A dearth of dark matter in ordinary elliptical galaxies.
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.
Romanowsky
Aaron J
AJ
School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK. aaron.romanowsky@nottingham.ac.uk
Douglas
Nigel G
NG
Arnaboldi
Magda
M
Kuijken
Konrad
K
Merrifield
Michael R
MR
Napolitano
Nicola R
NR
Capaccioli
Massimo
M
Freeman
Kenneth C
KC