- [*] Hubble Space Telescope Imaging of Brightest Cluster Galaxies
- Laine S., van der Marel R.P., Lauer T., Postman M., O'Dea C.,
- AJ, 125, 478-505, 2003
this paper in the ADS
We used the HST WFPC2 to obtain I-band images of the centers of 81
brightest cluster galaxies (BCGs), drawn from a volume-limited sample
of nearby BCGs. The images show a rich variety of morphological
features, including multiple or double nuclei, dust, stellar disks,
point source nuclei, and central surface brightness depressions. High
resolution surface brightness profiles could be inferred for 60
galaxies. Of those, 88% have well-resolved cores. Twelve percent of
the BCG sample lacks a well-resolved core; all but one of these BCGs
have ``power-law'' profiles. Some of these galaxies have higher
luminosities than any power-law galaxy identified by Faber et al.
(1997), and have physical upper limits on the break radius well below
the values observed for core galaxies of the same luminosity. These
results support the idea that the central structure of early-type
galaxies is bimodal in its physical properties, but also suggest that
there exist high luminosity galaxies with power-law profiles (or
unusually small cores). The BCGs in the latter category tend to fall
at the low end of the BCG luminosity function and tend to have low
values of the quantity alpha (the logarithmic slope of the metric
luminosity as a function of radius, at 10 kpc). Since theoretical
calculations have shown that the luminosities and alpha values of BCGs
grow with time as a result of accretion, this suggests a scenario in
which elliptical galaxies evolve from power-law profiles to core
profiles through accretion and merging. This is consistent with
theoretical scenarios that invoke the formation of massive black hole
binaries during merger events (Abridged).
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Last modified March 16, 2003.
Roeland van der Marel,