galaxy evolution

At group meeting, Blanton discussed his results regarding evolution from redshift unity to one tenth, comparing SDSS and DEEP2. He confirms the data result of Bell et al and Faber et al, but not the punchline, because he can show that the uncertainties in the modeling of stellar evolution (and the photometry of galaxies across redshift) are comparable to the evolutionary effects. So, at the moment, merging is not required to explain the evolution in the luminous part of the red sequence.

Jim Peebles (Princeton) gave a great talk about the issues, as he sees them, with extending CDM (well tested on large scales) down to very small scales. He put a lot of emphasis on voids (as usual) and merging. The merging predicted by CDM simulations is indeed hard to reconcile with observations; on the voids his argument is "morphological" rather than statistical. But all this was very timely, because it is exactly what I am working on with NSF proposals, review papers, and research papers, but it was also, as always, solid gold Peebles!

Masjedi, Peebles, and I, in separate pairwise interactions, discussed Masjedi's results and the interpretation of the correlation function in terms of steady-state merging (at small scales). We discussed the issue of whether or not the mean, pairwise, galaxy–galaxy infall velocity dr/dt can be reverse engineered from the correlation function.