"Together we can observe/model the galaxy!"
Once again this weeks FLTs (Friday Lunchtime Talks) continued the trend of high quality presentations of which there have been several lately and that I've got used to in the XGal Group at Durham.
Geach (Durham) gave a very sexy little number on "Exploring the z > 1 Universe with WFCAM near-IR narrowband surveys", essentially describing how with a sleak H2S1 narrow-band filter, his team is going after a nice big sample of z~2.2 galaxies in the COSMOS and Subaru Deep Fields via locating H-alpha. Very nice. There was claims also for potentially discovering z~9 galaxies (since this is where Ly-alpha would fall in their narrow-band) but with a K-band limiting magnitude of "only" 20.5, I wasn't sure how this was going to work unless lensing comes into play again (which of course this lot are world experts!).
Almeida's (Durham) talk I was really looking forward to as it was on "The properties of Luminous Red Galaxies in hierarchical galaxy formation model". Superb! Essentially Almeida has run simulations with GALFORM using two different models. There is the Baugh et al. (2005) model (with top-heavy IMFs among its many features) and the Bower et al. (2006) model (with AGN feedback incorporated). These two models predict a wide range of galaxy properties and they can be compared to those observed from the SDSS at z~0.24 (see eg the v. nice paper by Barber et al. ) and then at redshift z~0.5 (where good ol' 2SLAQ is in its prime).
For me, the bottom line is this. Both models do a pretty good job on most properties (e.g. Luminosity functions, stellar mass, ages) with the Baugh model probably being "truer" to real life. A couple of properties, metalicity and for me, the z~0.5 clustering don't quite seem to completely line up, but the reproduction tio the Masjedi et al. (2006) result is mega-impressive. This suggests that there is/can be more than one LRG per halo.
Geach (Durham) gave a very sexy little number on "Exploring the z > 1 Universe with WFCAM near-IR narrowband surveys", essentially describing how with a sleak H2S1 narrow-band filter, his team is going after a nice big sample of z~2.2 galaxies in the COSMOS and Subaru Deep Fields via locating H-alpha. Very nice. There was claims also for potentially discovering z~9 galaxies (since this is where Ly-alpha would fall in their narrow-band) but with a K-band limiting magnitude of "only" 20.5, I wasn't sure how this was going to work unless lensing comes into play again (which of course this lot are world experts!).
Almeida's (Durham) talk I was really looking forward to as it was on "The properties of Luminous Red Galaxies in hierarchical galaxy formation model". Superb! Essentially Almeida has run simulations with GALFORM using two different models. There is the Baugh et al. (2005) model (with top-heavy IMFs among its many features) and the Bower et al. (2006) model (with AGN feedback incorporated). These two models predict a wide range of galaxy properties and they can be compared to those observed from the SDSS at z~0.24 (see eg the v. nice paper by Barber et al. ) and then at redshift z~0.5 (where good ol' 2SLAQ is in its prime).
For me, the bottom line is this. Both models do a pretty good job on most properties (e.g. Luminosity functions, stellar mass, ages) with the Baugh model probably being "truer" to real life. A couple of properties, metalicity and for me, the z~0.5 clustering don't quite seem to completely line up, but the reproduction tio the Masjedi et al. (2006) result is mega-impressive. This suggests that there is/can be more than one LRG per halo.
The theoretical sizes seems to give the biggest headache for these models as the sizes of the simlutaed galaxies are still (substantially) underestimated. All in all, when this gets polished off and finished, I think it's gonna be a VERY nice piece of work. BTW, this all still fits in with the "the most massive galaxies formed early on and have done v. little since" idea which I'm now (along with many others) convinced by.
On a more general note, the continued "Observers vs. Theory" rhetoric sometimes pisses me off - and each side is as bad as the other. Lucey (Durham) is one of the main protaginists for the "the theorists just fiddle their models to get the right answer" while comments such as those from Frenk (Durham) of "the simulations will tell you the right answer" is equally as annoying! Surely it's the synergy between observation and theory (and instrumentation) that make the group at Durham so powerful. Baugh, Almeida, Wake and myself have greatly benefitted from the discussions from both sides of the aisle.
Finally, on much more mundane methods, I re-submitted Ross et al. on Friday (yay!), though did not post to astro-ph as intended (boo!). The refs comments and suggestions have ended up being v. helpful and hoepfully have turned a good paper in to a great one (tee hee hee!! ;-)
On a more general note, the continued "Observers vs. Theory" rhetoric sometimes pisses me off - and each side is as bad as the other. Lucey (Durham) is one of the main protaginists for the "the theorists just fiddle their models to get the right answer" while comments such as those from Frenk (Durham) of "the simulations will tell you the right answer" is equally as annoying! Surely it's the synergy between observation and theory (and instrumentation) that make the group at Durham so powerful. Baugh, Almeida, Wake and myself have greatly benefitted from the discussions from both sides of the aisle.
Finally, on much more mundane methods, I re-submitted Ross et al. on Friday (yay!), though did not post to astro-ph as intended (boo!). The refs comments and suggestions have ended up being v. helpful and hoepfully have turned a good paper in to a great one (tee hee hee!! ;-)
posted by NPR at 1:43 PM
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