The Evolution of Heavy Elements in Dwarf Spheroidal Galaxies

Dwarf Spheroidal Galaxies : Keystones of Galaxy Evolution

Dwarf spheroidal galaxies are the most insignificant extragalactic stellar systems in terms of their visibility, but potentially very significant in terms of their role in the formation and evolution of much more luminous galaxies. We discuss the present observational data and their implications for theories of the formation and evolution of both dwarf and giant galaxies. The putative dark matt...

Dwarf Spheroidal Galaxies

Supernova-driven outflows and chemical evolution of dwarf spheroidal galaxies.

We present a general phenomenological model for the metallicity distribution (MD) in terms of [Fe/H] for dwarf spheroidal galaxies (dSphs). These galaxies appear to have stopped accreting gas from the intergalactic medium and are fossilized systems with their stars undergoing slow internal evolution. For a wide variety of infall histories of unprocessed baryonic matter to feed star formation, m...

Dwarf Spheroidal Galaxies in the Virgo Cluster

We present a study of the smallest and faintest galaxies found in a very deep photographic R band survey of regions of the Virgo Cluster, totalling over 3 square degrees, made with the UK Schmidt Telescope. The objects we detect have the same physical sizes and surface brightnesses as Local Group dwarf spheroidal galaxies. The luminosity function of these extremely low luminosity galaxies (down...

The Kinematics of Dwarf Spheroidal Galaxies

I review observational data on the kinematic properties of dwarf spheroidal galaxies in the halo of the Milky Way and beyond. The present data confirm previous claims that these small galaxies have unusually large central velocity dispersions. ‘Simple’ sources of bias such as binary stars, internal atmospheric motions, measurement errors and small sample sizes cannot explain the large dispersio...