|Description:|| Extremely Metal-Poor Dwarf Galaxies (XMPs) are the best local analogs of the first generation of low-mass galaxies formed early on, possessing chemical abundances as close as possible to that of the primordial Universe. XMPs are defined as galaxies having ionized gas with an oxygen abundance lower than a tenth of the solar value. They are commonly blue compact dwarfs (BCDs) characterized by blue colors, low luminosity and mass, and compactness. In over 75% of the cases, XMPs exhibit asymmetric optical morphology, associated with a massive and extended HI component. In addition, XMPs are undergoing a burst of star formation, forming stars at a rate similar to high redshift sources. Notwithstanding, the majority of the XMPs appear to be isolated and/or are associated with low-density environments, so that merger/interaction processes are likely not responsible for the XMP properties.|
Instead, it has been suggested that most of the XMP characteristics can be explained through cosmological gas accretion.
In this talk I will present the main results on the multi-wavelength study of XMPs: their characteristics and components, the relations with other galaxy populations and possible explanations for their properties.