IMPROVEMENT OF GAMMA-HADRON DISCRIMINATION AT TEV ENERGIES USING A NEW PARAMETER, IMAGE SURFACE BRIGHTNESS

The recent advances in TeV gamma-ray astronomy using imaging Cerenkov telescopes is mainly due to the good separation between the properties of gamma-ray and hadronic showers. A new method for this discriminati on is described. The method is mainly based on the change of the image 's Size and Surface Brightness (Size/Area) with energy and the differe nces in these parameters between those initiated by gamma-rays and had rons. The application of the method to the Whipple's 10 m telescope da tabase from the Crab Nebula and Markarian 421 demonstrates its sensiti vity to gamma-hadron separation. This study shows the importance of th e image Surface Brightness, in addition to the previously used Shape a nd Orientation parameters. (C) 1997 Elsevier Science B.V.