Sunday, January 30, 2011

Supermassive Black Holes

Two v interesting papers in Nature by John Kormendy about the growth of super-massive black holes in galaxies.

Jim Peebles in a commentary says "I would not ignore the possibility that the cosmological model requires fine adjustment to account for a relatively small detail — the galaxies."

I'm particularly interested in supermassive black holes in the middle of galaxies because it seems to me that the dependence of E[HELP] on lambda may relate to them. It seems plausible that HELPs are only likely to exist in the arms of spiral galaxies, because there are far too many violent events at and near the galactic centre for the 5bn years or so of stability that appears to be required. It's intuitively clear that increasing lambda will increase the ratio of stars in arms to stars in the centre. Thus from

#HELP = (#HELP/#ArmStars)*(#ArmStars/#SpiralGalaxies)*#SpiralGalaxies

if (#HELP/#ArmStars) doesn't depend on lambda we could get at ∂log(#HELP)/∂Λ from ∂log(#armStarts/#SpiralGalaxies)/∂Λ and ∂log(#SpiralGalaxies)/∂Λ {I am of course including barred spiral galaxies in this category}.

Spiral Galaxies are also rare at the centres of galactic clusters but these probably have too many violent events as well.

No comments: