The poor things, with their intense levels of gravity, their light-eating tendencies, and their ability to deform space and time, are seen as the monsters of the cosmos, acting like vacuum cleaners and sucking up anything in their path.
But really, they’re just like any other galactic object, says the astronomer, a new assistant professor of physics in the College of Liberal Arts and Sciences. And their outflows – or as he calls them, “burps” – could be really important to the formation of galaxies.
“You think of them as this cosmic villain, but they may have a positive role in distributing elements through a galaxy,” he says. That can lead to the evolution of new planets, and perhaps new life.
With interests in the birth and growth of black holes, stars, and galaxies, three astronomers landed at the UConn Department of Physics this fall, and have begun sharing their love of the cosmos through a new program in astrophysics.
Trump and fellow assistant professors of physics Cara Battersby and Kate Whitaker are working to offer new astrophysics courses, get students involved in astronomy research, and mentor undergraduate and graduate students.
“We are really eager to get students built up with a core foundation in astrophysics,” says Whitaker. “I’m excited about building the astronomy program here.”
When black holes burp
Despite supermassive black holes’ bad reputation, nearly every galaxy has one in its center, and Trump wants to know more about them.
Using the Hubble Space Telescope and the Sloan Digital Sky Survey, Trump, who comes to UConn from a Hubble Fellowship at Penn State University, observes supermassive black holes in distant galaxies and examines the hole’s edge, or its event horizon.
He watches how the hole can build or tear down its surrounding galaxy through outflows from the active and chaotic area outside the event horizon, called its accretion disk. Matter that doesn’t fall in can get spit forcefully out, propagating through empty space, says Trump.
“It may do things like sweep up gas, which might have otherwise collapsed down to form new stars,” he says. “So it may quench star formation.”
On the other hand, elements need to travel through space to start new galaxies, so perhaps black holes could contribute to the formation of new distant galaxies over time, he says.
Galaxies may also control their black holes, he says, by feeding them only occasional tidbits of matter, not letting them “gorge themselves.”
“There’s some sort of weird control going on here, and we don’t yet understand the physics behind it,” he says.
Red and dead
When a galaxy stops forming stars, astronomers call it “red and dead,” for the long-wavelength light it emits. But how galaxies enter this quiescent stage remains a mystery, says Whitaker, currently a Hubble Fellow at UMass Amherst.
It could be due to the galaxy’s supermassive black hole, radiating energy and keeping things too hot to form stars. Or the galaxy could have lost most of its gases – maybe via burps from its black hole – that are essential to star formation.
Recently, Whitaker has discovered distant, ancient galaxies in the process of shutting down, and she will begin collecting data from one such galaxy in January.
Using space telescopes is like using a time machine, Whitaker says, because much of the light they detect was emitted billions of years ago. The upcoming James Webb Space Telescope, set to launch in October 2018, will be the most powerful space telescope of its kind, says Whitaker. It will help researchers observe events that occurred closer to the beginning of the universe – more than 12.7 billion years ago – than has ever been observed. Astronomers poetically call this era “cosmic dawn.”
“James Webb is so exciting because it will allow us to really look at the first mature galaxies, at the peak epoch of star formation,” she says.
The Milky Way experiment
Star formation is a fundamental physical process that creates many of the elements that make up new stars, planets, and even life itself, says Battersby.
“Without stars, we would never have people,” she says.
Astronomers’ predictions about star formation have turned out to be wrong, which drives one of Battersby’s research directions.
“The process of forming a star involves collecting a lot of material, and that’s what gravity does, it’s an attractive force,” she says. “What opposes that is the internal pressure of the gas, and that depends on the environment. This environmental dependence hasn’t been tested in a lot of detail.”
As a National Science Foundation Fellow at the Harvard-Smithsonian Center for Astrophysics, she is leading the largest survey ever conducted to the center of the Milky Way galaxy, where the gas is much denser, and the pressure and temperature are different, than they would be in than they are in our solar neighborhood.
Using data from the Submillimeter Array on the summit of the dormant Mauna Kea volcano in Hawaii, her team is looking at is looking at long-wavelength light from very cold regions, which has the potential to soon form stars.
“Astronomers don’t have a laboratory where we can create a star in one environment and create a star in another environment, and see what changes,” she explains. “Luckily the universe is a really big place, so any experiment you can think of is probably happening somewhere. You just have to find it.”
Cosmic dawn at UConn
Even before setting foot on campus this fall, the new faculty began receiving emails from enthusiastic UConn students about classes and research.
“Both the undergraduate and graduate students are very excited because they have been requesting such a program at UConn for a long time,” says Nora Berrah, Department Head of Physics. “Thanks to the support of Dean Teitelbaum, the physics department is elated to have been able to hire these three outstanding astronomers.”
As part of a plan to eventually create an astrophysics major, the new faculty will add an undergraduate Modern Astrophysics sequence for physics majors starting in Fall 2017, and will look toward offering upper-level courses, with titles like Stars and Compact Objects, Galaxies and Cosmology, and Radiative Processes.
Battersby is keen to continue her outreach program, called BiteScis, pairing science graduate students with K-12 teachers to bring science lessons into the classroom. With funding from the Templeton Foundation, she will create a website of searchable open-access lesson plans for teachers by grade level.
“I want all students to know that science can be an option for them,” says Battersby.
Although not all students of astronomy become astrophysicists, they learn valuable skills for many career paths involving problem solving, creativity, and the ability to work with large amounts of data, says Whitaker.
But the draw for most students – and for her – is that astronomy is just plain fun.
“I love astronomy because you just need a good idea and some imagination,” she says. “In the words of Carl Sagan: Somewhere, something incredible is waiting to be known.”