & Astrophysics, 435(1), L17-L20. https://doi.org/10.1051/0004-6361%3A200500105

The Supernova Remnant MSH 15-52 has been observed in very high energy (VHE) γ-rays using the HESS 4-telescope array located in Namibia. A γ-ray signal is detected at the 25 sigma level during an exposure of 22.1 h live time. The image reveals an elli... Read More about Discovery of extended VHE gamma-ray emission from the asymmetric pulsar wind nebula in MSH 15-52 with HESS.

A new population of very high energy gamma-ray sources in the Milky Way (2005)
Journal Article
Aharonian, F., Akhperjanian, A., Aye, K., Bazer-Bachi, A., Beilicke, M., Benbow, W., …Wagner, S. (2005). A new population of very high energy gamma-ray sources in the Milky Way. Science, 307(5717), 1938-1942. https://doi.org/10.1126/science.1108643

Very high energy {gamma}-rays probe the long-standing mystery of the origin of cosmic rays. Produced in the interactions of accelerated particles in astrophysical objects, they can be used to image cosmic particle accelerators. A first sensitive surv... Read More about A new population of very high energy gamma-ray sources in the Milky Way.

Search for TeV emission from the region around PSR B1706-44 with the HESS experiment (2005)
Journal Article
Aharonian, F., Akhperjanian, A., Aye, K., Bazer-Bachi, A., Beilicke, M., Benbow, W., …Wagner, S. (2005). Search for TeV emission from the region around PSR B1706-44 with the HESS experiment. Astronomy & Astrophysics, 432(1), L9-L12. https://doi.org/10.1051/0004-6361%3A200500008

The region around PSR B1706–44 has been observed with the HESS imaging atmospheric Cherenkov telescopes in 2003. No evidence for γ-ray emission in the TeV range was found at the pulsar position or at the radio arc which corresponds to the supernova r... Read More about Search for TeV emission from the region around PSR B1706-44 with the HESS experiment.

Atmospheric sensing for the H.E.S.S. array (2005)
Conference Proceeding
Aye, K., Brown, A., Chadwick, P., Hadjichristidis, C., Latham, I., Le Gallou, R., …Collaboration, H. (2005). Atmospheric sensing for the H.E.S.S. array. In F. A. Aharonian, H. Völk, & D. Horns (Eds.), High energy gamma-ray astronomy: 2nd International Symposium on High Energy Gamma-Ray Astronomy, Heidelberg, Germany, 26-30 July 2004 (724-729). https://doi.org/10.1063/1.1878491

Several atmospheric monitoring instruments have been installed at the H.E.S.S. gamma‐ray observatory in Namibia. Firstly, Heitronics KT19 infrared radiometers, aligned paraxially with the H.E.S.S. telescopes, measure the infrared radiation of the wat... Read More about Atmospheric sensing for the H.E.S.S. array.

H.E.S.S. observations of PKS 2155-304 (2005)
Journal Article
Aharonian, F., Akhperjanian, A., Aye, K., Bazer-Bachi, A., Beilicke, M., Benbow, W., …Wagner, S. (2005). H.E.S.S. observations of PKS 2155-304. Astronomy & Astrophysics, 430(3), 865-875. https://doi.org/10.1051/0004-6361%3A20041853

The high-frequency peaked BL Lac PKS 2155-304 at redshift z=0.117 has been detected with high significance (~45sigma) at energies greater than 160 GeV, using the H.E.S.S. stereoscopic array of imaging air-Cherenkov telescopes in Namibia. A strong sig... Read More about H.E.S.S. observations of PKS 2155-304.

High-energy particle acceleration in the shell of a supernova remnant (2004)
Journal Article
Aharonian, F., Akhperjanian, A., Aye, K., Bazer-Bachi, A., Beilicke, M., Benbow, W., …Wagner, S. (2004). High-energy particle acceleration in the shell of a supernova remnant. Nature, 432(7013), 75-77. https://doi.org/10.1038/nature02960

A significant fraction of the energy density of the interstellar medium is in the form of high-energy charged particles (cosmic rays)1. The origin of these particles remains uncertain. Although it is generally accepted that the only sources capable o... Read More about High-energy particle acceleration in the shell of a supernova remnant.

Calibration of cameras of the H.E.S.S. detector (2004)
Journal Article
Aharonian, F., Akhperjanian, A., Aye, K., Bazer-Bachi, A., Beilicke, M., Benbow, W., …Wagner, S. (2004). Calibration of cameras of the H.E.S.S. detector. Astroparticle Physics, 22(2), 109-125. https://doi.org/10.1016/j.astropartphys.2004.06.006

H.E.S.S.—the high energy stereoscopic system—is a new system of large atmospheric Cherenkov telescopes for GeV/TeV astronomy. Each of the four telescopes of 107 m2 mirror area is equipped with a 960-pixel photomultiplier-tube camera. This paper descr... Read More about Calibration of cameras of the H.E.S.S. detector.

Very high energy gamma rays from the direction of Sagittarius A<SUP>*</SUP> (2004)
Journal Article
Aharonian, F., Akhperjanian, A., Aye, K., Bazer-Bachi, A., Beilicke, M., Benbow, W., …Wagner, S. (2004). Very high energy gamma rays from the direction of Sagittarius A*. Astronomy & Astrophysics, 425(1), L13-L17. https://doi.org/10.1051/0004-6361%3A200400055

We report the detection of a point-like source of very high energy (VHE) -rays coincident within 1' of Sgr A *, obtained with the HESS array of Cherenkov telescopes. The -rays exhibit a power-law energy spectrum with a spectral index of and a flux ab... Read More about Very high energy gamma rays from the direction of Sagittarius A<SUP>*</SUP>.

Very high energy gamma-rays from Centaurus X-3: indications and implications (2002)
Journal Article
Atoyan, A., Aye, K., Chadwick, P., Daniel, M., Lyons, K., McComb, T., …Rayner, S. (2002). Very high energy gamma-rays from Centaurus X-3: indications and implications. Astronomy & Astrophysics, 383(3), 864-880. https://doi.org/10.1051/0004-6361%3A20011732

We present the results of a detailed timing analysis of observations of Cen X-3 taken by the University of Durham Mark 6 imaging atmospheric Cherenkov telescope in 1997-1999. The presence of a TeV gamma -ray signal at the overall >= 4.5sigma signific... Read More about Very high energy gamma-rays from Centaurus X-3: indications and implications.

Very high energy gamma rays from Cen X-3 (2001)
Journal Article
Chadwick, P., Lyons, K., McComb, T., Orford, K., Osborne, J., Rayner, S., …Turver, K. (2001). Very high energy gamma rays from Cen X-3

VHE gamma rays from binary systems (2001)
Conference Proceeding
Chadwick, P., Chaty, S., Daniel, M., Haswell, C., Kolb, U., McComb, T., …Rayner, S. (2001). VHE gamma rays from binary systems. In F. Aharonian, & H. Volk (Eds.),

VHE gamma ray observations of Centaurus X-3 (2000)
Journal Article
Chadwick, P., Daniel, M., Lyons, K., McComb, T., McKenny, J., Nolan, S., …Turver, K. (2000). VHE gamma ray observations of Centaurus X-3. Astronomy and Astrophysics, 364, 165-169

Geomagnetic effects on atmospheric Cerenkov images (1999)
Journal Article
Chadwick, P., Lyons, K., McComb, T., Orford, K., Osborne, J., Rayner, S., …Turver, K. (1999). Geomagnetic effects on atmospheric Cerenkov images. Journal of Physics G: Nuclear and Particle Physics, 25, 1223-1233

Centaurus X-3: A Source of High-Energy Gamma Rays (1998)
Journal Article
Chadwick, P., Dickinson, M., Dipper, N., Kendall, T., McComb, T., Orford, K., …Turver, K. (1998). Centaurus X-3: A Source of High-Energy Gamma Rays. Astrophysical Journal, 503, 391-

Soft X-rays and cosmic gamma-rays. (1996)
Journal Article
Osborne, J., Wolfendale, A., & Zhang, L. (1996). Soft X-rays and cosmic gamma-rays. Astronomy and astrophysics. Supplement series, 120, 419-

Soft X-rays and cosmic gamma-rays (1995)
Journal Article
Osborne, J., Wolfendale, A., & Zhang, L. (1995). Soft X-rays and cosmic gamma-rays. Monthly Notices of the Royal Astronomical Society, 276, 409-416

A supernova remnant associated with the young gamma-ray pulsar PSR1706-44 (1993)
Journal Article
McAdam, W., Osborne, J., & Parkinson, M. (1993). A supernova remnant associated with the young gamma-ray pulsar PSR1706-44. Nature, 361(6412), 516-518. https://doi.org/10.1038/361516a0

THE Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory satellite recently detected1 pulsed -radiation from the radio pulsar PSR1706–44; this is only the fourth radio pulsar to be identified as a -ray source. The oth... Read More about A supernova remnant associated with the young gamma-ray pulsar PSR1706-44.

A technique for separating the galactic thermal radio emission from the non-thermal component by means of the associated infrared emission (1989)
Journal Article
Broadbent, A., Osborne, J., & Haslam, C. (1989). A technique for separating the galactic thermal radio emission from the non-thermal component by means of the associated infrared emission. Monthly Notices of the Royal Astronomical Society, 237, 381-410

The correlation between the IRAS 60-micron band emission from the galactic disk and radio continuum emissions measured at 11 and 6 cm is discussed. The contribution of the radio continuum at these frequencies from H II is determined. The 60-micron ba... Read More about A technique for separating the galactic thermal radio emission from the non-thermal component by means of the associated infrared emission.

A Procedure for Distinguishing Thermal and Synchrotron Components of the Radio Continuum Emission of the Galactic Disc (1988)
Book Chapter
Broadbent, A., Osborne, J., & Haslam, C. (1988). A Procedure for Distinguishing Thermal and Synchrotron Components of the Radio Continuum Emission of the Galactic Disc. In A. Lawrence (Ed.), Comets to Cosmology: Proceedings of the Third IRAS Conference Held at Queen Mary College, University of London July 6–10, 1987 (109-). Springer Verlag. https://doi.org/10.1007/bfb0118795

Zenith-Angle Dependence of Cosmic-Ray Muons (1971)
Journal Article
Bergeson, H., Bolingbroke, G., Carlson, G., Groom, D., Keuffel, J., Morrison, J., & Osborne, J. (1971). Zenith-Angle Dependence of Cosmic-Ray Muons. Physical Review Letters, 27, 160-163

Range fluctuations for muons of energy up to 106 GeV. (1968)
Journal Article
Osborne, J., Wolfendale, A., & Young, E. (1968). Range fluctuations for muons of energy up to 106 GeV. Journal of Physics A: Mathematical and General, 1(1), 55-60. https://doi.org/10.1088/0305-4470/1/1/308

Recent measurements on cosmic rays deep underground have led to the necessity of studying the effect of fluctuations in range for muons of energy to some 106 GeV and ranges down to 15 000 m.w.e. The results of such calculations are given here; in the... Read More about Range fluctuations for muons of energy up to 106 GeV..

The energy spectra of atmospheric and neutrino-induced muons. (1968)
Journal Article
Craig, R., Osborne, J., Wolfendale, A., & Young, E. (1968). The energy spectra of atmospheric and neutrino-induced muons. Canadian Journal of Physics, 46(10), S352-S357. https://doi.org/10.1139/p68-245

The interrelation of the primary energy spectrum and the energy spectra of muons and neutrinos is examined. The energy spectra of "atmospheric" muons at ground level and underground are calculated for various assumptions about the form of the depth–i... Read More about The energy spectra of atmospheric and neutrino-induced muons..

The Kolar Gold Fields neutrino project. (1968)
Journal Article
Menon, M., Naranan, E., Narasimham, V., Hinotani, K., Ito, N., Miyake, S., …Wolfendale, A. (1968). The Kolar Gold Fields neutrino project. Canadian Journal of Physics, 46(10), S344-S349. https://doi.org/10.1139/p68-243

In the underground laboratory at a depth of 7 600 ft in the Kolar Gold Mines, South India, five telescopes have been in operation for a study of the cosmic radiation which penetrates to such depths. In an exposure of 677 400 m2 sr h (for isotropic ra... Read More about The Kolar Gold Fields neutrino project..

V. Studies of Cosmic Ray Neutrino Interactions in the Kolar Gold Field Experiment (1967)
Journal Article
Menon, M., Naranan, S., Narasimham, V., Hinotani, K., Ito, N., Miyake, S., …Wolfendale, A. (1967). V. Studies of Cosmic Ray Neutrino Interactions in the Kolar Gold Field Experiment. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 301(1465), 137-157. https://doi.org/10.1098/rspa.1967.0197

Results are presented of an experiment to study the penetrating particles in the cosmic radiation deep underground, at a depth of 7500 m.w.e. (standard rock). The events recorded are attributable, in the main, to muons produced either in the atmosphe... Read More about V. Studies of Cosmic Ray Neutrino Interactions in the Kolar Gold Field Experiment.