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4. Limits on the TeV flux of diffuse gamma rays as measured with the HEGRA air shower array

Author

Aharonian, F.A., Akhperjanian, A.G., Barrio, J.A., Bernlöhr, K., Bojahr, H., Bolz, O., Börst, H., Contreras, J.L., Cortina, J., Denninghoff, S., Fonseca, V., Gebauer, H.J., Gonzalez, J.C., Götting, N., Heinzelmann, G., Hermann, G., Heusler, A., Hofmann, W., Horns, D., Ibarra, A., Iserlohe, C., Jung, I., Kankanyan, R., Kestel, M., Kettler, J., Kohnle, A., Konopelko, A., Kornmayer, H., Kranich, D., Krawczynski, H., Lampeitl, H., Lopez, M., Lorenz, E., Lucarelli, F., Magnussen, N., Mang, O., Meyer, H., Mirzoyan, R., Moralejo, A., Oña, E., Padilla, L., Panter, M., Plaga, R., Plyasheshnikov, A., Prahl, J., Pühlhofer, G., Rauterberg, G., Rhode, W., Röhring, A., Rowell, G.P., Sahakian, V., Samorski, M., Schilling, M., Schröder, F., Siems, M., Stamm, W., Tluczykont, M., Völk, H.J., Wiedner, C., and Wittek, W.

Published
2002
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5. TeV γ-ray observations of the Crab and Mkn 501 during moonshine and twilight

Author

Kranich, D., Mirzoyan, R., Petry, D., Raubenheimer, B.C., Aharonian, F., Akhperjanian, A.G., Barrio, J.A., Beck, C., Bernlöhr, K., Bojahr, H., Contreras, J.L., Cortina, J., Daum, A., Deckers, T., Denninghoff, S., Fonseca, V., Gebauer, J., Gonzalez, J.C., Heinzelmann, G., Hemberger, M., Hermann, G., Hess, M., Heusler, A., Hofmann, W., Hohl, H., Horns, D., Ibarra, A., Kankanyan, R., Kestel, M., Kirstein, O., Köhler, C., Konopelko, A., Kornmayer, H., Krawczynski, H., Lampeitl, H., Lindner, A., Lorenz, E., Magnussen, N., Meyer, H., Moralejo, A., Padilla, L., Panter, M., Plaga, R., Plyasheshnikov, A., Prahl, J., Pühlhofer, G., Rauterberg, G., Renault, C., Rhode, W., Roehring, A., Sahakian, V., Samorski, M., Schmele, D., Schröder, F., Stamm, W., Völk, H., Wiebel-Sooth, B., Wiedner, C., Willmer, M., Wirth, H., and Wittek, W.

Published
1999
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7. Variations of the TeV energy spectrum at different flux levels of Mkn 421 observed with the HEGRA system of Cherenkov telescopes

Author

Aharonian, F., Akhperjanian, A., Beilicke, M., Bernlöhr, K., Börst, H., Bojahr, H., Bolz, O., Coarasa, T., Contreras, J., Cortina, J., Costamante, L., Denninghoff, S., Fonseca, V., Girma, M., Götting, N., Heinzelmann, G., Hermann, G., Heusler, A., Hofmann, W., Horns, D., Jung, I., Kankanyan, R., Kestel, M., Kettler, J., Kohnle, A., Konopelko, A., Kornmeyer, H., Kranich, D., Krawczynski, H., Lampeitl, H., Lopez, M., Lorenz, E., Fabrizio Lucarelli, Mang, O., Meyer, H., Mirzoyan, R., Milite, M., Moralejo, A., Ona, E., Panter, M., Plyasheshnikov, A., Pühlhofer, G., Rauterberg, G., Reyes, R., Rhode, W., Ripken, J., Rowell, G., Sahakian, V., Samorski, M., Schilling, M., Siems, M., Sobzynska, D., Stamm, W., Tluczykont, M., Völk, H. J., Wiedner, C. A., Wittek, W., and Remillard, R. A.

Subjects
Physics, Photon, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), Mid infrared, FOS: Physical sciences, HEGRA, Astronomy and Astrophysics, Astrophysics, Power law, Spectral line, Space and Planetary Science, Energy spectrum, Cherenkov radiation, Background radiation
Abstract

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 December 1999 until May 2001. The time averaged energy spectrum is well described by a power law with an exponential cut-off energy at 3.6(+0.4-0.3)_{stat}(+0.9-0.8)_{sys} TeV. The energy spectra derived for different average flux levels ranging from 0.5 to 10 * 10^{-11}ph/cm**2/s follow a clear correlation of photon index and flux level. Generally, the energy spectra are harder for high flux levels. From January to April 2001 Mkn~421 showed rapid variability (doubling time as short as 20 minutes), accompanied with a spectral hardening with increasing flux level within individual nights. For two successive nights (MJD 51989-51991, March 21-23,2001), this correlation of spectral hardness and change in flux has been observed within a few hours. The cut-off energy for the Mkn~421 TeV spectrum remains within the errors constant for the different flux levels and differs by 2.6+/-0.6_stat+/-0.6_sys TeV from the value determined for Mkn~501. This indicates that the observed exponential cut-off in the energy spectrum of Mkn~421 is not solely caused by absorption of multi-TeV photons by pair-production processes with photons of the extragalactic near/mid infrared background radiation., Comment: 12 pages, 9 figures, submitted to Astronomy&Astrophysics

Published
2002
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14. Observations of H1426+428 with HEGRA -- Observations in 2002 and reanalysis of 1999&2000 data

Author

Aharonian, F., Akhperjanian, A., Beilicke, M., Bernlöhr, K., Börst, H. -G, Bojahr, H., Bolz, O., Coarasa, T., Contreras, J. L., Juan Cortina, Costamante, L., Denninghoff, S., Fonseca, M. V., Girma, M., Götting, N., Heinzelmann, G., Hermann, G., Heusler, A., Hofmann, W., Horns, D., Jung, I., Kankanyan, R., Kestel, M., Kohnle, A., Konopelko, A., Kornmeyer, H., Kranich, D., Lampeitl, H., Lopez, M., Lorenz, E., Lucarelli, F., Mang, O., Mazine, D., Meyer, H., Mirzoyan, R., Moralejo, A., Ona-Wilhelmi, E., Panter, M., Plyasheshnikov, A., Prahl, J., Pühlhofer, G., Los Reyes, R., Rhode, W., Ripken, J., Rowell, G., Sahakian, V., Samorski, M., Schilling, M., Siems, M., Sobzynska, D., Stamm, W., Tluczykont, M., Vitale, V., Völk, H. J., Wiedner, C. A., and Wittek, W.

Subjects
Physics, Astrophysics::High Energy Astrophysical Phenomena, Flux, HEGRA, Astronomy and Astrophysics, Astrophysics, Spectral line, Wavelength, Extragalactic background light, Space and Planetary Science, Absorption (electromagnetic radiation), Cherenkov radiation, BL Lac object
Abstract

The HEGRA system of imaging air Cherenkov telescopes has been used to observe the BL Lac object H1426+428 ($z=0.129$) for 217.5 hours in 2002. In this data set alone, the source is detected at a confidence level of $5.3~\sigma$, confirming this object as a TeV source. The overall flux level during the observations in 2002 is found to be a factor of $\approx 2.5$ lower than during the previous observations by HEGRA in 1999&2000. A new spectral analysis has been carried out, improving the signal-to-noise ratio at the expense of a slightly increased systematic uncertainty and reducing the relative energy resolution to $\Delta E/E\le 12 %$ over a wide range of energies. The new method has also been applied to the previously published data set taken in 1999 and 2000, confirming the earlier claim of a flattening of the energy spectrum between 1 and 5 TeV. The data set taken in 2002 shows again a signal at energies above 1 TeV. We combine the energy spectra as determined by the CAT and VERITAS groups with our reanalyzed result of the 1999&2000 data set and apply a correction to account for effects of absorption of high energy photons on extragalactic background light in the optical to mid infrared band. The shape of the inferred source spectrum is mostly sensitive to the characteristics of the extragalactic background light between wavelengths of 1 and 15~$\mu$m, Comment: 12 pages, 4 Figures, submitted to A&A

Published
2003

15. An unidentified TeV source in the vicinity of Cygnus OB2

Author

Aharonian, F., Akhperjanian, A., Beilicke, M., Bernlohr, K., Borst, H., Bojahr, H., Bolz, O., Coarasa, T., Contreras, J., Cortina, J., Denninghoff, S., Fonseca, V., Girma, M., Gotting, N., Heinzelmann, G., Hermann, G., Heusler, A., Hofmann, W., Horns, D., Jung, I., Kankanyan, R., Kestel, M., Kettler, J., Kohnle, A., Konopelko, A., Kornmeyer, H., Kranich, D., Krawczynski, H., Lampeitl, H., Lopez, M., Lorenz, E., Lucarelli, F., Magnussen, N., Mang, O., Meyer, H., Milite, M., Mirzoyan, R., Moralejo, A., Ona, E., Panter, M., Plyasheshnikov, A., Prahl, J., Puhlhofer, G., Rauterberg, G., Reyes, R., Rhode, W., Ripken, J., Rohring, A., Rowell, G. P., Sahakian, V., Samorski, M., Schilling, M., Schroder, F., Siems, M., Sobzynska, D., Stamm, W., Tluczykont, M., Volk, H. J., Wiedner, C. A., Wittek, W. (HEGRA Collaboration), Uchiyama, Yasunobu, and Takahashi, Tadayuki

Subjects
Physics, Astrophysics (astro-ph), Flux, HEGRA, FOS: Physical sciences, Astronomy and Astrophysics, Radius, Astrophysics, Particle acceleration, Stars, Pulsar, Space and Planetary Science, Cygnus OB2, Heliosphere
Abstract

著者人数：62名, Accepted: 2002-08-09, 資料番号: SA1002274000

Published
2002
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21. HESS - The high energy spectroscopic system

Author

Kohnle, A., Aharonian, F., Akhperjanian, A-G., Andronache, M., Auriemma, G., Bulian, N., Chounet, L-M., Degrange, B., Drury, L., Espigat, P., Ferreira, O., Fleury, P., Frenkel, A., Giavannelli, F., Goetting, N., Goret, P., Heinzelmann, G., Heusler, A., Hofmann, W., Horns, D., De Jager, O-C., Jung, I., Kankanyan, R., Kettler, J., Konopelko, A., Krawczynsky, H., Loshe, T., Manigot, P., Mari, S., Martellotti, G., Munz, P., Nayman, P., Panter, M., Penso, G., Pohl, M., Puehlhofer, G., Punch, M., Raubenheimer, B-C., Renault, C., Rivoal, M., Rob, L., Sahakian, C., Sartogo, F., Satriano, C., Schlickeiser, R., Stamm, W., Steenkamp, R., Tavernet, J-P., Toussnel, F., Tuffs, R-J., Vincent, P., Visser, B-V., Voelk, H., Wagner, S., Wiedner, C-A., Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Physique Corpusculaire et Cosmologie - Collège de France (PCC), Collège de France (CdF (institution))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Kieda D. Salamon M. Dingus B., and Lantz, Simone

Subjects
[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], [PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]
Published
1999

22. Astrophysics with HESS

Author

Kohnle, A., Aharonian, F., Akhperjanian, A-G., Andronache, M., Auriemma, G., Bulian, N., Chounet, L-M., Degrange, B., Drury, L., Espigat, P., Ferreira, O., Fleury, P., Frenkel, A., Giavannelli, F., Goetting, N., Goret, P., Heinzelmann, G., Heusler, A., Hofmann, W., Horns, D., De Jager, O-C., Jung, I., Kankanyan, R., Kettler, J., Konopelko, A., Krawczynsky, H., Loshe, T., Manigot, P., Mari, S., Martellotti, G., Munz, P., Nayman, P., Panter, M., Penso, G., Pohl, M., Puehlhofer, G., Punch, M., Raubenheimer, B-C., Renault, C., Rivoal, M., Rob, L., Sahakian, C., Sartogo, F., Satriano, C., Schlickeiser, R., Stamm, W., Steenkamp, R., Tavernet, J-P., Toussnel, F., Tuffs, R-J., Vincent, P., Visser, B-V., Voelk, H., Wagner, S., Wiedner, C-A., Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Physique Corpusculaire et Cosmologie - Collège de France (PCC), Collège de France (CdF (institution))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Kieda D. Salamon M. Dingus B., HESS, and Lantz, Simone

Subjects
[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], [PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]
Published
1999

23. Measurement of the radial distribution of Cherenkov light generated by TeV gamma-ray air showers

Author

Aharonian, F. A., Akhperjanian, A. G., Barrio, J. A., Bernlöhr, K., Bojahr, H., Contreras, J. L., Juan Cortina, Daum, A., Deckers, T., Fonseca, V., Fraß, A., Gonzalez, J. C., Heinzelmann, G., Hemberger, M., Hermann, G., Heß, M., Heusler, A., Hofmann, W., Hohl, H., Holl, I., Horns, D., Ibarra, I., Kankanyan, R., Kestel, M., Kirstein, O., Köhler, C., Konopelko, A., Kornmayer, H., Kranich, D., Krawczynski, H., Lampeitl, H., Lindner, A., Lorenz, E., Magnussen, N., Meyer, H., Mirzoyan, R., Moralejo, A., Padilla, L., Panter, M., Petry, D., Plaga, R., Prahl, J., Prosch, C., Pühlhofer, G., Rauterberg, G., Rhode, W., Röhring, A., Samorski, M., Schmele, D., Schröder, F., Stamm, W., Ulrich, M., Völk, H. J., Wiebel-Sooth, B., Wiedner, C. A., Willmer, M., and Wirth, H.

Subjects
Physics, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), Gamma ray, Astrophysics::Instrumentation and Methods for Astrophysics, HEGRA, FOS: Physical sciences, Astronomy and Astrophysics, IACT, Radial distribution, Astrophysics, Shower, Air shower, High Energy Physics::Experiment, Cherenkov radiation, Zenith
Abstract

Using air showers induced by TeV gamma-rays from Mrk 501, the radial distribution of Cherenkov light is investigated. The shower geometry is reconstructed from the stereoscopic shower images obtained with the telescopes of the HEGRA IACT system. We observe a change in the shape of the light pool with shower energy, and with zenith angle. Data are well reproduced by Monte-Carlo air shower simulations., Comment: 15 Pages, 8 figures, Latex

Published
1998
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24. The time structure of Cherenkov images generated by TeV gamma-rays and by cosmic rays

Author

Heß, M., Bernlöhra, K., Daum, A., Hemberger, M., Hermann, G., Hofmann, W., Lampeitl, H., Aharonian, F. A., Akhperjanian, A. G., Barrio, J. A., Beteta, J. J. G., Contreras, J. L., Juan Cortina, Deckers, T., Fernandez, J., Fonseca, V., Gonzalez, J. C., Heinzelmann, G., Heusler, A., Hohl, H., Holl, I., Horns, D., Kankanyan, R., Kestel, M., Kirstein, O., Köhler, C., Konopelko, A., Kornmayer, H., Kranich, D., Krawczynski, H., Lindner, A., Lorenz, E., Magnussen, N., Meyer, H., Mirzoyan, R., Moralejo, A., Padilla, L., Panter, M., Petry, D., Plaga, R., Prahl, J., Prosch, C., Pühlhofer, G., Rauterberg, G., Rhode, W., Röhring, A., Samorski, M., Sanchez, J. A., Schmele, D., Schröder, F., Stamm, W., Völk, H. J., Wiebel-Sooth, B., Wiedner, C. A., and Willmer, M.

Subjects
Physics, Photon, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), Gamma ray, Astrophysics::Instrumentation and Methods for Astrophysics, HEGRA, FOS: Physical sciences, Astronomy and Astrophysics, Cosmic ray, Astrophysics, law.invention, Core (optical fiber), Telescope, Shower, law, Cherenkov radiation
Abstract

The time profiles of Cherenkov images of cosmic-ray showers and of gamma-ray showers are investigated, using data gathered with the HEGRA system of imaging atmospheric Cherenkov telescopes during the 1997 outbursts of Mrk 501. Photon arrival times are shown to vary across the shower images. The dominant feature is a time gradient along the major axis of the images. The gradient varies with the distance between the telescope and the shower core, and is maximal for large distances. The time profiles of cosmic-ray showers and of gamma-ray showers differ in a characteristic fashion. The main features of the time profiles can be understood in terms of simple geometrical models. Use of the timing information towards improved shower reconstruction and cosmic-ray suppression is discussed., Comment: 25 Pages, 16 figures, Latex

Published
1998
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29. Environmental factors on Microcystin levels in waterbodies

Author

Chorus, I., Lindenschmidt, K.E., Niesel, V., Fastner, J., Wiedner, C., Nixdorf, B., Chorus, I., Lindenschmidt, K.E., Niesel, V., Fastner, J., Wiedner, C., and Nixdorf, B.

Abstract

As discussed in the introduction to Chapter 3, understanding how environmental factors influence cyanotoxin concentrations in waterbodies requires differentiation between two potential mechanisms: a direct impact on cellular toxin content, and/or an impact on competition between genotypes which would lead to dominance of strains or species with or without microcystin. The field results reported in Chapter 2 reinforce published observations that some taxa produce microcystins, others contain certain neurotoxins, and some may contain both or neither. However, further differentiation is possible: Chapter 4.1 shows that Microcystis spp., Planktothrix agardhii and Planktothrix rubescens each typically contain specific microcystin variants, though relative shares of variants as well as total microcystin content of the field populations may vary. Section 4.2 also addresses the level below that of species — i.e. the level of strains or genotypes — by investigating microcystin content in different strains of Microcystis aeruginosa isolated from two lakes. This results demonstrate a substantial variability of of microcystin content between different strains of M. aeruginosa. In conjunction with culture study results reoported in Chapter 3 (which showed little impact of environmental factors on cellular toxin content), this result suggests competition between strain of a species to be a decisive determinant of microcystin concentration in natural populations.

Published
2001

30. Observations of 14 young open star clusters with the HEGRA system of Cherenkov telescopes

Author

Aharonian, F., primary, Akhperjanian, A., additional, Beilicke, M., additional, Bernlöhr, K., additional, Börst, H.-G., additional, Bojahr, H., additional, Bolz, O., additional, Coarasa, T., additional, Contreras, J. L., additional, Cortina, J., additional, Denninghoff, S., additional, Fonseca, M. V., additional, Girma, M., additional, Götting, N., additional, Heinzelmann, G., additional, Hermann, G., additional, Heusler, A., additional, Hofmann, W., additional, Horns, D., additional, Jung, I., additional, Kankanyan, R., additional, Kestel, M., additional, Konopelko, A., additional, Kornmeyer, H., additional, Kranich, D., additional, Lampeitl, H., additional, Lopez, M., additional, Lorenz, E., additional, Lucarelli, F., additional, Mang, O., additional, Meyer, H., additional, Mirzoyan, R., additional, Moralejo, A., additional, Ona-Wilhelmi, E., additional, Panter, M., additional, Plyasheshnikov, A., additional, Pühlhofer, G., additional, de los Reyes, R., additional, Rhode, W., additional, Ripken, J., additional, Rowell, G., additional, Sahakian, V., additional, Samorski, M., additional, Schilling, M., additional, Siems, M., additional, Sobzynska, D., additional, Stamm, W., additional, Tluczykont, M., additional, Vitale, V., additional, Völk, H. J., additional, Wiedner, C. A., additional, and Wittek, W., additional

Published
2006
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32. The Crab Nebula and Pulsar between 500 GeV and 80 TeV: Observations with the HEGRA Stereoscopic Air Cerenkov Telescopes

Author

Aharonian, F., primary, Akhperjanian, A., additional, Beilicke, M., additional, Bernlohr, K., additional, Borst, H.‐G., additional, Bojahr, H., additional, Bolz, O., additional, Coarasa, T., additional, Contreras, J. L., additional, Cortina, J., additional, Denninghoff, S., additional, Fonseca, M. V., additional, Girma, M., additional, Gotting, N., additional, Heinzelmann, G., additional, Hermann, G., additional, Heusler, A., additional, Hofmann, W., additional, Horns, D., additional, Jung, I., additional, Kankanyan, R., additional, Kestel, M., additional, Kohnle, A., additional, Konopelko, A., additional, Kranich, D., additional, Lampeitl, H., additional, Lopez, M., additional, Lorenz, E., additional, Lucarelli, F., additional, Mang, O., additional, Mazin, D., additional, Meyer, H., additional, Mirzoyan, R., additional, Moralejo, A., additional, Ona‐Wilhelmi, E., additional, Panter, M., additional, Plyasheshnikov, A., additional, Puhlhofer, G., additional, de los Reyes, R., additional, Rhode, W., additional, Ripken, J., additional, Rowell, G., additional, Sahakian, V., additional, Samorski, M., additional, Schilling, M., additional, Siems, M., additional, Sobzynska, D., additional, Stamm, W., additional, Tluczykont, M., additional, Vitale, V., additional, Volk, H. J., additional, Wiedner, C. A., additional, and Wittek, W., additional

Published
2004
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33. Search for TeV gamma ray emission from the Andromeda galaxy

Author

Aharonian, F. A., primary, Akhperjanian, A. G., additional, Beilicke, M., additional, Bernlöhr, K., additional, Bojahr, H., additional, Bolz, O., additional, Börst, H., additional, Coarasa, T., additional, Contreras, J. L., additional, Cortina, J., additional, Denninghoff, S., additional, Fonseca, V., additional, Girma, M., additional, Götting, N., additional, Heinzelmann, G., additional, Hermann, G., additional, Heusler, A., additional, Hofmann, W., additional, Horns, D., additional, Jung, I., additional, Kankanyan, R., additional, Kestel, M., additional, Kettler, J., additional, Kohnle, A., additional, Konopelko, A., additional, Kornmeyer, H., additional, Kranich, D., additional, Krawczynski, H., additional, Lampeitl, H., additional, Lopez, M., additional, Lorenz, E., additional, Lucarelli, F., additional, Mang, O., additional, Meyer, H., additional, Mirzoyan, R., additional, Moralejo, A., additional, Ona, E., additional, Panter, M., additional, Plyasheshnikov, A., additional, Pühlhofer, G., additional, Rauterberg, G., additional, Reyes, R., additional, Rhode, W., additional, Ripken, J., additional, Röhring, A., additional, Rowell, G. P., additional, Sahakian, V., additional, Samorski, M., additional, Schilling, M., additional, Siems, M., additional, Sobzynska, D., additional, Stamm, W., additional, Tluczykont, M., additional, Völk, H. J., additional, Wiedner, C. A., additional, and Wittek, W., additional

Published
2003
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36. A search for TeV gamma-ray emission from SNRs, pulsars and unidentified GeV sources in the Galactic plane in the longitude range between $-2^\circ$ and $85^\circ$

Author

Aharonian, F. A., primary, Akhperjanian, A. G., additional, Beilicke, M., additional, Bernlöhr, K., additional, Bojahr, H., additional, Bolz, O., additional, Börst, H., additional, Coarasa, T., additional, Contreras, J. L., additional, Cortina, J., additional, Denninghoff, S., additional, Fonseca, V., additional, Girma, M., additional, Götting, N., additional, Heinzelmann, G., additional, Hermann, G., additional, Heusler, A., additional, Hofmann, W., additional, Horns, D., additional, Jung, I., additional, Kankanyan, R., additional, Kestel, M., additional, Kettler, J., additional, Kohnle, A., additional, Konopelko, A., additional, Kornmeyer, H., additional, Kranich, D., additional, Krawczynski, H., additional, Lampeitl, H., additional, Lopez, M., additional, Lorenz, E., additional, Lucarelli, F., additional, Mang, O., additional, Meyer, H., additional, Mirzoyan, R., additional, Moralejo, A., additional, Ona, E., additional, Panter, M., additional, Plyasheshnikov, A., additional, Pühlhofer, G., additional, Rauterberg, G., additional, Reyes, R., additional, Rhode, W., additional, Ripken, J., additional, Röhring, A., additional, Rowell, G. P., additional, Sahakian, V., additional, Samorski, M., additional, Schilling, M., additional, Siems, M., additional, Sobzynska, D., additional, Stamm, W., additional, Tluczykont, M., additional, Völk, H. J., additional, Wiedner, C. A., additional, and Wittek, W., additional

Published
2002
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37. Search for point sources of gamma radiation above 15 TeV with the HEGRA AIROBICC array

Author

Aharonian, F., primary, Akhperjanian, A., additional, Barrio, J. A., additional, Bernlöhr, K., additional, Börst, H., additional, Bojahr, H., additional, Bolz, O., additional, Contreras, J. L., additional, Cortina, J., additional, Denninghoff, S., additional, Fonseca, V., additional, Gebauer, H. J., additional, González, J., additional, Götting, N., additional, Heinzelmann, G., additional, Hermann, G., additional, Heusler, A., additional, Hofmann, W., additional, Horns, D., additional, Jung, I., additional, Kankanyan, R., additional, Kestel, M., additional, Kettler, J., additional, Kohnle, A., additional, Konopelko, A., additional, Kornmayer, H., additional, Kranich, D., additional, Krawczynski, H., additional, Lampeitl, H., additional, López, M., additional, Lorenz, E., additional, Lucarelli, F., additional, Magnussen, N., additional, Mang, O., additional, Meyer, H., additional, Mirzoyan, R., additional, Moralejo, A., additional, Oña, E., additional, Padilla, L., additional, Panter, M., additional, Plaga, R., additional, Plyasheshnikov, A., additional, Prahl, J., additional, Pühlhofer, G., additional, Rauterberg, G., additional, Röhring, A., additional, Rhode, W., additional, Rowell, G., additional, Sahakian, V., additional, Samorski, M., additional, Schilling, M., additional, Schmele, D., additional, Schröder, F., additional, Sevilla, I., additional, Siems, M., additional, Stamm, W., additional, Tluczykont, M., additional, Völk, H. J., additional, Wiedner, C. A., additional, and Wittek, W., additional

Published
2002
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38. TeV gamma rays from the blazar H 1426+428 and the diffuse extragalactic background radiation

Author

Aharonian, F., primary, Akhperjanian, A., additional, Barrio, J., additional, Beilicke, M., additional, Bernlöhr, K., additional, Börst, H., additional, Bojahr, H., additional, Bolz, O., additional, Contreras, J., additional, Cornils, R., additional, Cortina, J., additional, Denninghoff, S., additional, Fonseca, V., additional, Girma, M., additional, Gonzalez, J., additional, Götting, N., additional, Heinzelmann, G., additional, Hermann, G., additional, Heusler, A., additional, Hofmann, W., additional, Horns, D., additional, Jung, I., additional, Kankanyan, R., additional, Kestel, M., additional, Kettler, J., additional, Kohnle, A., additional, Konopelko, A., additional, Kornmeyer, H., additional, Kranich, D., additional, Krawczynski, H., additional, Lampeitl, H., additional, Lopez, M., additional, Lorenz, E., additional, Lucarelli, F., additional, Magnussen, N., additional, Mang, O., additional, Meyer, H., additional, Mirzoyan, R., additional, Moralejo, A., additional, Ona, E., additional, Padilla, L., additional, Panter, M., additional, Plaga, R., additional, Plyasheshnikov, A., additional, Pühlhofer, G., additional, Rauterberg, G., additional, Röhring, A., additional, Rhode, W., additional, Robrade, J., additional, Rowell, G., additional, Sahakian, V., additional, Samorski, M., additional, Schilling, M., additional, Schröder, F., additional, Sevilla, I., additional, Siems, M., additional, Stamm, W., additional, Tluczykont, M., additional, Völk, H. J., additional, Wiedner, C. A., additional, and Wittek, W., additional

Published
2002
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39. TeV gamma-ray observations of SS-433 and a survey of the surrounding field with the HEGRA IACT-System

Author

Aharonian, F., Akhperjanian, A., Beilicke, M., Bernlöhr, K., Börst, H.-G., Bojahr, H., Bolz, O., Coarasa, T., Contreras, J., Cortina, J., Denninghoff, S., Fonseca, V., Girma, M., Götting, N., Heinzelmann, G., Hermann, G., Heusler, A., Hofmann, W., Horns, D., Jung, I., Kankanyan, R., Kestel, M., Kohnle, A., Konopelko, A., Kranich, D., Lampeitl, H., Lopez, M., Lorenz, E., Lucarelli, F., Mang, O., Mazin, D., Meyer, H., Mirzoyan, R., Moralejo, A., Oña-Wilhelmi, E., Panter, M., Plyasheshnikov, A., Pühlhofer, G., Reyes, R. de los, Rhode, W., Ripken, J., Rowell, G. P., Sahakian, V., Samorski, M., Schilling, M., Siems, M., Sobzynska, D., Stamm, W., Tluczykont, M., Vitale, V., Völk, H. J., Wiedner, C. A., Wittek, W., Aharonian, F., Akhperjanian, A., Beilicke, M., Bernlöhr, K., Börst, H.-G., Bojahr, H., Bolz, O., Coarasa, T., Contreras, J., Cortina, J., Denninghoff, S., Fonseca, V., Girma, M., Götting, N., Heinzelmann, G., Hermann, G., Heusler, A., Hofmann, W., Horns, D., Jung, I., Kankanyan, R., Kestel, M., Kohnle, A., Konopelko, A., Kranich, D., Lampeitl, H., Lopez, M., Lorenz, E., Lucarelli, F., Mang, O., Mazin, D., Meyer, H., Mirzoyan, R., Moralejo, A., Oña-Wilhelmi, E., Panter, M., Plyasheshnikov, A., Pühlhofer, G., Reyes, R. de los, Rhode, W., Ripken, J., Rowell, G. P., Sahakian, V., Samorski, M., Schilling, M., Siems, M., Sobzynska, D., Stamm, W., Tluczykont, M., Vitale, V., Völk, H. J., Wiedner, C. A., and Wittek, W.

Abstract

We present results of a search for TeV γ-ray emission from the microquasar SS-433 and the surrounding region covering a ~$8^\circ$$\times$$8^\circ$field of view. Analysis of data taken with the HEGRA stereoscopic system of imaging atmospheric Čerenkov imaging telescopes reveals no evidence of steady or variable emission from any position. Observation times of over 100 h have been achieved in central parts of the field of view. We set 99% confidence level upper limits to a number of a-priori-chosen objects of interest, including SS-443 and its interaction regions, 32 pulsars, 3 supernova remnants and the GeV source GeV J1907+0537. Our upper limit of 3.2% Crab flux (for energies $E>0.8$TeV) for the eastern-lobe region e3of SS-433 permits, after comparison with X-ray fluxes, a lower limit of $B\geq19~\mu$G on the post-shocked magnetic field in this region. An ensemble upper limit at 0.3% Crab flux ($E>0.7$TeV) from a subset (11) of the 32 pulsars implies a maximum of 4.5% of the spin-down pulsar power is available for TeV γ-ray production. For one of the SNR in our FoV, 3C 396, recent Chandra observations suggest that a central pulsar-driven wind nebula may be the source of X-ray emission. Our upper limit implies that a maximum of 0.1% of the spin-down power from the central source of 3C 396 would be available for TeV γ-rays.

Published
2005
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40. Simultaneous X‐Ray and TeV Gamma‐Ray Observation of the TeV Blazar Markarian 421 during 2000 February and May

Author

Krawczynski, H., primary, Sambruna, R., additional, Kohnle, A., additional, Coppi, P. S., additional, Aharonian, F., additional, Akhperjanian, A., additional, Barrio, J., additional, Bernlohr, K., additional, Borst, H., additional, Bojahr, H., additional, Bolz, O., additional, Contreras, J., additional, Cortina, J., additional, Denninghoff, S., additional, Fonseca, V., additional, Gonzalez, J., additional, Gotting, N., additional, Heinzelmann, G., additional, Hermann, G., additional, Heusler, A., additional, Hofmann, W., additional, Horns, D., additional, Ibarra, A., additional, Jung, I., additional, Kankanyan, R., additional, Kestel, M., additional, Kettler, J., additional, Konopelko, A., additional, Kornmeyer, H., additional, Kranich, D., additional, Lampeitl, H., additional, Lorenz, E., additional, Lucarelli, F., additional, Magnussen, N., additional, Mang, O., additional, Meyer, H., additional, Mirzoyan, R., additional, Moralejo, A., additional, Padilla, L., additional, Panter, M., additional, Plaga, R., additional, Plyasheshnikov, A., additional, Puhlhofer, G., additional, Rauterberg, G., additional, Rohring, A., additional, Rhode, W., additional, Rowell, G., additional, Sahakian, V., additional, Samorski, M., additional, Schilling, M., additional, Schroder, F., additional, Siems, M., additional, Stamm, W., additional, Tluczykont, M., additional, Volk, H. J., additional, Wiedner, C. A., additional, and Wittek, W., additional

Published
2001
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41. A search for gamma-ray emission from the Galactic plane in the longitude range between $\mathsf{37}^\circ$ and $\mathsf{43}^\circ$

Author

Aharonian, F. A., primary, Akhperjanian, A. G., additional, Barrio, J. A., additional, Bernlöhr, K., additional, Bolz, O., additional, Börst, H., additional, Bojahr, H., additional, Contreras, J. L., additional, Cortina, J., additional, Denninghoff, S., additional, Fonseca, V., additional, Gonzalez, J. C., additional, Götting, N., additional, Heinzelmann, G., additional, Hermann, G., additional, Heusler, A., additional, Hofmann, W., additional, Horns, D., additional, Ibarra, A., additional, Iserlohe, C., additional, Jung, I., additional, Kankanyan, R., additional, Kestel, M., additional, Kettler, J., additional, Kohnle, A., additional, Konopelko, A., additional, Kornmeyer, H., additional, Kranich, D., additional, Krawczynski, H., additional, Lampeitl, H., additional, Lorenz, E., additional, Lucarelli, F., additional, Magnussen, N., additional, Mang, O., additional, Meyer, H., additional, Mirzoyan, R., additional, Moralejo, A., additional, Padilla, L., additional, Panter, M., additional, Plaga, R., additional, Plyasheshnikov, A., additional, Prahl, J., additional, Pühlhofer, G., additional, Rhode, W., additional, Röhring, A., additional, Rowell, G. P., additional, Sahakian, V., additional, Samorski, M., additional, Schilling, M., additional, Schröder, F., additional, Siems, M., additional, Stamm, W., additional, Tluczykont, M., additional, Völk, H. J., additional, Wiedner, C. A., additional, and Wittek, W., additional

Published
2001
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42. A study of Tycho's SNR at TeV energies with the HEGRA CT-System

Author

Aharonian, F. A., primary, Akhperjanian, A. G., additional, Barrio, J. A., additional, Bernlöhr, K., additional, Börst, H., additional, Bojahr, H., additional, Bolz, O., additional, Contreras, J. L., additional, Cortina, J., additional, Denninghoff, S., additional, Fonseca, V., additional, Gonzalez, J. C., additional, Götting, N., additional, Heinzelmann, G., additional, Hermann, G., additional, Heusler, A., additional, Hofmann, W., additional, Horns, D., additional, Ibarra, A., additional, Jung, I., additional, Kankanyan, R., additional, Kestel, M., additional, Kettler, J., additional, Kohnle, A., additional, Konopelko, A., additional, Kornmeyer, H., additional, Kranich, D., additional, Krawczynski, H., additional, Lampeitl, H., additional, Lorenz, E., additional, Lucarelli, F., additional, Magnussen, N., additional, Mang, O., additional, Meyer, H., additional, Mirzoyan, R., additional, Moralejo, A., additional, Padilla, L., additional, Panter, M., additional, Plaga, R., additional, Plyasheshnikov, A., additional, Prahl, J., additional, Pühlhofer, G., additional, Rauterberg, G., additional, Röhring, A., additional, Rhode, W., additional, Rowell, G. P., additional, Sahakian, V., additional, Samorski, M., additional, Schilling, M., additional, Schröder, F., additional, Stamm, W., additional, Tluczykont, M., additional, Völk, H. J., additional, Wiedner, C., additional, and Wittek, W., additional

Published
2001
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43. Evidence for TeV gamma ray emission from Cassiopeia A

Author

Aharonian, F., primary, Akhperjanian, A., additional, Barrio, J., additional, Bernlöhr, K., additional, Börst, H., additional, Bojahr, H., additional, Bolz, O., additional, Contreras, J., additional, Cortina, J., additional, Denninghoff, S., additional, Fonseca, V., additional, Gonzalez, J., additional, Götting, N., additional, Heinzelmann, G., additional, Hermann, G., additional, Heusler, A., additional, Hofmann, W., additional, Horns, D., additional, Ibarra, A., additional, Iserlohe, C., additional, Jung, I., additional, Kankanyan, R., additional, Kestel, M., additional, Kettler, J., additional, Kohnle, A., additional, Konopelko, A., additional, Kornmeyer, H., additional, Kranich, D., additional, Krawczynski, H., additional, Lampeitl, H., additional, Lopez, M., additional, Lorenz, E., additional, Lucarelli, F., additional, Magnussen, N., additional, Mang, O., additional, Meyer, H., additional, Mirzoyan, R., additional, Moralejo, A., additional, Ona, E., additional, Padilla, L., additional, Panter, M., additional, Plaga, R., additional, Plyasheshnikov, A., additional, Prahl, J., additional, Pühlhofer, G., additional, Rauterberg, G., additional, Röhring, A., additional, Rhode, W., additional, Rowell, G. P., additional, Sahakian, V., additional, Samorski, M., additional, Schilling, M., additional, Schröder, F., additional, Siems, M., additional, Stamm, W., additional, Tluczykont, M., additional, Völk, H. J., additional, Wiedner, C. A., additional, and Wittek, W., additional

Published
2001
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44. Search for a TeV gamma-ray halo of Mkn 501

Author

Aharonian, F. A., primary, Akhperjanian, A. G., additional, Barrio, J. A., additional, Bernlöhr, K., additional, Bolz, O., additional, Börst, H., additional, Bojahr, H., additional, Contreras, J. L., additional, Cortina, J., additional, Denninghoff, S., additional, Fonseca, V., additional, Gonzalez, J. C., additional, Götting, N., additional, Heinzelmann, G., additional, Hermann, G., additional, Heusler, A., additional, Hofmann, W., additional, Horns, D., additional, Ibarra, A., additional, Iserlohe, C., additional, Jung, I., additional, Kankanyan, R., additional, Kestel, M., additional, Kettler, J., additional, Kohnle, A., additional, Konopelko, A., additional, Kornmeyer, H., additional, Kranich, D., additional, Krawczynski, H., additional, Lampeitl, H., additional, Lorenz, E., additional, Lucarelli, F., additional, Magnussen, N., additional, Mang, O., additional, Meyer, H., additional, Mirzoyan, R., additional, Moralejo, A., additional, Padilla, L., additional, Panter, M., additional, Plaga, R., additional, Plyasheshnikov, A., additional, Prahl, J., additional, Pühlhofer, G., additional, Rhode, W., additional, Röhring, A., additional, Rowell, G. P., additional, Sahakian, V., additional, Samorski, M., additional, Schilling, M., additional, Schröder, F., additional, Siems, M., additional, Stamm, W., additional, Tluczykont, M., additional, Völk, H. J., additional, Wiedner, C., additional, and Wittek, W., additional

Published
2001
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45. The TeV Energy Spectrum of Markarian 501 Measured with the Stereoscopic Telescope System of HEGRA during 1998 and 1999

Author

Aharonian, F., primary, Akhperjanian, A., additional, Barrio, J., additional, Bernlohr, K., additional, Borst, H., additional, Bojahr, H., additional, Bolz, O., additional, Contreras, J., additional, Cortina, J., additional, Denninghoff, S., additional, Fonseca, V., additional, Gonzalez, J., additional, Gotting, N., additional, Heinzelmann, G., additional, Hermann, G., additional, Heusler, A., additional, Hofmann, W., additional, Horns, D., additional, Iserlohe, C., additional, Ibarra, A., additional, Jung, I., additional, Kankanyan, R., additional, Kestel, M., additional, Kettler, J., additional, Kohnle, A., additional, Konopelko, A., additional, Kornmeyer, H., additional, Kranich, D., additional, Krawczynski, H., additional, Lampeitl, H., additional, Lorenz, E., additional, Lucarelli, F., additional, Magnussen, N., additional, Mang, O., additional, Meyer, H., additional, Mirzoyan, R., additional, Moralejo, A., additional, Padilla, L., additional, Panter, M., additional, Plaga, R., additional, Plyasheshnikov, A., additional, Prahl, J., additional, Puhlhofer, G., additional, Rohring, A., additional, Rhode, W., additional, Rowell, G. P., additional, Sahakian, V., additional, Samorski, M., additional, Schilling, M., additional, Schroder, F., additional, Siems, M., additional, Stamm, W., additional, Tluczykont, M., additional, Volk, H., additional, Wiedner, C., additional, and Wittek, W., additional

Published
2001
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46. Reanalysis of the high energy cutoff of the 1997 Mkn 501 TeV energy spectrum

Author

Aharonian, F. A., primary, Akhperjanian, A. G., additional, Barrio, J. A., additional, Bernlöhr, K., additional, Bolz, O., additional, Börst, H., additional, Bojahr, H., additional, Contreras, J. L., additional, Cortina, J., additional, Denninghoff, S., additional, Fonseca, V., additional, Gonzalez, J. C., additional, Götting, N., additional, Heinzelmann, G., additional, Hermann, G., additional, Heusler, A., additional, Hofmann, W., additional, Horns, D., additional, Ibarra, A., additional, Iserlohe, C., additional, Jung, I., additional, Kankanyan, R., additional, Kestel, M., additional, Kettler, J., additional, Kohnle, A., additional, Konopelko, A., additional, Kornmeyer, H., additional, Kranich, D., additional, Krawczynski, H., additional, Lampeitl, H., additional, Lorenz, E., additional, Lucarelli, F., additional, Magnussen, N., additional, Mang, O., additional, Meyer, H., additional, Mirzoyan, R., additional, Moralejo, A., additional, Padilla, L., additional, Panter, M., additional, Plaga, R., additional, Plyasheshnikov, A., additional, Prahl, J., additional, Pühlhofer, G., additional, Rhode, W., additional, Röhring, A., additional, Rowell, G. P., additional, Sahakian, V., additional, Samorski, M., additional, Schilling, M., additional, Schröder, F., additional, Siems, M., additional, Stamm, W., additional, Tluczykont, M., additional, Völk, H. J., additional, Wiedner, C., additional, and Wittek, W., additional

Published
2001
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47. Observation of the Monoceros Loop SNRregion with the HEGRA system of IACTs

Author

Aharonian, F. A., Akhperjanian, A. G., Beilicke, M., Bernlöhr, K., Börst, H.-G., Bojahr, H., Bolz, O., Coarasa, T., Contreras, J. L., Cortina, J., Denninghoff, S., Fonseca, M. V., Girma, M., Götting, N., Heinzelmann, G., Hermann, G., Heusler, A., Hofmann, W., Horns, D., Jung, I., Kankanyan, R., Kestel, M., Kohnle, A., Konopelko, A., Kornmeyer, H., Kranich, D., Lampeitl, H., Lopez, M., Lorenz, E., Lucarelli, F., Mang, O., Meyer, H., Mirzoyan, R., Moralejo, A., Ona-Wilhelmi, E., Panter, M., Plyasheshnikov, A., Pühlhofer, G., Reyes, R. de los, Rhode, W., Ripken, J., Rowell, G., Sahakian, V., Samorski, M., Schilling, M., Siems, M., Sobzynska, D., Stamm, W., Tluczykont, M., Vitale, V., Völk, H. J., Wiedner, C. A., Wittek, W., Aharonian, F. A., Akhperjanian, A. G., Beilicke, M., Bernlöhr, K., Börst, H.-G., Bojahr, H., Bolz, O., Coarasa, T., Contreras, J. L., Cortina, J., Denninghoff, S., Fonseca, M. V., Girma, M., Götting, N., Heinzelmann, G., Hermann, G., Heusler, A., Hofmann, W., Horns, D., Jung, I., Kankanyan, R., Kestel, M., Kohnle, A., Konopelko, A., Kornmeyer, H., Kranich, D., Lampeitl, H., Lopez, M., Lorenz, E., Lucarelli, F., Mang, O., Meyer, H., Mirzoyan, R., Moralejo, A., Ona-Wilhelmi, E., Panter, M., Plyasheshnikov, A., Pühlhofer, G., Reyes, R. de los, Rhode, W., Ripken, J., Rowell, G., Sahakian, V., Samorski, M., Schilling, M., Siems, M., Sobzynska, D., Stamm, W., Tluczykont, M., Vitale, V., Völk, H. J., Wiedner, C. A., and Wittek, W.

Abstract

The array of 5 imaging atmospheric Čerenkov telescopes (IACTs) deployed at La Palma (Canary Islands), and operated by the HEGRA (High Energy Gamma Ray Astronomy) collaboration, was used for observations of the Monoceros Loop SNRregion for a total of about 120 hrs and 20 hrs in ON-source and OFF-source mode, respectively. The giant molecular cloud Rosette Nebula appears in the sky region, close to the south-east part of the SNRrim. Using the HEGRA system of IACTs of rather large field of view (4.3 degree in diameter), we have mapped the extended sky region of $3^\circ \times 3^\circ$associated with the Monoceros SNR/Rosette Nebula, which is centered towards the hard spectrum X-ray point source SAX J0635+533. The EGRET unidentified source of diffuse γ-ray emission (3EG J0634+0521) observed in the energy range between 100 MeV–10 GeV, was effectively in the field of view of our present observations. Also, the GeV source GeV J0633+0645 was within the available field of view. The performance of the IACTs array reveals an energy threshold of 500 GeV and an angular resolution of $0.1^\circ$for γ-rays. In what follows, we present the result of the data analysis and its physical interpretation.

Published
2004
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48. TeV γ-ray light curve and energy spectrum of Mkn 421during its 2001 flare as measured with HEGRA CT1*

Author

Aharonian, F., Akhperjanian, A., Beilicke, M., Bernlöhr, K., Börst, H. G., Bojahr, H., Bolz, O., Coarasa, J. A., Contreras, J. L., Cortina, J., Denninghoff, S., Fonseca, V., Girma, M., Goebel, F., Götting, N., Heinzelmann, G., Hermann, G., Heusler, A., Hofmann, W., Horns, D., Jung, I., Kankanyan, R., Kestel, M., Kettler, J., Kohnle, A., Konopelko, A., Kranich, D., Krawczynski, H., Lampeitl, H., López, M., Lorenz, E., Lucarelli, F., Mang, O., Meyer, H., Mirzoyan, R., Moralejo, A., Oña-Wilhelmi, E., Paneque, D., Panter, M., Plyasheshnikov, A., Pühlhofer, G., Reyes, R. de los, Rhode, W., Ripken, J., Rowell, G., Sahakian, V., Samorski, M., Schilling, M., Schweizer, T., Sevilla, I., Siems, M., Sobczyńska, D., Stamm, W., Tluczykont, M., Tonello, N., Vitale, V., Völk, H. J., Wagner, R. M., Wiedner, C. A., Wittek, W., Aharonian, F., Akhperjanian, A., Beilicke, M., Bernlöhr, K., Börst, H. G., Bojahr, H., Bolz, O., Coarasa, J. A., Contreras, J. L., Cortina, J., Denninghoff, S., Fonseca, V., Girma, M., Goebel, F., Götting, N., Heinzelmann, G., Hermann, G., Heusler, A., Hofmann, W., Horns, D., Jung, I., Kankanyan, R., Kestel, M., Kettler, J., Kohnle, A., Konopelko, A., Kranich, D., Krawczynski, H., Lampeitl, H., López, M., Lorenz, E., Lucarelli, F., Mang, O., Meyer, H., Mirzoyan, R., Moralejo, A., Oña-Wilhelmi, E., Paneque, D., Panter, M., Plyasheshnikov, A., Pühlhofer, G., Reyes, R. de los, Rhode, W., Ripken, J., Rowell, G., Sahakian, V., Samorski, M., Schilling, M., Schweizer, T., Sevilla, I., Siems, M., Sobczyńska, D., Stamm, W., Tluczykont, M., Tonello, N., Vitale, V., Völk, H. J., Wagner, R. M., Wiedner, C. A., and Wittek, W.

Abstract

In the first months of 2001 the AGN Mkn 421showed highly variable, strong TeV activity at flux levels frequently exceeding 1 Crab. Here we present the light curve and energy spectrum of Mkn 421as measured with the HEGRA stand alone telescope CT1. Around 30% of the data were taken under moonlight conditions. The spectrum shows a significant exponential energy cutoff at around 3.4 TeV. The results from the dark night- and the moon data are in excellent agreement with each other. A significant spectral shape variation depending on the flux level has been found. The TeV light curve is also found to be highly correlated with the X-ray light curve of the RXTE / ASM satellite, showing no significant time lag larger than 0.2 d. The derived correlation coefficient of 0.83 corresponds to a $5.2~\sigma$significance.

Published
2003
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49. Detection of TeV gamma-rays from the BL Lac 1ES 1959+650 in its low states and during a major outburst in 2002 *

Author

Aharonian, F., Akhperjanian, A., Beilicke, M., Bernlöhr, K., Börst, H.-G., Bojahr, H., Bolz, O., Coarasa, T., Contreras, J. L., Cortina, J., Denninghoff, S., Fonseca, M. V., Girma, M., Götting, N., Heinzelmann, G., Hermann, G., Heusler, A., Hofmann, W., Horns, D., Jung, I., Kankanyan, R., Kestel, M., Kohnle, A., Konopelko, A., Kornmeyer, H., Kranich, D., Lampeitl, H., Lopez, M., Lorenz, E., Lucarelli, F., Mang, O., Meyer, H., Mirzoyan, R., Moralejo, A., Ona-Wilhelmi, E., Panter, M., Plyasheshnikov, A., Pühlhofer, G., Reyes, R. de los, Rhode, W., Ripken, J., Robrade, J., Rowell, G., Sahakian, V., Samorski, M., Schilling, M., Siems, M., Sobzynska, D., Stamm, W., Tluczykont, M., Vitale, V., Völk, H. J., Wiedner, C. A., Wittek, W., Aharonian, F., Akhperjanian, A., Beilicke, M., Bernlöhr, K., Börst, H.-G., Bojahr, H., Bolz, O., Coarasa, T., Contreras, J. L., Cortina, J., Denninghoff, S., Fonseca, M. V., Girma, M., Götting, N., Heinzelmann, G., Hermann, G., Heusler, A., Hofmann, W., Horns, D., Jung, I., Kankanyan, R., Kestel, M., Kohnle, A., Konopelko, A., Kornmeyer, H., Kranich, D., Lampeitl, H., Lopez, M., Lorenz, E., Lucarelli, F., Mang, O., Meyer, H., Mirzoyan, R., Moralejo, A., Ona-Wilhelmi, E., Panter, M., Plyasheshnikov, A., Pühlhofer, G., Reyes, R. de los, Rhode, W., Ripken, J., Robrade, J., Rowell, G., Sahakian, V., Samorski, M., Schilling, M., Siems, M., Sobzynska, D., Stamm, W., Tluczykont, M., Vitale, V., Völk, H. J., Wiedner, C. A., and Wittek, W.

Abstract

TeV γ-rays from the BL Lac object 1ES 1959+650  have been measured during the years 2000 and 2001 with a significance of 5.2 σat a value of 5.3% of the Crab flux and in May 2002 during strong outbursts with >$23\,\sigma$at a flux level of up to 2.2 Crab, making 1ES 1959+650  the TeV Blazar with the third best event statistics. The deep observation of 197.4 h has been performed with the HEGRA stereoscopic system of 5 imaging atmospheric Cherenkov telescopes (IACT system). 1ES 1959+650  is located at a redshift of $z = 0.047$, providing an intermediate distance between the nearby Blazars Mkn 421 and Mkn 501, and the much more distant object H1426+428. This makes 1ES 1959+650  an important member of the class of TeV Blazars in view of the absorption of TeV photons by the diffuse extragalactic background radiation (DEBRA). The differential energy spectrum of 1ES 1959+650  during the flares can be fitted by a power law with a spectral index of $2.83 \pm 0.14_{\mbox{\tiny stat}} \pm 0.08_{\mbox{\tiny sys}}$or by a power law with an exponential cut-off at $(4.2^{+0.8}_{-0.6~{\mbox{\tiny stat}}} \pm 0.9_{\mbox{\tiny sys}})$TeV and a spectral index of $1.83 \pm 0.15_{\mbox{\tiny stat}} \pm 0.08_{\mbox{\tiny sys}}$. The low state differential energy spectrum obtained with lower statistics can be described by a pure power law with a spectral index of $3.18 \pm 0.17_{\mbox{\tiny stat}} \pm 0.08_{\mbox{\tiny sys}}$.

Published
2003
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50. A search for TeV gamma-ray emission from SNRs, pulsars and unidentified GeV sources in the Galactic plane in the longitude range between $-2^\circ$and $85^\circ$

Author

Aharonian, F. A., Akhperjanian, A. G., Beilicke, M., Bernlöhr, K., Bojahr, H., Bolz, O., Börst, H., Coarasa, T., Contreras, J. L., Cortina, J., Denninghoff, S., Fonseca, V., Girma, M., Götting, N., Heinzelmann, G., Hermann, G., Heusler, A., Hofmann, W., Horns, D., Jung, I., Kankanyan, R., Kestel, M., Kettler, J., Kohnle, A., Konopelko, A., Kornmeyer, H., Kranich, D., Krawczynski, H., Lampeitl, H., Lopez, M., Lorenz, E., Lucarelli, F., Mang, O., Meyer, H., Mirzoyan, R., Moralejo, A., Ona, E., Panter, M., Plyasheshnikov, A., Pühlhofer, G., Rauterberg, G., Reyes, R., Rhode, W., Ripken, J., Röhring, A., Rowell, G. P., Sahakian, V., Samorski, M., Schilling, M., Siems, M., Sobzynska, D., Stamm, W., Tluczykont, M., Völk, H. J., Wiedner, C. A., Wittek, W., Aharonian, F. A., Akhperjanian, A. G., Beilicke, M., Bernlöhr, K., Bojahr, H., Bolz, O., Börst, H., Coarasa, T., Contreras, J. L., Cortina, J., Denninghoff, S., Fonseca, V., Girma, M., Götting, N., Heinzelmann, G., Hermann, G., Heusler, A., Hofmann, W., Horns, D., Jung, I., Kankanyan, R., Kestel, M., Kettler, J., Kohnle, A., Konopelko, A., Kornmeyer, H., Kranich, D., Krawczynski, H., Lampeitl, H., Lopez, M., Lorenz, E., Lucarelli, F., Mang, O., Meyer, H., Mirzoyan, R., Moralejo, A., Ona, E., Panter, M., Plyasheshnikov, A., Pühlhofer, G., Rauterberg, G., Reyes, R., Rhode, W., Ripken, J., Röhring, A., Rowell, G. P., Sahakian, V., Samorski, M., Schilling, M., Siems, M., Sobzynska, D., Stamm, W., Tluczykont, M., Völk, H. J., Wiedner, C. A., and Wittek, W.

Abstract

Using the HEGRA system of imaging atmospheric Cherenkov telescopes, one quarter of the Galactic plane ($-2^\circ < l < 85^\circ$) was surveyed for TeV gamma-ray emission from point sources and moderately extended sources (Ø$\;\le0.8^\circ$). The region covered includes 86 known pulsars (PSR), 63 known supernova remnants (SNR) and nine GeV sources, representing a significant fraction of the known populations. No evidence for emission of TeV gamma radiation was detected, and upper limits range from 0.15 Crab units up to several Crab units, depending on the observation time and zenith angles covered. The ensemble sums over selected SNR and pulsar subsamples and over the GeV-sources yield no indication of emission from these potential sources. The upper limit for the SNR population is 6.7% of the Crab flux and for the pulsar ensemble is 3.6% of the Crab flux.

Published
2002
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