Understanding the mechanism of galaxy growth through a spectroscopic analysis of stellar populations

Dr Ignacio Ferreras

The only way to determine the formation history of a galaxy is through the analysis of its light. A galaxy spectrum encodes a huge amount of information about dynamical state, chemical composition and past star formation history. Hence, the analysis of spectra allows us to backtrack the formation process of galaxies, to understand how they form in relation to intrinsic properties -- such as mass or size -- or to the environment where they live (i.e. field, group or cluster). This PhD project focuses on the analysis of spectroscopic data to extract star formation histories, targeting both nearby and high redshift galaxies, and making use of state-of-the-art models of stellar population synthesis. The methodology involves new multi-variate techniques that optimally extract information from a large volume of data (typically from thousands of galaxy spectra). This timely extension beyond standard measurements of stellar populations will emphasize on the NUV spectral range, which -- in combination with optical information -- will enable us to disentangle the contributions from different stages of the star formation history. The NUV is especially important as very distant, high redshift galaxies, can only be observed in detail in their spectral NUV rest frame.

Cosmic CSI: The spectrum of a galaxy contains the "DNA fingerprint" of its past formation. We will use spectral features similar to those shown in the top panels, to reveal the characteristics of the underlying stellar populations.

 Cosmic CSI: The spectrum of a galaxy contains the "DNA fingerprint" of its past formation. We will use spectral features similar to those shown in the top panels, to reveal the characteristics of the underlying stellar populations.