Friday, January 27, 2017
2:00 pm

TAPIR Seminar

Three-quarters of the Sky, up to 120 kpc: Mapping the Galactic Halo in 3D with PS1 RR Lyrae Stars
Branimir Sesar, Senior Postdoctoral Researcher, Max Planck Institute for Astronomy (MPIA)

If we could map the Galactic halo structure, substructure, and kinematics with high precision and over a large volume, we could search for the faintest Milky Way satellites, measure the properties of the Galactic dark matter halo, and through comparisons with state-of-the-art simulations, constrain the theory of galaxy formation.

I will present one such map of the Galactic halo, traced using a sample of 45,000 RR Lyrae stars selected from the Pan-STARRS1 (PS1) survey, that covers three-quarters of the sky up to 120 kpc of the Sun. I will describe how I used machine learning to select the above sample from a large, but sparse multiband PS1 dataset, and how I plan to use similar datasets, such as those produced by LSST and ZTF, to study the far side of the Galaxy.

As the first preliminary result, I will present the deepest and widest view of the Sagittarius tidal stream, and demonstrate that the so-called Gemini stream (Drake et al. 2013), is simply a distant part of the Sagittarius stream.

Contact Sheri Stoll sstoll@caltech.edu at 626-395-6608
For more information see TAPIR at Caltech
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