The smallest "supermassive" black hole ever recorded has been discovered at the heart of a distant galaxy by scientists who were led on a multitrillion-mile trek through the cosmos by a former Northport resident.
Vivienne Baldassare, a doctoral student in astrophysics at the University of Michigan and a 2008 graduate of Northport High School, set her sights on a galaxy 340 million light years from Earth, where she and her collaborators found the black hole. They are calling it an "oxymoronic" black hole because not only is it the smallest, it is also a supermassive, Baldassare said.
"One thing that's interesting about this one is that it is in the center of a dwarf disc galaxy," she said, and is only a fraction of the Milky Way's size. A disc galaxy means the system as seen from afar looks round, like a disc.
"The galaxy is roughly two-and-a-half billion times the mass of our sun," Baldassare said.
Galaxies are systems consisting of millions -- or in the case of the Milky Way, billions -- of stars. Gases also pervade galaxies, she said, and so does dust. Galactic systems, regardless of size, are held together by gravitational forces, Baldassare said.
She and her team estimate the black hole is about 50,000 times the mass of our sun. This is less than half the mass of the previous smallest black hole found at the center of a galaxy, Baldassare said.
The oxymoronic black hole, she said, may provide clues on how larger ones formed in their host galaxies billions of years ago. A black hole exists at the center of the Milky Way.
Black holes have a reputation in urban legends as vast, dark and invisible vortices sucking up everything near and far, including stars.
Nothing could be further from the truth, said Baldassare, 24, who reported her team's findings in the current issue of The Astrophysical Journal Letters.
"A black hole is an object that's so dense that not even light can escape from its gravitational pull," Baldassare said. "If we were to take away the sun and replace it with a black hole the same size of the sun, the gravitational pull on the Earth would be the same."
"We would not get pulled into it," said Baldassare who graduated from Hunter College's Macaulay Honors College before enrolling at the University of Michigan in Ann Arbor. She will finish her doctoral program in 2017.
She and her team of astronomers used NASA's Chandra X-ray Observatory and the 6.5-meter Clay Telescope in Chile to find the oxymoronic black hole in a galaxy dubbed RGG 118.
Megan Watzke of the Chandra X-ray Center in Cambridge, Massachusetts, said while the Clay telescope is land-based, the Chandra has a view from on high.
"It's in space," said Watzke, noting that the Chandra X-ray Center is part of the Harvard-Smithsonian Center for Astrophysics. The Harvard-Smithsonian Center operates the space observatory under contract with NASA.
Baldassare said there is much to be learned from her team's data.
"We are interested in determining if dwarf galaxies and their black holes behave the same way as black holes in large galaxies," she said.
"The Chandra X-ray Observatory orbits around earth and looks at X-rays. It examines material that is hot," Watzke said.
"Black holes are very strong points of gravity, so not all material falls in," Watzke said, adding that some of it circles the hole as if circling a drain. The material is searingly hot and emits X-rays, which Baldassare and her team studied.
CORRECTION: The galaxy is 340 million light years away and is two-and-a-half billion times the Sun's mass. It also is not the most massive black hole. An earlier version of this story was incorrect.