Krennrich, F. and Akerlof, C.W. and Buckley, J.H. and Burdett, A.M. and Carter-Lewis, D.A. and Cawley, Michael F. and Catanese, M. and Connaughton, V. and Fegan, D.J. and Finley, J.P. and Gaidos, J.A. and Lamb, R.C. and Lessard, R.W. and McEnery, J.E. and Mohanty, G. and Quinn, J. and Rodgers, A.J. and Rose, H.J. and Schubnell, M.S. and Sembroski, G.H. and Weekes, T.C. and Wilson, C.W. and Zweerink, J. (1997) Detection of Multi-TeV Emission from Markarian 421. Astrophysical Journal, 481 (758). ISSN 0004-637X

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Abstract

Gamma rays with energies exceeding 5 ± 1.5 TeV have been detected from Markarian 421 using the Whipple Observatory's 10 m γ-ray telescope. These observations employ a new technique: the so-called large zenith-angle technique. Because they are taken at large zenith angles, the observations yield high statistics data on the multi-TeV part of the spectrum and are well suited for examining the question of a possible energy cutoff. Observations taken during high states on 1995 June 20, 21, and 28 show no evidence for a spectral break. These results conflict with a previous interpretation of the Markarian 421 energy spectrum in which a cutoff due to γ-ray absorption in extragalactic space was postulated.

Item Type:	Article
Additional Information:	Citation: F. Krennrich et al 1997 ApJ 481 758
Keywords:	BL Lacertae objects : individual; Markarian 421; gamma rays : observations;
Academic Unit:	Faculty of Science and Engineering > Experimental Physics
Item ID:	9949
Identification Number:	https://doi.org/10.1086/304090
Depositing User:	Dr. Michael Cawley
Date Deposited:	18 Sep 2018 15:46
Journal or Publication Title:	Astrophysical Journal
Publisher:	American Astronomical Society
Refereed:	Yes
URI:
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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