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Astron. Astrophys. 346, 913-921 (1999)

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Phase-resolved TeV gamma-ray characteristics of the Crab and Geminga pulsars

F. Aharonian 1, A.G. Akhperjanian 7, J.A. Barrio 2,3, K. Bernlöhr 1,8, H. Bojahr 6, J.L. Contreras 3, J. Cortina 3, A. Daum 1,10, T. Deckers 5, S. Denninghoff 2, V. Fonseca 3, J.C. Gonzalez 3, G. Heinzelmann 4, M. Hemberger 1,10, G. Hermann 1,11, M. Heß 1,10, A. Heusler 1, W. Hofmann 1, H. Hohl 6, D. Horns 4, A. Ibarra 3, R. Kankanyan 1, M. Kestel 2, O. Kirstein 5, C. Köhler 1, A. Konopelko 1, H. Kornmeyer 2, D. Kranich 2, H. Krawczynski 1,4, H. Lampeitl 1, A. Lindner 4, E. Lorenz 2, N. Magnussen 6, H. Meyer 6, R. Mirzoyan 2, A. Moralejo 3, L. Padilla 3, M. Panter 1, D. Petry 2,6,9, R. Plaga 2, A. Plyasheshnikov 1, J. Prahl 4, G. Pühlhofer 1, G. Rauterberg 5, C. Renault 1, W. Rhode 6, A. Röhring 4, V. Sahakian 7, M. Samorski 5, D. Schmele 4, F. Schröder 6, W. Stamm 5, H. Völk 1, B. Wiebel-Sooth 6, C. Wiedner 1, M. Willmer 5 and H. Wirth 1

1 Max-Planck-Institut für Kernphysik, Postfach 103980, D-69029 Heidelberg, Germany
2 Max-Planck-Institut für Physik, Föhringer Ring 6, D-80805 München, Germany
3 Universidad Complutense, Facultad de Ciencias Físicas, Ciudad Universitaria, E-28040 Madrid, Spain
4 Universität Hamburg, II. Institut für Experimentalphysik, Luruper Chaussee 149, D-22761 Hamburg, Germany
5 Universität Kiel, Institut für Experimentelle und Angewandte Physik, Leibnitzstr. 15, D-24118 Kiel, Germany
6 Universität Wuppertal, Fachbereich Physik, Gaussstrasse 20, D-42097 Wuppertal, Germany
7 Yerevan Physics Institute, Alikhanian Br. 2, 375036 Yerevan, Armenia
8 Now at Forschungszentrum Karlsruhe, P.O. Box 3640, D-76021 Karlsruhe, Germany
9 Now at Universidad isica d'Altes Energies, E-08193 Bellaterra, Autónoma de Barcelona, Institut de F Spain
10 Now at SAP AG, Postfach 1461, D-69185 Walldorf, Germany
11 Now at Enrico Fermi Institute, University of Chicago, 933 East 56th Street, USA

Received 13 November 1998 / Accepted 19 March 1999


The Crab and Geminga pulsars were observed with the HEGRA stereoscopic IACT-System. A search for phase-resolved time structure of TeV gamma emission was carried out for both pulsars. No evidence for pulsed emission was observed. Geminga shows up as a TeV quiet object in our data. Upper limits were derived in units of the observed DC TeV Crab flux. The 3[FORMULA] upper limit on DC TeV emission of Geminga is 13.0% of the Crab flux. Upper limits on pulsed emission were derived for the phase intervals which revealed pulsed emission in the EGRET 30 MeV - 10 GeV data. The 3[FORMULA] upper limits on pulsed emission in these phase intervals are [FORMULA]2.3% and [FORMULA]7.2% of the Crab DC flux for the Crab and Geminga pulsars, respectively.

Key words: stars: pulsars: individual: Crab – stars: pulsars: individual: Geminga – gamma rays: observations

Send offprint requests to: andreas.daum@sap-ag.de

© European Southern Observatory (ESO) 1999

Online publication: June 17, 1999