2014MNRAS.444..222G -
Mon. Not. R. Astron. Soc., 444, 222-236 (2014/October-2)
Too big to fail in the Local Group.
GARRISON-KIMMEL S., BOYLAN-KOLCHIN M., BULLOCK J.S. and KIRBY E.N.
Abstract (from CDS):
We compare the dynamical masses of dwarf galaxies in the Local Group (LG) to those of haloes in the ELVIS (Exploring the Local Volume in Simulations) suite of Λ cold dark matter simulations. We enumerate unaccounted-for, dense haloes (Vmax ≳ 25 km/s) that became massive enough to have formed stars in the presence of an ionizing background (Vpeak > 30 km/s). Within 300kpc of the Milky Way, the number of these objects ranges from 2 to 25 over our full sample. Moreover, this `too big to fail' count grows when extended to the outer regions of the LG: there are 12-40 unaccounted-for massive haloes in the outskirts of the LG, a region that should be largely unaffected by any environmental processes. According to models that reproduce the LG stellar mass function, all of these missing massive systems should have M{sstarf} > 106M☉. We find, unexpectedly, that there is no obvious trend in the M_*-V_max relation for LG field galaxies with stellar masses in the range of ∼ 105-108M☉. Solutions to the too big to fail problem that rely on ram pressure stripping, tidal effects, or statistical flukes appear less likely in the face of these results.
Abstract Copyright:
© 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society (2014)
Journal keyword(s):
galaxies: haloes - Local Group - cosmology: theory - dark matter
Simbad objects:
22
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