PhD colloquium, location: Lecture Hall 0.012 AIfA
Yvonne Fichtner
The impact of stellar feedback on the circumstellar medium and galaxy evolution
Abstract:
Feedback from stars plays a crucial role in the formation and evolution of galaxies, impacting for instance the star formation rate and morphology. Stellar feedback must be incorporated into simulations of galaxies through sub-grid models, which rely on simplifying assumptions. In this talk, I will examine some of these assumptions with the aim to improve sub-grid models.
For this aim, we derive in the first project presented the stellar wind feedback from a grid of massive stellar models, in which we account for stellar rotation, binarity, and different metallicities. Compared to the commonly assumed case of non-rotating single stars, accounting for stellar rotation and binarity can strongly increase the feedback energy from stellar winds, especially at low metallicity. Incorporating stellar winds in a cosmological simulation results in a reduced stellar mass, outflows, and star formation fluctuations of the simulated galaxy. However, a galaxy simulated with feedback from rotating stars and binary systems has properties similar to those of a galaxy simulated with only non-rotating stars, despite the differences in the stellar wind energy.
In a second project, we examine how the circumstellar medium, which is unresolved in galaxy simulations, influences the available stellar feedback at larger scales. We perform 1D simulations of the circumstellar medium, affected by stellar winds, photoionisation and supernova feedback. We find that the circumstellar medium can alter the available feedback in various ways, e.g. by dissipating energy, with the effects being stronger at larger distance from the feedback source.
Finally, we present a preliminary sub-grid feedback model that incorporates the previous results and discuss challenges that the model faces.