Bibcode
Bermejo-Climent, J. R.; Battaglia, G.; Gallart, C.; Di Cintio, A.; Brook, C. B.; Cicuéndez, L.; Monelli, M.; Leaman, R.; Mayer, L.; Peñarrubia, J.; Read, J. I.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 479, Issue 2, p.1514-1527
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9
2018
Citations
22
Refereed citations
20
Description
According to star formation histories (SFHs), Local Group dwarf galaxies
can be broadly classified in two types: those forming most of their
stars before z = 2 (fast) and those with more extended SFHs (slow). The
most precise SFHs are usually derived from deep but not very spatially
extended photometric data; this might alter the ratio of old to young
stars when age gradients are present. Here, we correct for this effect
and derive the mass formed in stars by z = 2 for a sample of 16 Local
Group dwarf galaxies. We explore early differences between fast and slow
dwarfs, and evaluate the impact of internal feedback by supernovae (SNe)
on the baryonic and dark matter (DM) component of the dwarfs. Fast
dwarfs assembled more stellar mass at early times and have larger
amounts of DM within the half-light radius than slow dwarfs. By imposing
that slow dwarfs cannot have lost their gas by z = 2, we constrain the
maximum coupling efficiency of SN feedback to the gas and to the DM to
be ˜10 per cent. We find that internal feedback alone appears
insufficient to quench the SFH of fast dwarfs by gas deprivation, in
particular for the fainter systems. Nonetheless, SN feedback can core
the DM halo density profiles relatively easily, producing cores of the
sizes of the half-light radius in fast dwarfs by z = 2 with very low
efficiencies. Amongst the `classical' Milky Way satellites, we predict
that the smallest cores should be found in Draco and Ursa Minor, while
Sculptor and Fornax should host the largest ones.
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