The Impact of Inhomogeneous Reionization on the Satellite Galaxy Population of the Milky Way - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado




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Abstract: We use the publicly available subhalo catalogs from the Via Lactea simulationalong with a Gpc-scale N-body simulation to understand the impact ofinhomogeneous reionization on the satellite galaxy population of the Milky Way.The large-volume simulation is combined with a model for reionization thatallows us to predict the distribution of reionization times for Milky Way masshalos. Motivated by this distribution, we identify candidate satellite galaxiesin the simulation by requiring that any subhalo must grow above a specifiedmass threshold before it is reionized; after this time the photoionizingbackground will suppress both the formation of stars and the accretion of gas.We show that varying the reionization time over the range expected for MilkyWay mass halos can change the number of satellite galaxies by roughly twoorders of magnitude. This conclusion is in contradiction with a number ofstudies in the literature, and we conclude that this is a result ofinconsistent application of the results of Gnedin 2000. We compare oursatellite galaxies to observations using both abundance matching and stellarpopulation synthesis methods to assign luminosities to our subhalos and accountfor observational completeness effects. Additionally, if we assume that themass threshold is set by the virial temperature Tvir = 8e3K we find that ourmodel accurately matches the vmax distribution, radial distribution, andluminosity function of observed Milky Way satellites for a reionization timezreion = 9.6^{1.0} {-2.1}, assuming that the Via Lacteasubhalo distribution isrepresentative of the Milky Way. This results in the presence of119^{+202} {-50} satellite galaxies.



Autor: Michael T. Busha, Marcelo A. Alvarez, Risa H. Wechsler, Tom Abel, Louis E. Strigari KIPAC

Fuente: https://arxiv.org/







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