Published in:

Astrophysical Journal 610,1 (2004) 156-160;


We present results from observations taken with the Whipple 10 m very high energy gamma-ray telescope with maximal sensitivity at 400 GeV during 39 hr between 2000 and 2003 in the direction of the giant radio galaxy M87. Using the entire data set, we derive a 99% confidence level upper limit on the flux of gamma-ray emission above 400 GeV from M87 to be less than or equal to 6: 9; 10(-1)2 cm(-2) s(-1). This suggests variability at the 90% confidence level when compared to the flux measured by the HEGRA collaboration in 1999 if the differential spectrum is steeper than a power law of index 3.75. Our search for a correlation between the Rossi X-Ray Timing Explorer all-sky monitor observation and a potential gamma-ray signal is inconclusive.


galaxies : active;; galaxies : individual (m87);; gamma rays : observations;; tev gamma-rays;; bl-lacertae object;; high-resolution;; galaxy m-87;; lac object;; jet;; emission;; spectrum;; radio;; polarization

Date of this Version

January 2004



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