Sky monitoring with ARGO-YBJ

Understand

A sky monitoring at gamma ray energy E > 0.6 TeV has been performed by the full coverage Extensive Air Shower detector ARGO-YBJ, located in Tibet at 4300 m of altitude.

• We monitored 135 galactic and extragalactic gamma ray sources in the sky declination band from -10 to +70 degrees for 424 days, detecting the Crab Nebula and Mrk421 with a significance respectively of 7.0 and 8.0 standard deviations.
• For a set of 11 AGNs known to emit in the TeV energy range, the search has been performed in time scales of 1, 10 and 30 days in order to study possible flaring activities.
• Significant emissions has been observed from Mrk421 in the time scales of 10 and 30 days, during June and March 2008, when the source had a strong activity also observed in the X-rays waveband.