We investigate the global photometric scaling relations traced by early-type galaxies in different environments, ranging from dwarf spheroidals, over dwarf elliptical galaxies, up to giant ellipticals (-8 mag > M_V > -24 mag). These results are based
in part on our new HST/ACS F555W and F814W imagery of dwarf spheroidal galaxies in the Perseus Cluster. These scaling relations are almost independent of environment, with Local Group and cluster galaxies coinciding in the various diagrams. We show that at M_V ~ -14 mag, the slopes of the photometric scaling relations involving the Sersic parameters change significantly. We argue that these changes in slope reflect the different physical processes that dominate the evolution of early-type galaxies in different mass regimes. As such, these scaling relations contain a wealth of information that can be used to test models for the formation of early-type galaxies.
We present the results of a Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) study of dwarf galaxies in the core of the rich nearby Perseus Cluster, down to M_V=-12. We identify 29 dwarfs as cluster members, 17 of which are previously u
nstudied. All the dwarfs we examine are remarkably smooth in appearance, and lack internal features. Based on these observations, and the sizes of these dwarfs, we argue that some of the dwarfs in our sample must have a large dark matter content to prevent disruption by the cluster potential. We derive a new method, independent of kinematics, for measuring the dark matter content of dEs, based on the radius of the dwarf, the projected distance of the dwarf from the cluster centre, and the total mass of the cluster interior to it. We find that the mass-to-light ratios of these dwarfs are comparable to those of the Local Group dSphs, ranging between 1 and 120.
New TbFeAs(O,F) and DyFeAs(O,F) superconductors with critical temperatures Tc= 46 and 45 K and very high critical fields over 100 T have been prepared at 1100- 1150C and 10-12 GPa, demonstrating that high pressure may be used to synthesise late rare
earth derivatives of the recently reported RFeAs(O,F) (R = La - Nd, Sm, Gd) high temperature superconductors.
