Wednesday, November 24, 2010 - 3:15pm
Chris Hayward (CFA):
"Combining hydrodynamics and radiative transfer to model high-redshift,dusty galaxies"
Abstract. I will describe our efforts simulating dusty galaxies through a combination of Gadget-2 hydrodynamical simulations and Sunrise dust radiative transfer. The talk will focus on our model for submillimeter-selected galaxies (SMGs), a population of high-redshift (z ~ 1-5), dusty ULIRGs. SMGs are of particular interest because they are among the most rapidly star-forming galaxies known (SFR ~ 100-10^4 solar masses per year), and theoretical models have had difficulty reproducing their observed number densities unless they utilize a top-heavy IMF. I first will discuss what galaxy properties a submm galaxy selection selects for. The SMG selection does not select objects with the highest star formation rate because the relationship between submm flux and star formation rate is very different for quiescent and bursty modes of star formation, making starbursts are not as efficient at boosting submm flux as one might naively think. It is possible to calculate submm flux from SFR and dust mass, but the relationship differs significantly from the commonly used, simple model of a single-temperature, optically-thin modified blackbody. I will also show that our model can reproduce the observed number densities without resorting to a non-standard IMF, contrary to previous claims. One of the main reasons for the agreement is a heretofore unappreciated bimodality in the SMG population. Finally, I will touch on the relationship of SMGs to 24 micron-selected galaxies.