Wrote text in the post-starburst environment paper.
Helped Burles and Tongyan with color pictures of gravitational lenses.
Worked out (yes, it is obvious) that if the merger rate onto LRGs as a function of secondary magnitude is proportional to the luminosity function, then the mass-weighted merger rate will be dominated by galaxies around L-star. If it is going to diverge to the faint end, then the LRG-galaxy cross correlation will be a very strong function of the secondary galaxy magnitude, with dwarfs having much higher amplitude cross-correlation than giants. Doesn't seem likely; in fact I think we know this not to be true. The assertion in Murali et al 2002 that the mass build-up in galaxies is dominated by smooth accretion rather than merger events (is this the work upon which Romeel's assertion is based?) is not very robust, as it involves a huge extrapolation below the mass resolution of the simulation.
It's true that galaxies in SPH simulations gain most of their mass through smooth accretion of gas,
ReplyDeletenot through mergers with pre-existing galaxies. Further, the global history of star formation tracks the global history of gas accretion rather than the merger history. Interesting.
A comment to let my blog's link. The stuff of a daily summary has been interesting for this week, hope it keeps working.
ReplyDeleteTomorrow I hope I can put a raw version of the pictures on-line, I'll send you the link.
And a question: how does the SPH and SAM results compare to each other in the field of "accretion X merger"??
I'm still trying to understand this new Salvador-Sole result about the non-direct-dependency of the properties inside r_s and the halo history. I know he's gonna say lots about it in Paris.
I think the Salvador-Solé results only apply to DM halos, not the galaxies in them, so it isn't directly relevant, although the group-group merger rate is one of our next projects...
ReplyDeleteYou're right, the results of Salvador-Sole SAMs are for DM halos only. I'll take a carefull look at the paper going to Paris and then at his talk.
ReplyDeleteHope the have the pictures tomorrow. Today it was not possible :-)