RSAA Colloquia / Seminars / Feast-of-Facts: Thursday, 29 March 2018, 11:00-12:00; Duffield Lecture Theatre

Benjamin Forrest

"Using Composite Spectral Energy Distributions to Characterize Galaxy Populations at z=1-4"

With increasing sample sizes and multiwavelength photometric coverage of distant galaxies through surveys such as CANDELS, NMBS, and ZFOURGE, the available data at high redshift has grown significantly in the last decade. By de-redshifting and scaling photometry of many tens to hundreds of galaxies with similar spectral energy distributions, we can create low resolution spectra (R~50), quantifying features such as emission line equivalent widths with more precision than possible for a single galaxy without spectroscopy. In this talk I will detail the use of this method with about 7000 high signal to noise galaxies from the ZFOURGE survey. This allows us to identify and characterize populations of galaxies in the green valley, which show morphologies, dust content, and star formation rates between those of star-forming and quenched populations. I will also discuss those galaxies with extreme nebular emission in the young universe, which may be analogs to those which played a role in cosmic reionization.