University of Connecticut

Events Calendar

Astronomy Seminar

Friday, February 1, 2019
12:30pm – 1:30pm

Storrs Campus
Gant West 103B

Dr. Shea Garrison-Kimmel, Einstein Postdoctoral Fellow, TAPIR, Caltech

Dark matter and galaxy formation in the Local Group

Simulations show that an expanding universe where luminous galaxies trace a massive underlying web of dark matter -- an unknown type of mass whose only strong interaction is via gravity -- reproduce a wide variety of large-scale observations spectacularly well. However, basic questions remain within the model, including the nature of dark matter and the small-scale physics important to galaxy formation. Our cosmic neighborhood, the Local Group (LG), is one of the best laboratories for answering these vital questions. Because the LG contains both our galaxy, the Milky Way, and a similarly-sized neighbor, Andromeda, it provides an unprecedented viewpoint on relatively high-mass galaxy evolution. Moreover, tiny and faint dwarf galaxies, which have historically presented "problems" within the model, are only observationally accessible within the LG. I demonstrate how zoom-in simulations yield insights into the formation of the Milky Way and Andromeda, and how they reveal these so-called small-scale problems that relate to the number and internal structure of dwarf galaxies in the LG. I culminate by presenting new simulations of the LG that incorporate well-motivated prescriptions for galaxy micro-physics (e.g. star formation and stellar feedback), then discuss how these micro-physics combine to successfully reproduce the dwarf galaxies around the Milky Way. However, these new simulations also highlight how the wide variety in the structure of the dwarf galaxies around Andromeda could present a new challenge to the model, pointing either to the standard model physics neglected in the simulations or new dark matter physics.


Profs. T. Blum and J. Trump

Physics Department (primary)

Control Panel