Astronomy Lunch Series
Chengyu Xi
Department
of
Physics
&
Astronomy
University
of
Waterloo
Despite the great success of the standard LCDM model in predicting and explaining the large-scale structure of the universe and its evolution, it still faces challenges at smaller scales (< 1 Mpc). Dwarf galaxies seem to be the main “victims”. Their total number within the virial radius of the Milky Way is only observed to be around 50 (including the tiniest ones, with masses of only 300 solar masses), which is much lower than the thousands of potential objects predicted by LCDM. Dwarf "housing conditions" are also a matter of debate, as they seem to occupy smaller subhalos than expected.
To find out whether the theoretical expectations about small-scale structure are just wrong, or whether some mysterious evil force has been brutally suppressing the dwarfs, we need to survey more dwarf populations outside our Local Group. I will present the method we used to assess nearby populations, and present some of the results of our investigations.