The early phases of galaxy formation and evolution

I review observations of galaxy formation and evolution from multiwavelength deep field surveys. These programs are designed to detect and study galaxies over a large range of cosmic history, with observations and many different wavelengths, each of which is important for measuring different physical processes at work in evolving galaxies. I begin with some background motivating interest in multiwavelength deep fields, and a short review of energetic processes that result in emission from galaxies in different wavelength/energy ranges. I then give a short summary of major observing facilities that are currently used for multiwavelength deep surveys, and then offer short descriptions of some of the major surveys that have produced much of the data used today by astronomers studying distant galaxy evolution. I continue with an overview of different methods that are commonly used to identify various types of galaxies at high redshift in deep field data sets. Then, for the remainder of the review, I focus on measurements of star formation rates and stellar masses in galaxies, and how they are used to evaluate the history of galaxy growth and evolution. I discuss the ways in which data at different wavelengths are used to infer star formation rates and stellar masses, concentrating on the complementarity of different techniques, as well as their limitations. I then discuss application of these methods for deriving the global history of star formation in the universe. These measurement now push back over more than 13 billion years of cosmic history and portray the rapid early growth of galaxies, and then the long, slow decline of star formation rates to the present era. I discuss recent results on the nature of star formation in galaxies at the peak epoch of galaxy growth, particularly around redshifts of 2, and their implications about the dominant physical processes that shaped the growth of most galaxies from the earliest times to the present day.