A black hole 4 million times more massive than our sun, called Sagittarius A* and pictured here in an artist's impression, is at the center of our Milky Way. (Image: NASA)
A black hole 4 million times more massive than our sun, called Sagittarius A* and pictured here in an artist’s impression, is at the center of our Milky Way. (Image: NASA)

The astronomy professor has been awarded a Radcliffe Institute fellowship to explore the edges of known physics by looking at black holes and exchanging ideas with scientists, artists and filmmakers at Harvard University.

Daniel Stolte, University Relations – Communications

June 1, 2016

The Radcliffe Institute for Advanced Study at Harvard University has selected Dimitrios Psaltis, a professor in the University of Arizona’s Steward Observatory, as a Radcliffe Institute fellow. Together with 54 other women and men, Psaltis is in the 2016–2017 fellowship class at the institute, where the acceptance rate to the fellowship program this year was just under 4 percent. 

Dimitrios Psaltis is interested in testing Einstein’s Theory of General Relativity outside of the comparably tame conditions found in our solar system, so he he has turned to the universe’s ultimate proving grounds: neutron stars and black holes, the astrophysical systems with the strongest gravitational fields we know of.

EXTRA INFO

Dimitrios Psaltis is among fewer than 4 percent of applicants who were accepted to Harvard’s Institute for Advanced Study. The Radcliffe Institute has awarded more than 800 fellowships since its founding in 1999. The full list of fellows is online at www.radcliffe.harvard.edu/fellows2016, as is a new video of previous fellows discussing the impact of their Radcliffe Institute experience on their lives and work: www.radcliffe.harvard.edu/video/fellowship-experience-radcliffe-institute.  

As the 2016–2017 Shutzer Fellow, Psaltis will pursue an individual project at Radcliffe, in a community dedicated to exploration and inquiry across disciplinary boundaries. In addition to receiving the funding, time and space for up to a year of focused work, the fellows — scholars, scientists and artists — benefit from access to Harvard’s libraries and from engaging Harvard undergraduates as research partners.

Some black holes, like this one in a far-away galaxy called M87, shoot out jets of matter at nearly the speed of light. (Image: NASA/STScI/AURA)
Some black holes, like this one in a far-away galaxy called M87, shoot out jets of matter at nearly the speed of light. (Image: NASA/STScI/AURA)

Psaltis joins an international group of fellows coming to the institute from Africa, Asia, Australia, Europe and South America, as well as from across North America. During the year, fellows will present their work in lectures and in gallery exhibitions, many of which are open to the public and shared online.

“What is incredible about the fellowship is that it is not specific to science,” Psaltis said. “The majority of the fellows aren’t scientists but artists like writers and filmmakers. They put us together in the same building with access to all sorts of resources. We will interact and try to explain to each other what we do to people who are not involved in science or the technical aspects of it.”

Psaltis is excited about the prospect of such “intellectual collisions” and the new ideas they might bring not only to his research, but also to the ways he and his colleagues talk to the public. A large part of his work involves creating scientifically accurate, visual simulations of black holes and their surroundings, such as accretion disks, accumulations of matter swirling around the black hole before getting sucked into it.

“Being around filmmakers, for instance, who do this for a living, and trying to explain to them what we do to get input from them about how we visualize those things and make them accessible to the generable public is not something you can easily achieve sitting in an astronomy department somewhere,” Psaltis said.

The UA's Submillimeter Telescope on Mount Graham is one of many linked together to form the Event Horizon Telescope, a virtual telescope as big as Earth. Psaltis and his colleagues are getting ready to use the EHT to take an image of the black hole at the center of the Milky Way and compare it to others, such as the one in M87. (Photo courtesy of Dave Harvey)
The UA’s Submillimeter Telescope on Mount Graham is one of many linked together to form the Event Horizon Telescope, a virtual telescope as big as Earth. Psaltis and his colleagues are getting ready to use the EHT to take an image of the black hole at the center of the Milky Way and compare it to others, such as the one in M87. (Photo courtesy of Dave Harvey)

Psaltis will focus on his work on the Event Horizon Telescope, or EHT, a global network of telescopes linked to function as if it were one Earth-size observatory. Expected to be fully operational for the first time in April 2017, the EHT is poised to peer through the gas and dust of our Milky Way to observe the supermassive black hole suspected to be at the galaxy’s center.

Together with his colleague and wife, Feryal Ozel, who was a 2012-2013 Radcliffe Fellow, Psaltis is heavily involved in developing the simulations and tools for interpreting the data the telescope will collect, and piecing together the image of the black hole.

The timing is perfect, Psaltis said, as he will be at the center of the action of Harvard’s brand-new Black Hole Initiative, an interdisciplinary program designed specifically to research black holes. The program is housed in vicinity of the Radcliffe Institute on Harvard Square.

“The Black Hole Initiative follows a similar concept to the Radcliffe Institute in that it gathers people with a wide range of expertise related to the astrophysics of black holes, the EHT, string theory and even philosophy of science,” he said. “The idea is to put all the people in the same place with the resources they need and students and postdocs around them, to see what can be achieved out of this confluence of expertise. I hope this will result in ways of seeing things in ways that we don’t normally look at.”

The EHT teams both at the UA and the Harvard-Smithsonian Center for Astrophysics will be working together continuously, trying to merge the activities that are going on in both places in order to maximize the output of the science experiment.

All EHT components are in place and ready, Psaltis said. 

“Every single station in the array has been outfitted with the equipment that is required — for example, detectors, atomic clocks, et cetera,” he said. “We successfully completed an engineering dry run last month to make sure everything is working.”

If everything goes well, next April will be the first time that every single telescope in the array will turn to the black hole and we will begin to observe and collect data.

The EHT’s main targets are two very different black holes. One is the black hole in the center of our own galaxy, the Milky Way, and the other is the central black hole estimated to be a thousand times more massive than ours, in a different galaxy called M87.

“The black hole in M87 has one of the most brilliant, long jets that you can see,” Psaltis said, referring to an outflow of matter and energy that spouts from the galaxy’s central black hole into space over a distance of 4,900 light-years.

“The jet goes way, way out of the host galaxy,” he added, “and it’s clearly launched by the black hole itself. Our black hole, on the other hand, has no evidence for any jet or any big outflow like that.”

The EHT scientists are gearing up to actually see the shadow of the black hole that is cast on the emission around it, and measure its properties, which will allow them to learn whether Einstein’s predictions are valid near a black hole.

“The other important thing we want to do is compare a wimpy black hole like ours to a powerful one like the one in M87,” Psaltis said. “There are so many unanswered questions in accretion physics, which is the physics of how black holes gain their mass and grow in size. For example, what happens to the magnetic field near the black hole? Are magnetic fields responsible for launching the jets? What produces the jets? Does most of the matter fall into the black hole or does it get ejected?

“This will be the very first time that we will be able to see those processes happening very close to the black hole and take pictures in real time of how those processes work.”