Detection of High-Energy Gamma-Ray Emission from the Globular Cluster 47
  Tucanae with Fermi
  Globular clusters are known to harbour a significant population of neutron
star X-ray binaries that could be responsible for delaying the inevitable core
collapse of these dense clusters. As a result, their progeny, namely
millisecond pulsars, are also present in large numbers. Following the
confirmation using the Fermi Gamma-ray Space Telescope that millisecond pulsars
are indeed gamma-ray emitters, we report on the detection of the Galactic
globular cluster 47 Tuc with the Fermi Large Area Telescope. This is the first
detection of a Galactic globular cluster in the gamma-ray domain. The gamma-ray
spectrum is consistent with gamma-ray emission from a population of millisecond
pulsars. The observed gamma-ray luminosity implies an upper limit of 60
millisecond pulsars present in 47 Tucanae.
