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1. 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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2. The 2(nd) Berlin BedRest Study: protocol and implementation

Author

Belavy DL 1, Bock O 1, Börst H 1, Armbrecht G 1, Gast U 1, Degner C 1, Beller G 1, Soll H 2, Salanova M 3, Habazettl H. 4, Heer M 5, de Haan A 6, Stegeman DF 6, 7, Cerretelli P 8, Blottner D 3, Rittweger J 9, Gelfi C 10, Kornak U 11, and Felsenberg D 1

Subjects
Countermeasures, Spaceflight, Microgravity, Inactivity, Exercise
Abstract

Long-term bed-rest is used to simulate the effect of spaceflight on the human body and test different kinds of countermeasures. The 2nd Berlin BedRest Study (BBR2-2) tested the efficacy of whole-body vibration in addition to high-load resisitance exercise in preventing bone loss during bed-rest. Here we present the protocol of the study and discuss its implementation. Twenty-four male subjects underwent 60-days of six-degree head down tilt bed-rest and were randomised to an inactive control group (CTR), a high-load resistive exercise group (RE) or a high-load resistive exercise with whole-body vibration group (RVE). Subsequent to events in the course of the study (e.g. subject withdrawal), 9 subjects participated in the CTR-group, 7 in the RVE-group and 8 (7 beyond bed-rest day-30) in the RE-group. Fluid intake, urine output and axiallary temperature increased during bed-rest (p=.17). Body weight changes differed between groups (p

Published
2010

3. 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

4. A search for gamma-ray emission from the Galactic plane in the longitude range between 37° and 43°

Author

Aharonian, F. A., Akhperjanian, A. G., Barrio, J. A., Bernlöhr, K., Bolz, O., Börst, H., Bojahr, H., Contreras, J. L., Juan Cortina, Denninghoff, S., Fonseca, V., 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., Kornmeyer, H., Kranich, D., Krawczynski, H., Lampeitl, H., Lorenz, E., Lucarelli, F., Magnussen, N., Mang, O., Meyer, H., Mirzoyan, R., Moralejo, A., Padilla, L., Panter, M., Plaga, R., Plyasheshnikov, A., Prahl, J., Pühlhofer, 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. A., and Wittek, W.

5. Is the giant radio galaxy M 87 a TeV gamma-ray emitter?

Author

Aharonian, F., Akhperjanian, A., Beilicke, M., Bernlöhr, K., Börst, H. -G, Bojahr, H., Bolz, O., Coarasa, T., Contreras, J. L., Juan Cortina, 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., 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.

6. Search for TeV gamma ray emission from the Andromeda galaxy

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., Gavin Rowell, Sahakian, V., Samorski, M., Schilling, M., Siems, M., Sobzynska, D., Stamm, W., Tluczykont, M., Völk, H. J., Wiedner, C. A., and Wittek, W.

Subjects
Physics, Range (particle radiation), Annihilation, Andromeda Galaxy, Astrophysics::High Energy Astrophysical Phenomena, Dark matter, Astrophysics (astro-ph), Gamma ray, Flux, HEGRA, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Space and Planetary Science, Cherenkov radiation, Astrophysics::Galaxy Astrophysics
Abstract

Using the HEGRA system of imaging atmospheric Cherenkov telescopes, the Andromeda galaxy (M31) was surveyed for TeV gamma ray emission. Given the large field of view of the HEGRA telescopes, three pointings were sufficient to cover all of M31, including also M32 and NGC205. No indications for point sources of TeV gamma rays were found. Upper limits are given at a level of a few percent of the Crab flux. A specific search for monoenergetic gamma-ray lines from annihilation of supersymmetric dark matter particles accumulating near the center of M31 resulted in flux limits in the 10^-13/cm^2s range, well above the predicted MSSM flux levels except for models with pronounced dark-matter spikes or strongly enhanced annihilation rates., Comment: Latex, 7 pages, 4 Figures, submitted to A&A

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

Author

Aharonian, F., Akhperjanian, A., Barrio, J. A., Bernlöhr, K., Börst, H., Bojahr, H., Bolz, O., Contreras, J. L., Cortina, J., Denninghoff, S., Fonseca, V., Gebauer, H. J., González, J., Götting, N., Heinzelmann, G., Hermann, G., Heusler, A., Hofmann, W., Horns, D., Jung, I., Kankanyan, R., Kestel, M., Kettler, J., Kohnle, A., Konopelko, A., Kornmayer, H., Kranich, D., Krawczynski, H., Lampeitl, H., López, 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., Röhring, A., Rhode, W., Gavin Rowell, Sahakian, V., Samorski, M., Schilling, M., Schmele, D., Schröder, F., Sevilla, I., Siems, M., Stamm, W., Tluczykont, M., Völk, H. J., Wiedner, C. A., and Wittek, W.

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

Author

Aharonian, F., Akhperjanian, A., Barrio, J., Beilicke, M., Bernlöhr, K., Börst, H., Bojahr, H., Bolz, O., Contreras, J., Cornils, R., Cortina, J., Denninghoff, S., Fonseca, V., Girma, M., Gonzalez, J., 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, Magnussen, N., Mang, O., Meyer, H., Mirzoyan, R., Moralejo, A., Ona, E., Padilla, L., Panter, M., Plaga, R., Plyasheshnikov, A., Pühlhofer, G., Rauterberg, G., Röhring, A., Rhode, W., Robrade, J., Rowell, G., Sahakian, V., Samorski, M., Schilling, M., Schröder, F., Sevilla, I., Siems, M., Stamm, W., Tluczykont, M., Völk, H. J., Wiedner, C. A., and Wittek, W.

9. 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., Cortina, J., 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.

10. Optimizing the angular resolution of the HEGRA telescope system to study the emission region of VHE gamma rays in the Crab Nebula

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., 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., Kornmeyer, H., Kranich, D., Krawczynski, H., Lampeitl, H., Lorenz, E., Lucarelli, F., Magnussen, N., Mang, O., Meyer, H., Mirzoyan, R., Moralejo, A., Luis Padilla, Panter, M., Plaga, R., Plyasheshnikov, A., Prahl, J., Pühlhofer, G., Rhode, W., Röhring, A., Rowell, G., Sahakian, V., Samorski, M., Schilling, M., Schröder, F., Siems, M., Stamm, W., Tluczykont, M., Völk, H. J., Wiedner, C., and Wittek, W.

11. Search for a TeV gamma-ray halo of Mkn 501

Author

Aharonian, F. A., Akhperjanian, A. G., Barrio, J. A., Bernlöhr, K., Bolz, O., Börst, H., Bojahr, H., Contreras, J. L., Cortina, J., Denninghoff, S., Fonseca, V., 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., Ketter, J., Kohnle, A., Konopelko, A., Kornmeyer, H., Kranich, D., Krawczynski, H., Lampeitl, H., Lorenz, E., Fabrizio Lucarelli, Magnussen, N., Mang, O., Meyer, H., Mirzoyan, R., Moralejo, A., Padilla, L., Panter, M., Plaga, R., Plyasheshnikov, A., Prahl, J., Pühlhofer, 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.

12. J Musculoskelet Neuronal Interact

Author

Dl, Belavý, Bock O, Börst H, Armbrecht G, Gast U, Degner C, Beller G, Soll H, Salanova M, Habazettl H, Heer M, de Haan A, Df, Stegeman, Cerretelli P, Blottner D, Joern Rittweger, Gelfi C, Kornak U, Felsenberg D, Kinesiology, Research Institute MOVE, Molecular cell biology and Immunology, and MOVE Research Institute

Subjects
Adult, Male, Spaceflight, Middle Aged, Vibration, Exercise Therapy, Berlin, Young Adult, Countermeasures, Treatment Outcome, Physical Fitness, Humans, Osteoporosis, Microgravity, Inactivity, Exercise, Functional Neurogenomics [DCN 2], Bed Rest, Weightlessness Simulation, Weltraumphysiologie
Abstract

Contains fulltext : 89007.pdf (Publisher’s version ) (Open Access) Long-term bed-rest is used to simulate the effect of spaceflight on the human body and test different kinds of countermeasures. The 2nd Berlin BedRest Study (BBR2-2) tested the efficacy of whole-body vibration in addition to high-load resisitance exercise in preventing bone loss during bed-rest. Here we present the protocol of the study and discuss its implementation. Twenty-four male subjects underwent 60-days of six-degree head down tilt bed-rest and were randomised to an inactive control group (CTR), a high-load resistive exercise group (RE) or a high-load resistive exercise with whole-body vibration group (RVE). Subsequent to events in the course of the study (e.g. subject withdrawal), 9 subjects participated in the CTR-group, 7 in the RVE-group and 8 (7 beyond bed-rest day-30) in the RE-group. Fluid intake, urine output and axiallary temperature increased during bed-rest (p < .0001), though similarly in all groups (p > or = .17). Body weight changes differed between groups (p < .0001) with decreases in the CTR-group, marginal decreases in the RE-group and the RVE-group displaying significant decreases in body-weight beyond bed-rest day-51 only. In light of events and experiences of the current study, recommendations on various aspects of bed-rest methodology are also discussed. 01 september 2010

13. A search for TeV gamma-ray emission from SNRs, pulsars and unidentified GeV sources in the galactic plane in the longitude range between -2° and 85°

Author

Aharonian, F. A., Akhperjanian, A. G., Beilicke, M., Bernlöhr, K., Bojahr, H., Bolz, O., Börst, H., Coarasa, T., Contreras, J. L., Juan Cortina, 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.

14. 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., Juan Cortina, 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., Los Reyes, R., 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.

15. Reanalysis of the high energy cutoff of the 1997 Mkn 501 TeV energy spectrum

Author

Aharonian, F. A., Akhperjanian, A. G., Barrio, J. A., Bernlöhr, K., Bolz, O., Börst, H., Bojahr, H., Contreras, J. L., Cortina, J., Denninghoff, S., Fonseca, V., 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., Kornmeyer, H., Kranich, D., Krawczynski, H., Lampeitl, H., Lorenz, E., Lucarelli, F., Magnussen, N., Mang, O., Meyer, H., Mirzoyan, R., Moralejo, A., Padilla, L., Panter, M., Plaga, R., Plyasheshnikov, A., Prahl, J., Pühlhofer, G., Rhode, W., Röhring, A., Gavin Rowell, Sahakian, V., Samorski, M., Schilling, M., Schröder, F., Siems, M., Stamm, W., Tluczykont, M., Völk, H. J., Wiedner, C., and Wittek, W.

16. A study of Tycho's SNR at TeV energies with the HEGRA CT-system

Author

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

Subjects
Physics, Photon, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), Hadron, FOS: Physical sciences, HEGRA, Flux, Astronomy and Astrophysics, Astrophysics, law.invention, Telescope, Space and Planetary Science, law, Limit (mathematics), Supernova remnant, Astrophysics::Galaxy Astrophysics, Cherenkov radiation
Abstract

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 of these data, ~65 hours in total, resulted in no evidence for TeV gamma-ray emission. The 3sigma upper limit to the gamma-ray flux (>1 TeV) from Tycho is estimated at 5.78x10^{-13} photons cm^{-2} s^{-1}, or 33 milli-Crab. We interpret our upper limit within the framework of the following scenarios: (1) that the observed hard X-ray tail is due to synchrotron emission. A lower limit on the magnetic field within Tycho may be estimated B>=22 microG, assuming that the RXTE-detected X-rays were due to synchrotron emission. However, using results from a detailed model of the ASCA emission, a more conservative lower limit B>=6 microG is derived. (2) the hadronic model of Drury, Aharonian & Voelk, and (3) the more recent time-dependent kinetic theory of Berezhko & Voelk. Our upper limit lies within the range of predicted values of both hadronic models, according to uncertainties in physical parameters of Tycho, and shock acceleration details. In the latter case, the model was scaled to suit the parameters of Tycho and re-normalised to account for a simplification of the original model. We find that we cannot rule out Tycho as a potential contributor at an average level to the Galactic cosmic-ray flux., 9 pages, 6 figures. Accepted for publication in Astronomy and Astrophysics

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