The effect of spectral stacking on the information content
This project investigates how stacking resonant-line spectra (e.g. Lyα, Mg II) alters their spectral shape and information content, a key question for interpreting faint circumgalactic emission. By combining radiative-transfer simulations, synthetic spectra, and a dedicated stacking and fitting pipeline, the project will systematically compare the constraints achievable from individual spectra versus stacks.
Electromagnetic radiation is our primary window to observe galaxies and to constrain our theoretical models. In particular, resonant lines such as Lyman-alpha or MgII play a pivotal role in astrophysics as a tool to study low surface brightness region such as the circumgalactic medium. As the detection of a single object is so challenging, it is common practice to perform “stacking” of individual object, thus beating down the noise and enhancing the signal. However, from a theoretical perspective it is unclear what the stacking analysis does to the spectral shape or the information contained in the data. In this project, we will systematically explore the information content of individual spectra versus stacks. To do so, you will run radiative transfer simulations and assemble individual synthetic spectra, perform a stacking analysis, and build a fitting pipeline to obtain the information contained in the stacks.