Scientific Goals

Astrophysical theories are based on observations made in the radio, infrared, visible, ultraviolet, X-ray and gamma-ray wavelength ranges.

A more detailed observation in one or more of these wavelength ranges makes it possible to check and improve the theories describing a certain cosmic object, or to develop new theories to explain possible new celestial phenomena.

The characteristics of the X-ray detectors on board SAX will make it possible to perform a detailed spectroscopic and variability study of X-ray sources with moderate angular resolution (about 1 arcmin) in the energy range from 0.1 to 300 keV. SAX will collect new data on known X-ray sources in order to verify their astrophysical models, extending measurements over a much wider energy range than previously performed. Moreover, the SAX experiments have a high sensitivity that should allow the detection of new X-ray sources.

Given the instrument capabilities over a wide energy range, SAX can provide a significant contribution (and unique contribution for science involving the exploitation of the wide band) in several areas of X-ray astronomy such as:

• Compact galactic sources; shape and variability of the continuum: narrow spectral features (iron line, cyclotron lines) as a function of the orbital and rotational phases. Ultra-soft sources; discovery and study of X-ray transients;
• Active Galactic Nuclei: spectral shape and dynamics of the variable continuum and of the narrow and broad components from 0.1 to 200 keV in bright objects (soft excess, warm and cold absorption and related O and Fe edges, iron line and high energy bump, high energy cut-off); spectral shape of objects down to 1/20 of 3C273 up to 100-200 keV; spectra of high redshift objects up to 10 keV;
• Clusters of galaxies: spatially resolved spectra of nearby objects and the study of temperature gradients and cooling flows; chemical composition and temperature distribution as a function of redshift;
• Supernova remnants: spatially resolved spectra of extended remnants; spectra of Magellanic Cloud remnants;
• Normal galaxies: spectra from 0.1 to 10 keV of the extended emission;
• Stars: multi-temperature spectra of stellar coronae from 0.1 to 10 keV;

This file was last modified on Wednesday, 02-Sep-1998 17:28:55 CEST by Mauro Orlandini