Cutoff in the TeV Energy Spectrum of Markarian 421 during Strong Flares in 2001
/ Authors
F. Krennrich, H. Badran, I. Bond, S. Bradbury, J. Buckley, D. Carter-Lewis, M. Catanese, W. Cui, S. Dunlea, D. Das
and 36 more authors
I. de la Calle Pérez, D. Fegan, S. Fegan, J. Finley, J. Gaidos, K. Gibbs, G. Gillanders, T. Hall, A. Hillas, J. Holder, D. Horan, M. Jordan, M. Kertzman, D. Kieda, J. Kildea, J. Knapp, K. Kosack, M. Lang, S. LeBohec, B. McKernan, P. Moriarty, D. Müller, R. Ong, R. Pallassini, D. Petry, J. Quinn, N. Reay, P. Reynolds, H. Rose, G. Sembroski, R. Sidwell, N. Stanton, S. Swordy, V. Vassiliev, S. Wakely, T. Weekes
/ Abstract
Exceptionally strong and long-lasting flaring activity of the blazar Mrk 421 occurred between 2001 January and March. Based on the excellent signal-to-noise ratio of the data, we derive the energy spectrum between 260 GeV and 17 TeV with unprecedented statistical precision. The spectrum is not well described by a simple power law even with a curvature term. Instead, the data can be described by a power law with exponential cutoff: dN/dE ∝ Ee m-2 s-1 TeV-1 with E0 = 4.3 ± 0.3stat TeV. Mrk 421 is the second γ-ray blazar that unambiguously exhibits an absorption-like feature in its spectral energy distribution at 3-6 TeV.
Journal: The Astrophysical Journal Letters
DOI: 10.1086/324221