Speaker
Markus Ackermann
(DESY)
Description
The data collected by the Fermi Large Area Telescope (LAT) over the last 3 years
enable a huge step forward in measuring and understanding the origins of the
extragalactic diffuse gamma-ray background (EGB). The EGB originates from the
superposition of different populations of unresolved sources with possible
contributions from genuinely diffuse and exotic processes. In most parts of the
sky it is sub-dominant to the Galactic diffuse emission, which represents a
foreground to be subtracted to allow a measurement of the EGB intensity.
Due to the long exposure, an improved event selection, better understanding of
the Galactic diffuse foregrounds and the charged particle backgrounds, we can
now extend the measurement of the spectrum of the EGB to the energy range
between 100 MeV and several hundred GeV. Additionally, population studies
based on resolved LAT sources allow to constrain the contribution of individual
classes of unresolved sources to the EGB.
Author
Markus Ackermann
(DESY)
