Galaxy quest


Data from Subaru telescope, and later analyzed further by the Keck Observatory, has provided insight on two galaxies far in the universe’s past.

Even more interesting, Subaru spokeswoman Suzanne Frayser said, is that the lead author on the paper, Yuya Nakahiro, was only a college senior when he completed the analysis.

“Usually the senior person would be the first author on the paper,” Frayser said. “In this case, they put (Nakahiro) first.”

Scientists using Subaru observed an odd-shaped galaxy. The Japanese scientists who saw it likened it to a magatama, a stone amulet. American scientists, observing it later, also described it as comma-shaped. Further research showed the object was actually two galaxies, with the background one being about 11.6 billion light-years from Earth, and the foreground one being closer to 9.9 billion light-years from Earth.

That, too, was an unexpected find, so much so that astronomers initially discounted the idea that the object was actually two galaxies, Frayser said.

“It was so unusual you would have two objects in that line of sight,” she said.

But once scientists confirmed the one object was two, it opened up several new possibilities for study.

“If there are two, we can measure the impact of gravitational lensing,” Frayser said.

Those duties fell, in large part, to Nakahiro, who wrote his senior project on the galaxies.

“He was looking at the degree to which the foreground galaxy was affecting what you see of the background galaxy,” she said, adding the impact turned out to be relatively small, because the closer galaxy was still forming.

Gravitational lensing refers to the process in which light from a background object bends around a closer object. In the process of bending around the closer object, the light from the background is amplified, appearing brighter and illuminating the background object more clearly for study.

To better understand the information provided through gravitational lensing, scientists need to know how large the gravitational amplification is. That’s where Nakahiro came in, performing most of the amplification research.

Frayser said Nakahiro, who completed his work in Japan, was excited to be named the lead researcher in the paper, published in the April edition of Astrophysical Journal.

“I didn’t imagine that I could publish the results of my research in a revered astronomy journal,” Nakahiro said in a prepared statement.