On the early evolution of Local Group dwarf galaxy types: star formation and supernova feedback

Bermejo-Climent, J. R.; Battaglia, G.; Gallart, C.; Di Cintio, A.; Brook, C. B.; Cicuéndez, L.; Monelli, M.; Leaman, R.; Mayer, L.; Peñarrubia, J. et al.
Bibliographical reference

Monthly Notices of the Royal Astronomical Society, Volume 479, Issue 2, p.1514-1527

Advertised on:
9
2018
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.
Related projects
Project Image
Numerical Astrophysics: Galaxy Formation and Evolution

How galaxies formed and evolved through cosmic time is one of the key questions of modern astronomy and astrophysics. Cosmological time- and length-scales are so large that the evolution of individual galaxies cannot be directly observed. Only through numerical simulations can one follow the emergence of cosmic structures within the current

Claudio
Dalla Vecchia
Project Image
Numerical Astrophysics: Galaxy Formation and Evolution

How galaxies formed and evolved through cosmic time is one of the key questions of modern astronomy and astrophysics. Cosmological time- and length-scales are so large that the evolution of individual galaxies cannot be directly observed. Only through numerical simulations can one follow the emergence of cosmic structures within the current

Claudio
Dalla Vecchia
A view of our Milky Way galaxy with its close neighbors the Magellanic Clouds
Galaxy Evolution in the Local Group

The objective of this project is to understand the formation and evolution of galaxies of different morphological types, using the many local examples that can be resolved into individual stars, hence performing the so-called "galactic archaelogy". This branch of research is one of the main drivers of major international projects/facilities, such

Carmen
Gallart Gallart
Project Image
Traces of Galaxy Formation: Stellar populations, Dynamics and Morphology

Understanding the formation and evolution of galaxies is one of the key challenges of modern astronomy. Exquisitely detailed analyses of nearby and distant galaxies is now possible with the increasing amount of observational data coming from large facilities. Quality spectroscopic data is also becoming more common for galaxies up to and beyond z ~