EDP Sciences
Free access
Volume 410, Number 1, October IV 2003
Page(s) 389 - 396
Section Physical and chemical processes
DOI http://dx.doi.org/10.1051/0004-6361:20031194

A&A 410, 389-396 (2003)
DOI: 10.1051/0004-6361:20031194

A new template background estimate for source searching in TeV $\gamma$-ray astronomy

G. P. Rowell

Max Planck Institut für Kernphysik, Postfach 103980, 69029 Heidelberg, Germany
(Received 21 May 2003 / Accepted 30 July 2003 )

A new method is described that permits quickly and easily, a 2-dimensional search for TeV $\gamma$-ray sources over large fields of view (~ $6^\circ$) with instruments utilising the imaging atmospheric Cerenkov technique. It employs as a background estimate, events normally rejected according to a cosmic-ray background rejection criterion based on image shape, but with reconstructed directions overlapping the source of interest. This so-called template background model is demonstrated using example data taken with the stereoscopic HEGRA System of Cerenkov Telescopes. Discussion includes comparisons with a conventional background estimate and limitations of the model. The template model is well suited to the search for point-like, moderately extended sources and combinations thereof, and compensates well for localised systematic changes in cosmic-ray background response.

Key words: methods: data analysis -- gamma rays: observations

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