Dark force connects galaxies far, far away
Astronomers at the University of Waterloo have been able to capture the first composite image of a dark matter bridge that connects galaxies together.
The composite image, which combines a number of individual images, confirms predictions that galaxies across the universe are tied together through a cosmic web connected by dark matter that has until now remained unobservable.
Dark matter filaments bridge the space between galaxies in this false colour map. The locations of bright galaxies are shown by the white regions and the presence of a dark matter filament bridging the galaxies is shown in red.
Dark matter, a mysterious substance that comprises around 25 per cent of the universe, doesn’t shine, absorb or reflect light. It has traditionally been largely undetectable, except through gravity.
“For decades, researchers have been predicting the existence of dark-matter filaments between galaxies that act like a web-like superstructure connecting galaxies together,” said Mike Hudson, a professor of astronomy at the University of Waterloo. “This image moves us beyond predictions to something we can see and measure.”
As part of their research, Hudson and co-author Seth Epps, a former master’s student at the University of Waterloo, used a technique called weak gravitational lensing. It's an effect that causes the images of distant galaxies to warp slightly under the influence of an unseen mass such as a planet, a black hole, or in this case, dark matter. The effect was measured in images from a multi-year sky survey at the Canada-France-Hawaii Telescope.
They combined lensing images from more than 23,000 galaxy pairs located 4.5 billion light-years away to create a composite image or map that shows the presence of dark matter between the two galaxies. Results show the dark matter filament bridge is strongest between systems less than 40 million light-years apart.
“By using this technique, we’re not only to able to see that these dark matter filaments in the universe exist, we’re able to see the extent to which these filaments connect galaxies together,” said Epps.
Co-op student gets faculty mentorship opportunity
By Naz Kittani
On her very first work term, 2A Kinesiology co-op student Donna Fok combined her two passions: science and athletics. Fok worked as a research assistant for Applied Health Sciences Professor Jack Callaghan. Also cross-listed with the Faculty of Engineering, Callaghan is a Canada Research Chair in spine biomechanics and injury prevention. With expertise in biomechanics, ergonomics and injury mechanics, Callghan’s supervision helped Fok build a strong foundation for future work terms.
“As a Research Assistant (RA), I supported the graduate theses and studies occurring in Professor Jack Callaghan’s Spine Biomechanics Lab,” explains Fok. “When experiments began, my role included outfitting the participant, collecting data and performing data analysis to determine descriptive findings on lower back discomfort and muscle activation.”
Although assisting with experiments was a major perk of her work term, it was the opportunity to learn in the workplace that Fok valued the most. “Working in research places a major emphasis on learning, which in my opinion was the best aspect of this position. While I was doing my job as an RA, I was encouraged to learn about biomechanics and procedures within the field. I learned by shadowing other graduate students, reading published literature on the topics, or simply by inquiring and participating in studies,” says Fok.
Fok credits this role for helping her choose a career path. “This experience has directed me toward wanting an occupation that focuses on the mechanics of human muscles and bones,” she says. “One field of interest is forensics biomechanics; I’m fascinated by the role of biomechanics in determining the cause of injury and impact.”
To find out more about Professor Callaghan’s research, watch his graduate student research video.
Governor General to visit campus for book launch; other notes
The University of Waterloo will welcome His Excellency the Right Honourable David Johnston, Governor General of Canada and Tom Jenkins, Chair of the Board of OpenText Corporation and Chancellor of the University of Waterloo for a discussion and book signing of their co-written volume Ingenious: How Canadian Innovators Made the World Smarter, Smaller, Kinder, Safer, Healthier, Wealthier, and Happier.
The event takes place on Tuesday, April 25 at 8:30 a.m. in the Sedra Design Centre in Engineering 5. Seats are limited on a first come, first served basis. Copies of the book will be available for sale at the event and the UW Bookstore. This event will also be livestreamed.
The Bombshelter Pub is open this week on weekdays from 11:00 a.m. to 3:00 p.m. if you are looking for lunch in all the wrong places.
The Library has announced that the term loan date has changed from May 15 to September 15, 2017.
The term loan date change went into effect on Tuesday, April 18. Borrowers can now begin renewing their books for the Spring term after this date. Renewal reminder notices will be sent to our patrons on Thursday, April 20.