Scientific Objectives

Gamma-ray astronomy explores the most energetic phenomena that occur in nature and addresses some of the most fundamental problems in physics and astrophysics. It embraces a great variety of gamma-ray continuum and gamma-ray line processes: nuclear excitation, radioactivity, positron annihilation and Compton scattering; and an even greater diversity of astrophysical objects and phenomena: nucleosynthesis, nova and supernova explosions, the interstellar medium, cosmic-ray interactions and sources, neutron stars, black holes, gamma-ray bursts, active galactic nuclei and the cosmic gamma-ray background. Not only do gamma-rays allow us to see deeper into these objects, but the bulk of the power radiated by them is often at gamma-ray energies.

In the 15 keV - 10 MeV region, line-forming processes such as nuclear excitation, radioactivity, positron annihilation, cyclotron emission and absorption become important, and when used as astrophysical tools, are almost certain to lead to fundamental new discoveries. Unique astrophysical information is contained in the spectral shift, line width, and line profiles. Detailed studies of these processes require the resolving power (E/deltaE = 500) of a germanium spectrometer such as that employed on Integral.

The scientific goals of Integral are addressed through the use of high resolution spectroscopy with fine imaging and accurate positioning of celestial sources in the gamma-ray domain. Fine spectroscopy over the entire energy range permits spectral features to be uniquely identified and line profiles to be determined for physical studies of the source region. The fine imaging capability of Integral within a large field of view permits the accurate location and hence identification of the gamma-ray emitting objects with counterparts at other wavelengths, enables extended regions to be distinguished from point sources and provides considerable serendipitous science which is very important for an observatory-class mission.
The following list of topics are addressed by Integral:

Gamma-Ray Astrophysics before INTEGRAL
1809 keV all-sky map
511 keV map
SN 1987A
Black hole
GRO J1655 lightcurve
Binary Systems

More information and further reading can be found here: see also:
  • the section on Payload (... and more science)
  • the list of INTEGRAL publications.
  • the public outreach pages of ESA

  • the public outreach pages of the ISDC