Hindawi Publishing Corporation Advances in Astronomy Volume 2010, Article ID 158568, 25 pages doi:10.1155/2010/158568 Review Article Star Formation Histories of Dwarf Galaxies from the Colour-Magnitude Diagrams of Their Resolved Stellar Populations Michele Cignoni1, 2 and Monica Tosi2 1 Astronomy Department, Bologna University, Via Ranzani 1, 40127 Bologna, Italy 2 Osservatorio Astronomico di Bologna, INAF, Via Ranzani 1, 40127 Bologna, Italy Correspondence should be addressed to Michele Cignoni,
[email protected] Received 5 May 2009; Accepted 12 August 2009 Academic Editor: Ulrich Hopp Copyright © 2010 M. Cignoni and M. Tosi. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In this tutorial paper we summarize how the star formation (SF) history of a galactic region can be derived from the colour- magnitude diagram (CMD) of its resolved stars. The procedures to build synthetic CMDs and to exploit them to derive the SF histories (SFHs) are described, as well as the corresponding uncertainties. The SFHs of resolved dwarf galaxies of all morphological types, obtained from the application of the synthetic CMD method, are reviewed and discussed. To summarize: (1) only early-type galaxies show evidence of long interruptions in the SF activity; late-type dwarfs present rather continuous, or gasping, SF regimes; (2) a few early-type dwarfs have experienced only one episode of SF activity concentrated at the earliest epochs, whilst many others show extended or recurrent SF activity; (3) no galaxy experiencing now its first SF episode has been found yet; (4) no frequent evidence of strong SF bursts is found; (5) there is no significant difference in the SFH of dwarf irregulars and blue compact dwarfs, except for the current SF rates.