Project N
Weighing visible and dark matter with the baryonic Tully-Fisher Relation
Federico Lelli & Chris Harrison
The baryonic Tully-Fisher relation relates the visible mass of a galaxy to its outer rotation velocity, providing insight into the nature of dark matter. We will explore this fundamental relation with new data and stellar population models.
The baryonic Tully-Fisher relation, linking the visible mass of a galaxy to its outer rotation velocity, is one of the tightest relations in extragalactic Astronomy. Its detailed properties (slope, normalization, and scatter) provide a key constraint to galaxy formation models in the standard model of cosmology “Lambda Cold Dark Matter” (LCDM) as well as to alternative theories of gravity. The measurement of the galaxy stellar mass, however, remains a major source of uncertainty. Stellar population synthesis models allow us to relate what we measure (the galaxy luminosity in some photometric band) to what we need to know (the galaxy stellar mass), but different model assumptions lead to different results. The ESO summer student will use multiband data and new stellar population synthesis models to estimate the stellar masses of a large sample of nearby galaxies (the SPARC sample). He/she will then construct different sets of baryonic Tully-Fisher relations using different assumptions (e.g., the galaxy star-formation history, the chemical history, the effects of peculiar stellar evolution phases, etc.) and address the following questions: Which stellar population model gives the smallest scatter? How does this compare with cosmological expectations?
#galaxies #darkmatter #stellarpops #statistics #python
