Dear all,
The general Physics colloquia will be given today by Edmond Giraud.
This was arranged after the bulletin was mailed out.
Title and abstract below.
Apologies for the short notice,
Ben
http://www-theorie.physik.unizh.ch/~moore/colloquia.html
Wednesday 9th April, 2003
General Physics Colloquium, 17hr, Y16G05, Irchel
Speaker: Edmond Giraud, Montpellier
Title: The potential of gamma-ray telescopes for dark matter and
cosmology
Abstract:
Cosmological N-body simulations of cold dark matter have revealed the
survival of a large number of substructures within galactic halos.
For what concerns non baryonic matter, physics beyond the standard
model may be supersymmetry. The galactic center (GC) and the dSphs
have long been considered as the best candidates for indirect search
of dark matter either because of its small distance (GC) or of their
huge mass-to-light ratios (dSphs). Probing a large fraction of the
supersymmetric parameter space by assuming that some of the galactic
structures are made of neutralinos is one of the present day major
scientific issues. Ground based gamma-ray telescopes based on
Cerenkov images have the potential of exploring a significant fraction
of the supersymmetric parameter space. A Cerenkov array can also
serve as a major tool in Observational Cosmology and Astrophysics
above 20-30 GeV. The satellite GLAST, which will be launched in 2006,
will provide thousands of $\gamma$-rays sources locations down to a
flux limit of $\rm 10^{-10}~\gamma~cm^{-2}~s^{-1}$, in a year of
observation, which in turn will require a large ground-based
instrument for studying these sources in reasonable exposure
times. The goal of such an instrument will be to see the bulk of the
cosmological AGNs up to z = 3 and to address the question of the
infrared background. The gamma-ray burst afterglows will be observed
with sufficiently high statistics as the high energy emission
declines. This will also provide constraints on some quantum gravity
theories.