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    Multiwavelength Observations of a Flare from Markarian 501

    Catanese, M. and Bradbury, S.M. and Breslin, A.C. and Buckley, J.H. and Carter-Lewis, D.A. and Cawley, Michael F. and Dermer, C.D. and Fegan, D.J. and Finley, J.P. and Gaidos, J.A. and Hillas, A.M. and Johnson, W.N. and Krennrich, F. and Lamb, R.C. and Lessard, R.W. and Macomb, D.J. and McEnery, J.E. and Moriarty, P. and Quinn, J. and Rodgers, A.J. and Rose, H.J. and Samuelson, F.W. and Sembroski, G.H. and Srinivasan, R. and Weekes, T.C. and Zweerink, J. (1997) Multiwavelength Observations of a Flare from Markarian 501. Astrophysical Journal, 487 (L143). ISSN 0004-637X

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    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 gsim 350 GeV) γ-ray observations taken with the Whipple Observatory γ-ray telescope, data from the Oriented Scintillation Spectrometer Experiment of the Compton Gamma Ray Observatory, and quick-look results from the All-Sky Monitor of the Rossi X-Ray Timing Explorer, while EGRET did not detect Mrk 501. Short-term optical correlations are not conclusive, but the U-band flux observed with the 1.2 m telescope of the Whipple Observatory was 10% higher than in March. The average energy output of Mrk 501 appears to peak in the 2-100 keV range, which suggests 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 γ-ray flux observed during this period is the highest ever detected from this object. The VHE γ-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 gsim5 TeV.

    Item Type: Article
    Additional Information: Citation: M. Catanese et al 1997 ApJ 487 L143
    Keywords: BL Lacertae objects: individual; Markarian 501); gamma rays: observations;
    Academic Unit: Faculty of Science and Engineering > Experimental Physics
    Item ID: 9953
    Identification Number:
    Depositing User: Dr. Michael Cawley
    Date Deposited: 18 Sep 2018 16:45
    Journal or Publication Title: Astrophysical Journal
    Publisher: American Astronomical Society
    Refereed: Yes
    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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