Fitting the integrated Spectral Energy Distributions of Galaxies

Fitting the spectral energy distributions (SEDs) of galaxies is an almost universally used technique that has matured significantly in the last decade. Model predictions and fitting procedures have improved significantly over this time, attempting to keep up with the vastly increased volume and quality of available data. We review here the field of SED fitting, describing the modelling of ultraviolet to infrared galaxy SEDs, the creation of multiwavelength data sets, and the methods used to fit model SEDs to observed galaxy data sets. We touch upon the achievements and challenges in the major ingredients of SED fitting, with a special emphasis on describing the interplay between the quality of the available data, the quality of the available models, and the best fitting technique to use in order to obtain a realistic measurement as well as realistic uncertainties. We conclude that SED fitting can be used effectively to derive a range of physical properties of galaxies, such as redshift, stellar masses, star formation rates, dust masses, and metallicities, with care taken not to over-interpret the available data. Yet there still exist many issues such as estimating the age of the oldest stars in a galaxy, finer details ofdust properties and dust-star geometry, and the influences of poorly understood, luminous stellar types and phases. The challenge for the coming years will be to improve both the models and the observational data sets to resolve these uncertainties. The present review will be made available on an interactive, moderated web page (sedfitting.org), where the community can access and change the text. The intention is to expand the text and keep it up to date over the coming years.Comment: 54 pages, 26 figures, Accepted for publication in Astrophysics & Space Scienc

Simulated Moving Bed Strategies and Designs: From Established Systems to the Latest Developments

The simulated moving bed (SMB) technology has evolved significantly since its inception. The appearance of several variants to conventional SMB has led to better performance in productivity and product purity, and lower operating costs, thus creating new opportunities for different applications. This trend is clearly visible in the increasing number of papers and patents published in this field in recent years. This review aims to gather and discuss several modifications and operation modes that have been proposed, from the most well-known Varicol and PowerFeed to the latest Intermittent-SMB and variable external stream systems, giving particular emphasis to innovations and applications of each SMB strategy. SMB valve designs are also covered in this article for their importance in the application of the operation modes discussed, which require ever more flexible units capable of variable switch times, column expandability, zone bypasses, and reduced solvent consumption while still avoiding contamination through line sharing