School of Physical and Chemical Sciences Te Kura Matū Seminar Series

Gaia and the Local Dark Matter Density

Speaker

Dr Hamish Silverwood

Institute

Institute of Cosmos Sciences, University of Barcelona, ICCUB

Time & Place

Fri, 31 Aug 2018 11:00:00 NZST in Room 701, Level 7, West Building

All are welcome

Abstract

Dark Matter (DM) is a fundamental element of our cosmos, and there are many experiments searching for its interactions with Standard Model (SM) particles as it passes through detectors here on Earth. These results are then used to explore new physics theories necessary to describe DM, such as supersymmetry, sterile neutrinos, or axions. Yet the interpretation the signal rates from all such experiments require a robust determination of the local DM density - is there a lot of DM around us that interacts very weakly, or a little DM that has a stronger interaction? This local density is determined through analysing the positions and velocities of the stars in the local region of the Milky Way, and so is set to undergo a revolution with recent arrival of Data Release 2 of the Gaia satellite.

To make this local DM density determination with Gaia we have developed a two-dimensional Jeans equation based method which allows for the inclusion of previously neglected dynamical elements. In this talk I will introduce the method and give an update on the ongoing work to apply it to Gaia DR2 data. I will also discuss the disequilibria features found in DR2 such as the ripples in the Milky Way disc caused by the recent passage of the Sagittarius dwarf galaxy. These disequilibria will impact local DM density measurements, and so I will also cover how our method can deal with them.

Note: this seminar was originally scheduled for Friday the 10th of August - but due to unforeseen circumstances has been rescheduled for 31 August 2018

All Welcome

Biography

Hamish completed a Masters of Science here at UC then went on to do his PhD in Amsterdam. He is now based at the Institute of Cosmos Sciences, University of Barcelona, ICCUB