• gamma ray bursters, support for satellite observations (e.g. SWIFT)stellar variability (e.g. accretion, proto-stellar activity)

Light from many different classes of astronomical objects varies, sometimes periodically and predictably, but often also chaotically. Some objects can change their light output (luminosity) by many orders of magnitude, and in a short period of time (seconds sometimes!). One such recent phenomenon of this nature are gamma ray bursters, probably dense neutron star annihilating themselves in the cores of distant galaxies. The imaging instrument, SALTICAM, plus the imaging mode of PFIS, will be used for such observations, while spectroscopy and spectropolarimetry using PFIS will also be employed to study spectral line variability, giving information on dynamics. For brighter objects, high resolution spectroscopy using the HRS will probe the very structure of spectral lines, leading to very precise measurements of radial velocities, gas dynamics, line asymmetries and abundances.

 

• Magellanic Clouds, nearby dwarf galaxies
• galaxies with different evolution, mergers - interactions - cannibalism

Much of what we understand about the birth, life and death of stars is obtained by studying them as a groups, like in our nearby galaxy neighbours. Likewise we learn a lot about the kinematics and dynamics of such galaxies. The Multi-Object mode of PFIS will be utilized for such observations, as well as imaging spectroscopy with the Fabry-Perot mode.

 

• globular clusters and galaxies
• dark matter searches

The Universe is in motion, whether it is local, like the planets in the Solar System, or stars in our own Milky Way galaxy and other galaxies. Techniques to derive the velocities of hundred or thousands of stars at once can map out these motion and help unravel the mysteries of 'dark matter': that unseen, probably dominant, component of the Universe which we can't directly detect from radiation, but rather infer from its influence on the visible components of the Universe: stars, galaxies and the like. The PFIS instrument will have two modes, Multi-Object Spectroscopy and Fabry-Perot Imaging Spectroscopy, which will target such observations.

 

There are more than 70 planets that have been discovered around other stars, mostly in the Solar neighbourhood. This burgeoning field will be well served by the HRS, which will be capable of high precision radial velocity measurements, to better than 1 metre per second. The queue-scheduled nature of SALT is crucial in obtaining such data over a suitable time base of months to year, which are the orbital period of such planet.