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SUMMARY:The coupling between the core/cusp and missing satellite problems 
 - Sergey Koposov (University of Cambridge)
DTSTART:20121026T103000Z
DTEND:20121026T113000Z
UID:TALK41295@talks.cam.ac.uk
CONTACT:Sergey Koposov
DESCRIPTION:We calculate the energy that baryons must inject in cold dark 
 matter (CDM) haloes in order to remove centrally-divergent DM cusps on sca
 les relevant to observations of dwarf spheroidal galaxies (dSphs). We esti
 mate that the CDM haloes often associated with the Milky Way's dSphs (M_vi
 r \\sim 10^9-10^) require \\Delta(E) \\sim 10^53-55^ erg in order to form 
 cores on scales comparable to the luminous size of these galaxies. While s
 upernova type II (SNeII) explosions can in principle generate this energy\
 , the actual contribution is limited by the low star formation efficiency 
 implied by the abundance of luminous satellites. Considering that CDM's we
 ll-known `core/cusp' and `missing satellite' problems place opposing deman
 ds on star formation efficiencies\, existing observational evidences for l
 arge cores in the most luminous dSphs require that CDM models invoke some 
 combination of the following: (i) efficient (of order unity) coupling of S
 NeII energy into dark matter particles\, (ii) star formation histories pea
 king at unexpectedly high redshifts (z>6)\, (iii) a top-heavy stellar IMF\
 , and/or (iv) substantial satellite disruption or other stochastic effects
  to ease the substructure abundance constraints. Our models show that the 
 tension between CDM problems on small scales would increase if cored DM pr
 ofiles were to be found in fainter dwarves. \n\nBased on Penarrubia\, Ponz
 en\, Walker\, Koposov (2012) arXiv:1207.2772
LOCATION:Kavli LMR\, IoA
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