Dartmouth Events

Physics & Astronomy-Astronomy Seminar - Emily Charles, Ph.D., Univ. of Surrey

Title: "Andromeda 25 - A Dwarf Galaxy with a Low Central Dark Matter"

Monday, September 19, 2022
2:30pm – 3:30pm
Wilder 115
Intended Audience(s): Public
Categories: Arts and Sciences, Lectures & Seminars


The most successful model of the Universe to date is the Lambda Cold Dark Matter Model (LCDM). Theoretical predictions from LCDM on large scales closely match observational evidence.  However, on small scales (e.g. galactic scales) long-standing tensions between theory and observation exist. Dwarf galaxies are dark matter-dominated systems, making them powerful probes for studying dark matter on small scales. Recently I have been focusing on Andromeda 25 (And 25), a dwarf satellite galaxy of M31. And 25 was previously identified in Collins et al (2013) as an outlier with little-to-no dark matter content.  However, this conclusion was heavily caveated due to the small sample size of only 26 stars. With the inclusion of new spectroscopic data, we more than doubled the sample size. In this talk, I will discuss the revised kinematic results of And 25 to find out if it truly is a dwarf galaxy with no dark matter component. I will then expand the discussion to include results from the dynamical mass modeling of And 25 to investigate its unusual dark matter profile and potential explanations for its low central dark matter density.

Via Zoom:


Meeting ID: 939 3499 8150
Passcode: 939471


For more information, contact:
Tressena Manning

Events are free and open to the public unless otherwise noted.