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Putting the Virgo Cluster on the Map

Laura Ferrarese ’95 PhD says she pursued her graduate studies at Johns Hopkins University at just the right time. It was the early 1990s, and the Hubble Space Telescope was sending its first images back to Earth.

“You would get to work in the morning, look at the data that had just been taken, and you knew you were the first person to ever see those kind of details, to ever look at those galaxies with that resolution,” says Ferrarese.  She was particularly fascinated by the early images HST was taking of the Virgo Cluster, the largest collection of galaxies closest to Earth. “No one else had ever seen it. For a few moments, you were the only person in the universe to ever have that kind of experience. It was so exciting, especially for a student.”

Twenty-five years later, Ferrarese is still fascinated by the mysteries of the Virgo Cluster. She now serves as principal investigator for the Next Generation Virgo Cluster Survey (NGVS), a multinational project involving astronomers from 45 universities and research institutes across North and South America, Europe, and Asia.

“It’s a massive undertaking and involved a lot of observing time,” says Ferrarese, whose team spent five years and nearly 1,000 hours of observing time on the Canada-France-Hawaii Telescope on Mauna Kea in Hawaii, between 2009 and 2013. “But we were able to image the cluster in its entirety, very deeply, and with good resolution. By doing this, we were able to discover very faint, small galaxies that up to now had only been detected and studied in the neighborhood of our own galaxy, the Milky Way, or its closest companion, Andromeda. Now we’re exploring a completely different part of the sky in a completely different environment that is over 20 times farther away.”

The project has already yielded fruitful results: Ferrarese says astronomers had only identified approximately 1,600 galaxies in the Virgo Cluster before NGVS, but by using CFHT’s powerful camera over a huge 100-square-degree swath of the sky (an area larger than 500 full moons), researchers have now cataloged more than three times as many previously unseen galaxies. After all the data have been crunched, researchers will have a map of the Virgo Cluster in unprecedented detail.

Laura Ferrarese

Some people like to solve crossword puzzles; I like to solve physics problems,” says astronomer Laura Ferrarese.

[Photo courtesy of NRC-CNRC]

Ferrarese, whose research also focuses on the relation between supermassive black holes and their host galaxies and the expansion rate of the universe, is based in Victoria, Canada, and serves as principal research officer with Herzberg Astronomy and Astrophysics. The organization comprises several dozen astronomers and engineers and is part of the government-sponsored National Research Council of Canada. She is also immediate past-president of the Canadian Astronomical Society, a 400-member professional association that promotes educational opportunities for students and the advancement of astronomy in Canada.

The Italian-born Ferrarese says she was always drawn to science, particularly physics and math. “I liked the challenge of having a problem to solve, when you know there has to be an answer, but you don’t know what the answer is. Some people like to solve crossword puzzles; I like to solve physics problems,” she says.

She earned her PhD from Johns Hopkins in 1995, studying under Research Professor Holland Ford, and taught at Rutgers University before moving to Herzberg 10 years ago. She says her time at Hopkins gave her a big boost in the nascent stages of her career. “It was such a great place to be because of its connection with the telescope,” she says. “The department was then—and is now—such an important hub. There were always so many people visiting. As a student, I ended up knowing so many more people in the field than most people at that stage of their career.”

Ferrarese says that mining the NGVS data will keep her busy for several more years. However, she is already looking at the future, by participating in the design and planning for the next generation of telescopes, such as the Thirty Meter Telescope (that will be built on Mauna Kea, near the CFHT site) and the James Webb Space Telescope, generally seen as Hubble Space Telescope’s successor. As for what kind of science project to tackle next, Ferrarese says that one of the most fascinating results to come out of the NGVS to date was the discovery of an object belonging to the elusive “inner Oort cloud”—the second most distant object known in our solar system. “Arguably, we now know more about the Virgo Cluster than we do about our own solar system,” says Ferrarese. So her future research might bring her closer to home.