Unraveling galaxy evolution: connecting physical processes to their observational signatures
Event date
Tjitske Starkenburg
Northwestern University
Event Type

The formation and evolution of galaxies bridges fundamental physics from small to large scales. As such, all internal and external effects that shape a galaxy’s evolution together determine its present-day properties. But the individual physical processes in some cases may leave distinctive observational signatures, for example bursts of star formation or (temporary) quenching, the formation of bulges and bars, changes in metallicity or age gradients, warps, outflows and much more. Disentangling these signatures and the evolutionary physics that caused them is one of the main challenges in the field, and can provide crucial insight into the underlying physics.

In this talk I will discuss a few different approaches to this challenge. One interesting avenue consists of studying uncommon galaxies and uncovering the unique evolutionary pathways that made them outliers in the present-day galaxy population. Galaxies with distinct kinematic components are one example of these outliers that exhibit (very) clear signatures of evolutionary processes. I will highlight how the combined power of IFU surveys and large-scale galaxy simulations may be able to use these dynamical signatures to gather insights about the galaxies’ past.

Additionally, much can be learned from large statistical samples. In the IQ-collaboratory we explore star formation and quiescence of galaxies in large observational datasets and in 6 large-scale cosmological simulations. We carefully build synthetic galaxy spectra for all (~3e5) simulated galaxies, including survey-specific selection functions and noise, and (re)measure observational properties. Using this wealth of spectral data, we describe the galaxy populations in theoretical predictions, mock observations, and observational data, compare these populations. Moreover, we utilize our forward modeling approach to infer the dependence of dust attenuation curves on galaxy properties.  

A third approach to disentangling galaxy formation physical processes based on observational signatures is to make novel predictions for current and upcoming surveys and explore how theoretical assumptions affect the observables. I will show an example of this approach by way of predicting the observability of tidal debris around external (dwarf) galaxies in future surveys.

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