Deborah Lokhorst

Research Scientist and Astronomer at the National Research Council of Canada Herzberg Astronomy & Astrophysics Research Centre .

I use a combination of instrumentation, observation and theoretical astrophysics to investigate galaxy formation and evolution, and the role of dark matter in the universe. I started working with and building instrumentation for the Dragonfly Telephoto Array during my PhD at the University of Toronto and the Dunlap Institute. After graduating in 2021, I have continued working with Dragonfly first as a Herzberg Instrument Science Fellow and now Research Officer at the NRC Herzerg Astronomy & Astrophysics Research Centre in Victora, BC, Canada.

MOTHRA

I am Co-PI of MOTHRA (along with Prof. Pieter van Dokkum at Yale University and Prof. Bob Abraham at the University of Toronto), which is an expansion to the Dragonfly Telephoto Array with the goal of imaging the faintest and largest structure in the Universe, the Cosmic Web. More generally, I am interested in developing new technological methods to tackle astronomical questions which can't be investigated with current facilities. My research in the fields of galactic formation and evolution focuses on the circumgalactic medium and gas flows in and out of galaxies, as a driving force for continuing star formation.

Dragonfly Polarimetry

I am Co-PI Dragonfly Polarimetry along with Prof. Mehrnoosh Tahani at the University of South Carolina, which is the latest evolution of the 48-lens Dragonfly Telephoto Array with polarizing filters installed behind each lens. This upgrade allows us to differentiate between linear polarizations of light, which we will use to investigate the magnetic field and dust grain properties of the Milky Way. We also will be able to separate out the Milky Way foreground from extragalactic targets, opening up a new regime of low surface brightness observations of galaxies.

UVMOS Development

I am Co-Lead of a NRC Small Teams project to develop an ultraviolet multi-object spectrograph for UV space missions, such as CASTOR or HWO. This technology development includes upgraded UV coatings on curved gratings, delta-doped UV CMOS detectors, and digital micromirror devices for picking off the targets from the focal plane.

For a current list of publications, follow this NASA/ADS link.

MOTHRA


MOTHRA: Getting stuck in the Cosmic Web

One of the main mysteries of galaxy evolution is how gas (the majority of which is outside of galaxies and trapped in the "cosmic web") gets into galaxies in order to fuel star formation and sustain galaxy growth. This is a difficult question to tackle due to the near-invisibility of gas outside of galaxies in the intergalactic medium and circumgalactic medium.

In the reigning cosmological theoretical model (lambda-CDM), the cosmic web is the largest structure in the Universe: a foam-like structure of dark matter that dictates where structures made out of "normal" matter, such as planets and stars, will form.

Galaxies form in the nodes of the cosmic web, but the majority of gas (the building block for galaxies) remains in the filaments of the cosmic web (the intergalactic medium). Gas is believed to transition from the filaments to the circumgalactic medium of galaxies, then from there into the galaxies themselves. How these steps happen, though, remains largely a mystery.

By using cosmological, hydrodynamical simulations, such as the EAGLE project, we can make theoretical predications for what the cosmic web looks like (such as pictured on the left) and whether we can image these extremely faint astonomical structures with current or proposed facilities.
We can also compare these predictions to actual observations to place constraints on our knowledge.

The Dragonfly Filter-Tilter

The circumgalactic medium is a large, diffuse structure with extremely low surface brightness emission. This places it squarely in the regime of the Dragonfly Telephoto Array, but instead of stars, Dragonfly needs to be able to observe gas.

The Dragonfly Filter-Tilter enables an optical ultra-narrow bandpass filter to be mounted in front of the optics. In additional the Filter-Tilter has the robotic ability to rotate the filter with respect to incoming light, which shifts the wavelength of light that is allowed through the filter. This allows a larger range of astronomical targets to be investigated with the same filter.

The Circumgalactic and Intergalactic Medium

I am Co-PI and Project Director of MOTHRA - a massive upgrade to the Dragonfly Telephoto Array which is currently underway that will add on this ultra-narrowband imaging capability to Dragonfly. Dragonfly will be expanded to 1140 telephoto lenses, 952 of which will be equipped with Filter-Tilters and ultra-narrow bandpass filters. This expansion to Dragonfly is called MOTHRA. MOTHRA is currently under construction with an anticipated completion date at the end of December 2026. We have already completed almost a third of the array, are close to finishing commissioning observations, and will be beginning our scientific observational campaign in February 2026.

During my PhD, I constructed a pathfinder version of MOTHRA with three lenses, and used it to carry out proof-of-concept imaging of the M81 gorup of galaxies. Using this data, we discovered a giant shell of gas in the outskirts of the M82 galaxy (the "H-alpha Shell" - pictured on the left). Our goal with MOTHRA is to map out the circumgalactic medium of local galaxies to unprecedented depths, going far deeper than these initial results.

Dragonfly Polarimetry

The Dragonfly Telephoto Array is a powerful low surface brightness emission wide-field imager. It was designed and constructed by Prof. Bob Abraham at the University of Toronto and Prof. Pieter van Dokkum at Yale University. With a mosaic design formed by multiplexing 48 Canon Telephoto lenses together, Dragonfly is fully refracting, which enables it to reach an order of magnitude fainter in surface brightness imaging than other facilities. By adding polarizing filters, our goals include:

  • Mapping interstellar and cosmic magnetism via dust extinction
  • Using full-Stokes polarimetry to probe magnetic fields
  • Investigating dust alignment and properties
  • Revealing the 3D structure of high-latitude diffuse clouds
  • Probing fundamental physics such as axion-photon coupling

Developing a UVMOS for Space Missions

We are developing the world's first ultraviolet multi-object spectrograph (UVMOS) for future space missions. This project is a collaboration with the University of Calgary, the University of Colorado Boulder, and the Laboratoire d'Astrophysique de Marseille to mature the key technologies needed for a UVMOS. These technologies will support the scientific goals of CASTOR, a Canadian-led space telescope focused on optical and UV astronomy. CASTOR, led by the NRC, is planned for launch later this decade and is a key part of Canada's Long Range Plan for astronomy.
Looking further ahead, this instrument concept will also be important for NASA's planned Habitable Worlds Observatory in the 2040s, and the technology developed will benefit Canada's growing Earth-observation and commercial space sectors. Over three years, we will design, build, and test a prototype instrument, building on Canada's and NRC's long-standing expertise in developing astronomical spectrographs.

Outreach

Starting during my graduate studies, where I led the graduate student outreach group AstroTours, which runs monthly public outreach events including a public lecture, planetarium shows, observing, and demos, I have enjoyed public outreach, giving regular public talks about current research on research on dark matter, telescopes, and galaxies to a variety of audiences.

A couple of these talks have been recorded and can be watched from these links:

Contact Me

If any of the above interest you, please get in touch!

Email: deborah.lokhorst [at] nrc-cnrc.gc.ca
LinkedIn: www.linkedin.com/in/deblokhorst
Github: github.com/lokhorst
Twitter: twitter.com/DeborahLokhorst