Letter to the Editor

The INTEGRAL/IBIS scientific data analysis^*

¹ CEA Saclay, DSM/DAPNIA/SAp, 91191 Gif-sur-Yvette Cedex, France
² IASF/CNR, sezione di Bologna, via Gobetti 101, 40129 Bologna, Italy
³ School of Physics and Astronomy, University of Southampton, Highfield, SO17 1BJ, UK
⁴ Integral Science Data Center, Chemin d'Écogia, 16, 1290 Versoix, Switzerland

Corresponding author: A. Goldwurm, agoldwurm@cea.fr

Received: 16 July 2003
Accepted: 10 September 2003

Abstract

The gamma-ray astronomical observatory INTEGRAL, succesfully launched on 17th October 2002, carries two large gamma-ray telescopes. One of them is the coded-mask imaging gamma-ray telescope onboard the INTEGRAL satellite (IBIS) which provides high-resolution (≈12') sky images of in the energy range from 15 keV to 10 MeV with typical on-axis sensitivity of ≈1 mCrab at 100 keV (3σ, 10⁶ s exposure). We report here the general description of the IBIS coded-mask imaging system and of the standard IBIS science data analysis procedures. These procedures reconstruct, clean and combine IBIS sky images providing at the same time detection, identification and preliminary analysis of point-like sources present in the field. Spectral extraction has also been implemented and is based on simultaneous fitting of source and background shadowgram models to detector images. The procedures are illustrated using some of the IBIS data collected during the inflight calibrations and present performance is discussed. The analysis programs described here have been integrated as instrument specific software in the Integral Science Data Center (ISDC) analysis software packages currently used for the Quick Look, Standard and Off-line Scientific Analysis.