skip to main content

SciTech ConnectSciTech Connect

Title: The study of TeV variability and the duty cycle of Mrk 421 from 3 Yr of observations with the milagro observatory

TeV-flaring activity with timescales as short as tens of minutes and an orphan TeV flare have been observed from the blazar Markarian 421 (Mrk 421). The TeV emission from Mrk 421 is believed to be produced by leptonic synchrotron self-Compton (SSC) emission. In this scenario, correlations between the X-ray and the TeV fluxes are expected, TeV orphan flares are hardly explained, and the activity (measured as duty cycle) of the source at TeV energies is expected to be equal to or less than that observed in X-rays if only SSC is considered. To estimate the TeV duty cycle of Mrk 421 and to establish limits on its variability at different timescales, we continuously observed Mrk 421 with the Milagro observatory. Mrk 421 was detected by Milagro with a statistical significance of 7.1 standard deviations between 2005 September 21 and 2008 March 15. The observed spectrum is consistent with previous observations by VERITAS. We estimate the duty cycle of Mrk 421 for energies above 1 TeV for different hypotheses of the baseline flux and for different flare selections and we compared our results with the X-ray duty cycle estimated by Resconi et al. The robustness of the results is discussed.
Authors:
; ;  [1] ; ; ;  [2] ;  [3] ; ; ;  [4] ;  [5] ;  [6] ; ; ;  [7] ;  [8] ; ;  [9] ;  [10] ;  [11] more »; « less
  1. Department of Physics and Astronomy, Michigan State University, 3245 BioMedical Physical Sciences Building, East Lansing, MI 48824 (United States)
  2. Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States)
  3. Santa Cruz Institute for Particle Physics, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States)
  4. Department of Physics, University of Maryland, College Park, MD 20742 (United States)
  5. Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States)
  6. Department of Physics, Pennsylvania State University, University Park, PA 16802 (United States)
  7. Group P-23, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States)
  8. Department of Physics and Astronomy, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States)
  9. Instituto de Astronomía, Universidad Nacional Autónoma de México, D.F., México 04510 (Mexico)
  10. NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
  11. Department of Physics, Michigan Technological University, Houghton, MI 49931 (United States)
Publication Date:
OSTI Identifier:
22351404
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 782; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BL LACERTAE OBJECTS; COMPARATIVE EVALUATIONS; CORRELATIONS; EMISSION; GAMMA RADIATION; HYPOTHESIS; SPECTRA; STARS; SYNCHROTRON RADIATION; TEV RANGE; X RADIATION