iSIMBA (investigating Stars In the Milky way with Bayesian statistics and Asteroseismology) is a research group in astrophysics at Aarhus University led by Víctor Aguirre Børsen-Koch.

One of the most fundamental problems in astrophysics today is to understand the formation and evolution of galaxies, including our own. The first step to reconstruct the history of the Milky Way is by using models of galactic evolution, which are simplified descriptions of what we believe were the key physical processes at play during the formation and evolution of the Galaxy. In order to properly constrain these models and understand our Galactic past, their predictions need to be compared with accurate properties of stellar populations measured in different regions of the Milky Way.

In the era of large surveys, photometric and spectroscopic data have become available for thousands of stars in our Galaxy. International coordinated efforts such as RAVE, Gaia-ESO, APOGEE, and GALAH have determined their photospheric properties, while the Gaia mission is accurately measuring their positions and distances. These results, if coupled to accurate determination of stellar ages, have the potential to provide a new benchmark to calibrate models of galactic evolution in different regions of the Milky Way and reveal the main physical processes that have shaped our Galaxy into what we see today.

For this purpose, our group has developed the most complete and versatile pipeline for accurate determination of stellar properties using asteroseismology: the BAyesian STellar Algorithm, BASTA (Silva Aguirre et al. 2015, Aguirre Børsen-Koch et al. 2022). BASTA uses precomputed grids of evolutionary models and performs a global search for the optimal solution using a Bayesian approach, and has become the pipeline of choice for a variety of studies in the fields of stellar structure and evolution,  asteroseismology, exoplanet research, and Galactic archaeology. Currently, BASTA is being adapted to form the foundation of the pipeline to determine stellar propertier in the ESA PLATO mission. 

iSIMBA is a part of the Stellar Astrophysics Centre (SAC) – a Centre of Excellence funded by the Danish National Research Foundation.