Bibcode
Graham, A. W.; Trujillo, I.; Erwin, P.
Bibliographical reference
American Astronomical Society Meeting 204, #40.25; Bulletin of the American Astronomical Society, Vol. 36, p.720
Advertised on:
5
2004
Citations
0
Refereed citations
0
Description
We investigate the nuclear and global structure of elliptical galaxies,
and the apparent disparity between the Nuker and Sérsic
light-profile models. We show that the so-called ``power-law" galaxies
in fact have Sérsic r1/n profiles over their entire
observed radial range. Consequently, only three (Sérsic-profile)
parameters are required to simultaneously describe both the inner
(HST-resolved) and outer profiles of low-luminosity (M > -20.5 B-mag)
elliptical galaxies. We also find that ``core galaxies" have
Sérsic profiles with a (partially evacuated) single power-law
core. We have developed a modified (5-parameter) Sérsic profile
with a power-law core to model the complete radial extent of luminous
galaxies with cores. In addition to quantifying the global stellar
distribution in these systems, we have derived new estimates of their
core radii and other central properties. Comparison of the central
stellar deficits with the galaxies' black hole masses suggests that the
number of (dissipationless) major mergers that have produced luminous
elliptical galaxies is around 1-2, rather than 8-10, which agrees with
theory and implies that the galactic merger history of the Universe is
roughly an order of magnitude less violent than previous observational
analyses had suggested.
Support for proposal number HST-AR-09927.01-A was provided by NASA
through a grant from the Space Telescope Science Institute, which is
operated by the Association of Universities for Research in Astronomy,
Inc., under NASA contract NAS5-26555.