Mission

Science Objectives

Astrophysics aims to provide an understanding of the objects making up our Universe by studying the radiation they emit. INTEGRAL focused on the emission of gamma photons, which are the sign of extremely violent physical phenomena. Detailed studies have provided new insights into the physical characteristics of specific celestial bodies such as supernovae, neutron stars, black holes and active galaxy nuclei, and identified the sources which contribute heavy elements (beyond Helium) to the interstellar environment. Furthermore, the nature of gamma photons is such that they are very difficult to stop, so those that reach us may come from very distant regions, and thus provide a wealth of information on the history of our Universe.

Integral is looking at:

• Compact Objects (White Dwarfs, Neutron Stars, Black Hole Candidates, High Energy Transients and Gamma-Ray Bursts),
• Extragalactic Astronomy (Galaxies, Clusters, AGN, Seyfers, Blazars, Cosmic Diffuse Background),
• Stellar Nucleosynthesis (Hydrostatic Nucleosynthesis (AGB, WR Stars), Explosive Nucleosynthesis (Supernovae, Novae)),
• Galactic Structure (Cloud complex Regions, Mapping of continuum and line emission, ISM, CR distribution),
• The Galactic Centre,
• Particle Processes and Acceleration (Transrelativistic Pair Plasmas, Beams, Jets),
• Identification of High-Energy Sources (Unidentified Gamma-Ray Objects as a Class),
• PLUS: Unexpected Discoveries...

Some Results

SPI image of the Galactic centre region in the 40 - 100 keV band. The transitory source IGR J17461-3213 discovered by Integral could be a good black hole candidate.
ISGRI images of the Galactic Centre in the 20-40 keV band. (Courtesy A. Paizia et al)		ISGRI images of the Galactic Centre in the 40-60 keV band. (Courtesy A. Paizia et al)

Mission

Integral, the international astrophysics laboratory dedicated to the study of gamma-rays, was launched in 2002. Following on from Sigma and the Compton Observatory, Integral not only prolonged their mission but also extended it by discovering new sources. Integral observes with unrivalled spectral resolution and sensitivity the emissions of gamma-rays specific to nuclear reactions leading to the creation of elements within the Universe.

The Integral project (INTErnational Gamma-Ray Astrophysics Laboratory) was given the go-ahead in 1993 by ESA's Space Science Advisory Committee as a medium-class mission of the agency's Horizon 2000 science programme.

Previous missions:

• HEAO-1 (1977)
• HEAO-3 (1979)
• GRANAT-SIGMA (1989)
• CGRO (1991)