About Me

I am a PhD candidate in the Department of Astronomy and Astrophysics at the University of Toronto. My research, under the supervision of Ray Carlberg, is on using tidal streams to understand the distribution of dark matter around our galaxy. In particular, much of my recent work has focused on observations of the Orphan Stream using DECam.

Research Interests

My research is focused on stellar streams, large tail-like structures formed out of globular clusters or dwarf galaxies which have been tidally stripped by the galactic potential. My interest in tidal streams is primarily for their utility in detecting substructure within the galactic halo. The Lambda Cold Dark Matter (LCDM) cosmological model predicts that we should have a significantly greater population of dwarf galaxies within our galactic potential than we acually see, by nearly two orders of magnitude. This deficit is called the Missing Satellite Problem. One possible resolution is that the clumps of dark matter, called sub-halos, which would have seeded the expected population of dwarf galaxies, simply failed to accumulate enough visible matter to be detectable. However, they would still interact gravitationally, and we would expect dark matter sub-halos to produce detectable gaps within tidal streams, allowing us to indirectly measure the population of sub-halos within the galactic halo. The observation of tidal streams could lead to a solution to the Missing Satellite Problem.

Other Interests


I have a strong interest in education and public outreach. I am routinely involved with the University of Toronto Astronomy Public Tours, which provide a public lecture, rooftop observing, and planetarium shows, on the first Thursday of most months. I have also been a part of Astronomy on Tap T.O, which consists of events at local bars. The aim is to be significantly less formal than our usual tours, and in so doing reach a completely different and new audience. We have three short talks, along with astronomy related bar games with prizes. You can find information about future events here.


On my free time, I volunteer with Pride Toronto. In particular, I'm on the Trans* Pride team. In 2015 I was responsible for planning the first annual Trans* Pride Community Fair. It's primary purpose was to give exhibition space for Ontario grassroots groups run by and for trans people; in particular, small groups and organizations for whom the entrance fees to the standard Pride Streetfair are prohibitive. This fair was the first of its kind in Toronto, being preceded in Canada (to my knowledge) only by the TransSask Gender Fair, in Regina.


Office: AB 203 (Astronomy Building on the St. George Campus)

E-mail: hetherington at astro dot utoronto dot ca

Mailing Address:
Lauren Hetherington
Department of Astronomy and Astrophysics
50 St. George Street Room 101
Toronto, ON, Canada
M5S 3H4