DWARF GALAXIES OF THE LOCAL GROUP Mario Mateo KEY WORDS: Stellar Populations, Local Group Galaxies, Photometry, Galaxy Formation, Spectroscopy, Dark Matter, Interstellar Medium Shortened Title: LOCAL GROUP DWARFS Send Proofs To: Mario Mateo Department of Astronomy; University of Michigan Ann Arbor, MI 48109-1090 Phone: 313 936-1742; Fax: 313 763-6317 Email:
[email protected] ABSTRACT The Local Group (LG) dwarf galaxies offer a unique window to the detailed properties of the most common type of galaxy in the Universe. In this review, I update the census of LG dwarfs based on the most recent distance and radial velocity determinations. I then discuss the detailed properties of this sample, including (a) the integrated photometric parameters and optical structures of these galaxies, (b) the content, nature and distribution of their ISM, (c) their heavy-element abundances derived from both stars and nebulae, (d) the arXiv:astro-ph/9810070v1 5 Oct 1998 complex and varied star-formation histories of these dwarfs, (e) their internal kinematics, stressing the relevance of these galaxies to the dark-matter problem and to alternative interpretations, and (f) evidence for past, ongoing and future interactions of these dwarfs with other galaxies in the Local Group and beyond. To complement the discussion and to serve as a foundation for future work, I present an extensive set of basic observational data in tables that summarize much of what we know, and what we still do not know, about these nearby dwarfs. Our understanding of these galaxies has grown impressively in the past decade, but fundamental puzzles remain that will keep the Local Group at the forefront of galaxy evolution studies for some time.