A Dearth of Dark Matter in Ordinary Elliptical Galaxies

  title={A Dearth of Dark Matter in Ordinary Elliptical Galaxies},
  author={Aaron J. Romanowsky and Nigel G. Douglas and Magda Arnaboldi and Konrad Kuijken and Michael R. Merrifield and Nicola R. Napolitano and Massimo Capaccioli and Kenneth C. Freeman},
  pages={1696 - 1698}
The kinematics of the outer parts of three intermediate-luminosity elliptical galaxies were studied with the Planetary Nebula Spectrograph. The galaxies' velocity-dispersion profiles were found to decline with the radius, and dynamical modeling of the data indicates the presence of little if any dark matter in these galaxies' halos. This unexpected result conflicts with findings in other galaxy types and poses a challenge to current galaxy formation theories. 
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