CORES AND THE KINEMATICS OF EARLY-TYPE GALAXIES
- National Optical Astronomy Observatory, P.O. Box 26732, Tucson, AZ 85726 (United States)
I have combined the Emsellem et al. ATLAS{sup 3D} rotation measures of a large sample of early-type galaxies with Hubble Space Telescope based classifications of their central structure to characterize the rotation velocities of galaxies with cores. 'Core galaxies' rotate slowly, while 'power-law galaxies' (galaxies that lack cores) rotate rapidly, confirming the analysis of Faber et al. Significantly, the amplitude of rotation sharply discriminates between the two types in the -19 > M{sub V} > -22 domain over which the two types coexist. The slow rotation in the small set of core galaxies with M{sub V} > -20, in particular, brings them into concordance with the more massive core galaxies. The ATLAS{sup 3D} 'fast-rotating' and 'slow-rotating' early-type galaxies are essentially the same as power-law and core galaxies, respectively, or the Kormendy and Bender two families of elliptical galaxies based on rotation, isophote shape, and central structure. The ATLAS{sup 3D} fast rotators do include roughly half of the core galaxies, but their rotation amplitudes are always at the lower boundary of that subset. Essentially, all core galaxies have ATLAS{sup 3D} rotation amplitudes {lambda}{sub R{sub e/2}}{<=}0.25, while all galaxies with {lambda}{sub R{sub e/2}}>0.25 and figure eccentricity >0.2 lack cores. Both figure rotation and the central structure of early-type galaxies should be used together to separate systems that appear to have formed from 'wet' versus 'dry' mergers.
- OSTI ID:
- 22086443
- Journal Information:
- Astrophysical Journal, Vol. 759, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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