Free Access
Volume 431, Number 1, February III 2005
Page(s) 197 - 202
Section Interstellar and circumstellar matter

A&A 431, 197-202 (2005)
DOI: 10.1051/0004-6361:20041552

The unidentified TeV source (TeV J2032+4130) and surrounding field: Final HEGRA IACT-System results

F. Aharonian1, A. Akhperjanian2, M. Beilicke3, K. Bernlöhr1, H.-G. Börst4, H. Bojahr5, O. Bolz1, T. Coarasa6, J. Contreras7, J. Cortina8, S. Denninghoff6, V. Fonseca7, M. Girma1, N. Götting3, G. Heinzelmann3, G. Hermann1, A. Heusler1, W. Hofmann1, D. Horns1, I. Jung1, 9, R. Kankanyan1, M. Kestel6, A. Kohnle1, A. Konopelko1, 10, D. Kranich6, H. Lampeitl3, M. Lopez7, E. Lorenz6, F. Lucarelli7, O. Mang4, D. Mazin6, H. Meyer5, R. Mirzoyan6, A. Moralejo7, E. Oña-Wilhelmi7, M. Panter1, A. Plyasheshnikov1, 11, G. Pühlhofer12, R. de los Reyes7, W. Rhode5, J. Ripken3, G. P. Rowell1, V. Sahakian2, M. Samorski4, M. Schilling4, M. Siems4, D. Sobzynska6, 13, W. Stamm4, M. Tluczykont3, 14, V. Vitale6, H. J. Völk1, C. A. Wiedner1 and W. Wittek6

1  Max-Planck-Institut für Kernphysik, Postfach 103980, 69029 Heidelberg, Germany
    e-mail: [Gavin.Rowell;Dieter.Horns]
2  Yerevan Physics Institute, Alikhanian Br. 2, 375036 Yerevan, Armenia
3  Universität Hamburg, Institut für Experimentalphysik, Luruper Chaussee 149, 22761 Hamburg, Germany
4  Universität Kiel, Inst. f. Experimentelle und Angewandte Physik, Leibnizstr. 15-19, 24118 Kiel, Germany
5  Universität Wuppertal, Fachbereich Physik, Gaußstr. 20, 42097 Wuppertal, Germany
6  Max-Planck-Institut für Physik, Föhringer Ring 6, 80805 München, Germany
7  Universidad Complutense, Facultad de Ciencias Físicas, Ciudad Universitaria, 28040 Madrid, Spain
8  Now at Max-Planck-Institut für Physik, Föhringer Ring 6, 80805 München, Germany
9  Now at Washington University, St. Louis MO 63130, USA
10  Now at Humboldt Universität f. Physik, Unter den Linden 6, 10099 Berlin, Germany
11  Altai State University, Dimitrov Street 66, 656099 Barnaul, Russia
12  Now at Landessternwarte Heidelberg, Königstuhl, 69117 Heidelberg, Germany
13  Home institute: University Lodz, Poland
14  Now at Laboratoire Leprince-Ringuet, École Polytechnique, 91128 Palaiseau, France (IN2P3/CNRS)

(Received 29 June 2004 / Accepted 17 September 2004 )

The unidentified TeV source in Cygnus is now confirmed by follow-up observations from 2002 with the HEGRA stereoscopic system of Cherenkov Telescopes. Using all data (1999 to 2002) we confirm this new source as steady in flux over the four years of data taking, extended with radius 6.2 $^\prime$ ( $\pm$ $1.2^\prime_{\rm stat}$  $\pm$ $0.9^\prime_{\rm sys}$) and exhibiting a hard spectrum with photon index  -1.9. It is located in the direction of the dense OB stellar association, Cygnus OB2. Its integral flux above energies E>1 TeV amounts to ~5% of the Crab assuming a Gaussian profile for the intrinsic source morphology. There is no obvious counterpart at radio, optical nor X-ray energies, leaving TeV J2032+4130 presently unidentified. Observational parameters of this source are updated here and some astrophysical discussion is provided. Also included are upper limits for a number of other interesting sources in the FoV, including the famous microquasar Cygnus X-3.

Key words: gamma rays: observations -- stars: early-type -- open clusters and associations: individual: Cygnus OB2

SIMBAD Objects

© ESO 2005

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