Multiwavelength Observations of a Flare from Markarian 501
Abstract
We present multiwavelength observations of the BL Lacertae object Markarian 501 (Mrk 501) in 1997 between April 8 and April 19. Evidence of correlated variability is seen in very high energy (VHE, E > 350 GeV) gamma-ray observations taken with the Whipple Observatory gamma-ray telescope, data from the Oriented Scintillation Spectrometer Experiment of the Compton Gamma-Ray Observatory, and quicklook results from the All-Sky Monitor of the Rossi X-ray Timing Explorer while the Energetic Gamma-Ray Experiment Telescope did not detect Mrk 501. Short term optical correlations are not conclusive but the U-band flux observed with the 1.2m telescope of the Whipple Observatory was 10% higher than in March. The average energy output of Mrk 501 appears to peak in the 2 keV to 100 keV range suggesting an extension of the synchrotron emission to at least 100 keV, the highest observed in a blazar and ~100 times higher than that seen in the other TeV-emitting BL Lac object, Mrk 421. The VHE gamma-ray flux observed during this period is the highest ever detected from this object. The VHE gamma-ray energy output is somewhat lower than the 2-100 keV range but the variability amplitude is larger. The correlations seen here do not require relativistic beaming of the emission unless the VHE spectrum extends to >5 TeV.
Keywords
Cite
@article{arxiv.astro-ph/9707179,
title = {Multiwavelength Observations of a Flare from Markarian 501},
author = {M. Catanese and S. M. Bradbury and A. C. Breslin and J. H. Buckley and D. A. Carter-Lewis and M. F. Cawley and C. D. Dermer and D. J. Fegan and J. P. Finley and J. A. Gaidos and A. M. Hillas and W. N. Johnson and F. Krennrich and R. C. Lamb and R. W. Lessard and D. J. Macomb and J. E. McEnery and P. Moriarty and J. Quinn and A. J. Rodgers and H. J. Rose and F. W. Samuelson and G. H. Sembroski and R. Srinivasan and T. C. Weekes and J. Zweerink},
journal= {arXiv preprint arXiv:astro-ph/9707179},
year = {2009}
}
Comments
10 pages, 2 figures, accepted for publication in ApJ Letters