Two Classes of Nuclear Profiles |
Sersic fit to low luminosity elliptical (NGC 4464) showing near-nuclear excess. This is termed a "Power Law" or "Coreless" galaxy. [Figures from Kormendy et al 2009 o-link] |
Sersic fit to high luminosity elliptical (NGC 4649) showing near-nuclear loss. This is termed a "Core" galaxy. |
Central profiles matched near the break radius. There is a clear division into those with (cuspy, not flat) cores, and those without (power laws). Notes M32 and M87 are the two prototypes shown with dashed lines. |
The central luminosity density (in Lsun/pc3 at 0.1 arcsec) is much higher for the power-law Ellipticals than for he Core Ellipticals. By definition, the innermost slopes are less in the Core Ellipticals. This illustrates the current (HST) limits of distance probed. [Figure from Lauer et al (1995 o-link) ] |