and we are back from lunch
J. Johnson (LANL) talking about supermassive stars as seeds for supermassive black holes - going to be getting more technical
supermassive star has a gas mass ~ 105 solar masses (as oppesed to few hundredish solar masses for standard Pop III stars that could provide low mass seeds)
form later than Pop III - maybe ~ 4-500 Myr after Big Bang
something like that may be needed for observed high luminosity quasars at redshift > 6.
radiative feedback, still not doing it right
but are we they doing it well enough...?
argues supermasive star formation common at z ~ 8-12
#JWST will tell, if true
Whalen, Heger et al finds disruptive (e+/e- pair) detonation for ~ 50,000 Msun stars (Z?) - http://arxiv.org/abs/1211.1815
if true gives 1055 erg SNe - ~ 10,000 more luminous than nomral type II SNe.
those would be rather IR bright - (NB how fast, incl. 1+z dilation? - check)
also chemical signature
NB - other issue, explosion calculations start with static equilibrium model for zero age assembled star - in reality these cannot be in equilibrium, must be undergoing significant accretion - does that matter for detonation? how fragile are these?
talks about IR signature at Z ~ 20-30 - but, but
argued earlier they formed later than Pop III - so should only be seen at lower z - something wrong here
interesting, if true
Note-to-self - what is He yield in these conjectured events? Check.
Next John Wise (Georgia Tech): black hole seeds from first stars
beautiful graphics - check out the pdf of the slides when they are up on the KITP web
so after a decade of ever improving research we conclude we don't actually know Pop III IMF at all... well, it is definitely tipped to massive-ish
and radiative feedback rears, again, its ugly head
cute plot - with no radiative feedback M_BH incresaes by factor of 100 with radiative feedback M_BH increases by factor of 1.001 or so
naked IMBH floating around halos of proto-galaxies, many such
- sounds familiar - http://arxiv.org/abs/1102.0327
caution - the supermassive stars may not be following sims long enough to see fragmentation - possible post-collapse of core - get fragmentation in angular momentum supported outer parts of proto-supermassive star (Greif et al '12? - check) - what do fragments go into? real interesting if clumps make many lower mass BH already bound to central SMBH - total wishful thinking for grav rad detection... timescales matter, hard problem
Elena Rossi (Leiden) - Connecting growth of galaxies to black hole seeds
Mass loss as critical ingredien to massive BH seed formation
switcheroo, not the talk we were expecting
hmm
ok, I didn't catch that sorry
time for a break
PS: much later - my laptop was being used for couple of talks in last part of session, talk on IMBH/SMBH as analogous to jovian/stellar systems
I blathered on a bit about black holes in globulars and what possible relevance they might have
Melvyn gave a jolly nice talk on runaway collapse in nuclear star clusters and whether (v/c) is a critical parameter - per Davies & Miller etc.
Amy Reines presented latest results on sub million solar mass SMBH in dwarf galaxies in LMC-SMC mass range
there are some
now we rest