NGC 5128 , a giant elliptical galaxy only \sim 4 Mpc away , is the dominant member of a galaxy group of over 80 probable members .
The Centaurus group provides an excellent sample for a kinematic comparison between the halo of NGC 5128 and its surrounding satellite galaxies .
A new study , presented here , shows no kinematic difference in rotation amplitude , rotation axis , and velocity dispersion between the halo of NGC 5128 , determined from over \sim 340 of its globular clusters , and those of the Centaurus group as a whole .
These results suggest NGC 5128 could be behaving in part as the inner component to the galaxy group , and could have begun as a large initial seed galaxy , gradually built up by minor mergers and satellite accretions , consistent with simple cold dark matter models .
The mass and mass-to-light ratios in the B-band , corrected for projection effects , are determined to be ( 1.3 \pm 0.5 ) \times 10 ^ { 12 } M _ { \sun } and 52 \pm 22 M _ { \sun } /L _ { \sun } for NGC 5128 out to a galactocentric radius of 45 kpc , and ( 9.2 \pm 3.0 ) \times 10 ^ { 12 } M _ { \sun } and 153 \pm 50 M _ { \sun } /L _ { \sun } for the Centaurus group , consistent with previous studies .