hide
Free keywords:
-
MPINP:
HESS - Abteilung Hofmann
Abstract:
This work studies the population of Galactic gamma-ray sources between 10 GeV
and 50 TeV. In the first part the data taken by the H.E.S.S. Galatic Plane Survey
(HGPS) above 200 GeV is re-analysed using a Poisson Maximum Likelihood based
detection method. In this process a catalog of gamma-ray sources as well as a
model of the large-scale emission in the Galaxy is created. In total 78 individual
sources are detected, of which 31 can be clearly identified. For the remaining objects
possible associations with known pulsar wind nebulae, supernova remnants and
energetic pulsars are listed. The investigation of the whole source population reveals
a variety of objects, that cover a size range from point source up to radii 1. The
measured fluxes range from 0.6% to 103% of the flux of the Crab Nebula. The
analysis of the longitude, latitude and Log N – Log S distribution of the sources shows
a picture of the population that is compatible with the distribution of energetic
pulsars, supernova remnnants and CO Gas in the Galaxy. The completeness of this
picture is currently limited by the sensitivity of the telescopes. In the second part of
this work the results from the HGPS analysis are systematically compared to high
energy observations of the Fermi-LAT satellite. For this purpose images in three
energy bands are computed (10 - 30 GeV, 30 -100 GeV und 100 - 2000 GeV) from the
Fermi-LAT data and combined into colored RGB images. The qualitative comparison
of the images as well as image-based flux profiles against the HGPS measurement
shows good agreement in many regions. Individual regions with differences are then
discussed in detail. The systematic measurement of fluxes of HGPS sources in the
range between 10 GeV and 2 TeV yields significant emission for 55 objects, among 9
objects previously not known as GeV sources. A detailed examination of those cases
shows source confusion on the GeV side as limiting factor for the detection.
