INTEGRAL (The International Gamma-Ray Astrophysics Laboratory) is the second medium-sized mission of ESA's Horizon 2000 Science Programme. INTEGRAL was launched from Baikonour/Kazachstan in 2002 and is dedicated to the fine spectroscopy and fine imaging of celestial gamma-ray sources in the energy range 15 keV to 10 MeV with concurrent source monitoring in the X-ray (3-35 keV) and optical (V-band, 550 nm) energy ranges.

The INTEGRAL payload consists of the two main gamma-ray instruments, the spectrometer SPI, the imager IBIS and two monitors, the X-ray monitor JEM-X and the optical monitor OMC. All instruments are coaligned, covering simultaneously a very broad energy range for the study of high energy astrophysical sources.

The detection of the very early gamma-emission of a Type Ia supernova (SNIa) could provide a deep insight on the explosion mechanism and nature of the progenitor. The anti-coincidence system (ACS) of INTEGRAL spectrometer SPI can be used to monitor the sky for possible sources, thanks to its omni-directional view and its spectroscopic capabilities.

A new study led by ICE-CSIC and IEEC researchers Mariona Caixach and Jordi Isern, analyses the possibility of using the ACS of the spectrometer SPI on board of the INTEGRAL space observatory for detecting the early gamma-ray emission of an SNIa as a function of the explosion model and distance, as well as of pointing direction.

This study suggests that the ACS is able to detect a supernova in our Galaxy during its early stages at about 6 - 12 days after the explosion. The time of detection depends on the distance of the source, not on its Galactic longitude.