Barred Galaxies: an Observer’s Perspective

Summary. I review both well established and more recent findings on the proper-ties of bars, and their host galaxies, stemming from photometric and spectroscopic observations, and discuss how these findings can be understood in terms of a global picture of the formation and evolution of bars, keeping a connection with theoretical developments. In particular, I show the results of a detailed structural analysis of ≈ 300 barred galaxies in the Sloan Digital Sky Survey, providing physical quantities, such as bar length, ellipticity and boxyness, and bar-to-total luminosity ratio, that can either be used as a solid basis on which realistic models can be built, or be com-pared against more fundamental theoretical results. I also show correlations that indicate that bars grow longer, thinner and stronger with dynamical age, and that the growth of bars and bulges is connected. Finally, I briefly discuss open questions and possible directions for future research. 1 Some Basic Facts It is well established now that bars are very often found in disc galaxies. One usually finds a bar fraction of ∼ 2/3 [32], considering both prominen