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Title: DARK MATTER CORES IN THE FORNAX AND SCULPTOR DWARF GALAXIES: JOINING HALO ASSEMBLY AND DETAILED STAR FORMATION HISTORIES

We combine the detailed star formation histories of the Fornax and Sculptor dwarf spheroidals with the mass assembly history of their dark matter (DM) halo progenitors to estimate if the energy deposited by Type II supernovae (SNe II) is sufficient to create a substantial DM core. Assuming the efficiency of energy injection of the SNe II into DM particles is ε{sub gc} = 0.05, we find that a single early episode, z ≳ z {sub infall}, that combines the energy of all SNe II due to explode over 0.5 Gyr is sufficient to create a core of several hundred parsecs in both Sculptor and Fornax. Therefore, our results suggest that it is energetically plausible to form cores in cold dark matter (CDM) halos via early episodic gas outflows triggered by SNe II. Furthermore, based on CDM merger rates and phase-space density considerations, we argue that the probability of a subsequent complete regeneration of the cusp is small for a substantial fraction of dwarf-size halos.
Authors:
;  [1] ;  [2]
  1. Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen (Denmark)
  2. Institute of Astronomy, University of Cambridge, Madingley Road, CB3 0HA Cambridge (United Kingdom)
Publication Date:
OSTI Identifier:
22363970
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 782; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DENSITY; DWARF STARS; GALAXIES; MASS; NONLUMINOUS MATTER; PHASE SPACE; PROBABILITY; STAR EVOLUTION; TYPE II SUPERNOVAE