Discovery of Very High Energy Gamma Rays from 1ES 1218+30.4

Abstract

The MAGIC collaboration has studied the high peaked BL-Lac object\n1ES1218+30.4 at a redshift z = 0.182, using the MAGIC imaging air Cherenkov\ntelescope located on the Canary island of La Palma. A gamma-ray signal was\nobserved with 6.4sigma significance. The differential energy spectrum for an\nenergy threshold of 120GeV can be fitted by a simple power law yielding F_E(E)\n= (8.1+-2.1)*10^-7 (E/250GeV)^(-3.0+-0.4) TeV^-1 m^-2 s^-1. During the six days\nof observation in January 2005 no time variability on time scales of days was\nfound within the statistical errors. The observed integral flux above 350GeV is\nnearly a factor two below the the upper limit reported by the Whipple\nCollaboration in 2003.\n