Steve Zepf, professor and associate chair of astronomy. Photo by G.L. Kohuth.

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Steve Zepf’s work takes him to the far reaches of the universe. Zepf, a professor and associate chairperson of astronomy for the physics and astronomy department, works in light-years, studying stars and galaxies.

Zepf’s area of expertise is globular clusters, a collection of stars packed together, but recently he’s been focusing his attention on black holes.

“If you get enough stars together, you may think there should be a black hole there too,” Zepf said. “It turns out that all galaxies have black holes at their center.

“So it’s a question whether these globular clusters, these collections of stars, do too. And nobody’s ever been able to find one, and then we found one.”

Zepf’s current research has him in line to use the recently refitted Hubble Space Telescope. In a few months, the Hubble will target a globular cluster surrounding a black hole, looking to see how the black hole interacts with the dense collection of stars around it.

“We found all sorts of other gas and stuff emitting that’s falling out of the black hole, but … it could also shoot out big jets of material moving at really high speeds,” Zepf said. “So we see evidence of that, but we really want to know where it’s happening, and that’s what the Hubble data is for.”

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