Hidden galaxy found far, far away

Astrophysics professor Judith Irwin makes six billion year-old scientific breakthrough through radio imaging

The unnamed galaxy was discovered nearly seven billion years behind UGC 10288.
The unnamed galaxy was discovered nearly seven billion years behind UGC 10288.
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Queen’s professor Judith Irwin has discovered a new galaxy, which will help astronomers shed light on the nature of the mysterious celestial bodies.

The discovery, which was made in a study conducted by 28 astronomers from across North America and Europe, could help scientists better understand the physical make-up of galaxies.

The new galaxy, which is over six billion light years away from Earth, was found after researchers studied radio emissions from 35 different galaxies.

The galaxy, which has yet to be named, appears as a vertical jet coming from the spiral galaxy UGC 10288, Irwin said, but on closer examination it turned out to be a galaxy much farther away than the first one.

“The foreground galaxy is 100 million light years away.

“The background galaxy is more than six billion light years away,” Irwin said.

“That clinches it, that it’s really a background source.” The team, which represents seven countries, comes from an international consortium of researchers.

The consortium pools their resources to study aspects of 35 galaxies.

A paper documenting their findings has been published in The Astronomical Journal, which publishes original research for the wider scientific community.

Irwin looked up the location of the new galaxy, she said, and found that something called redshift had been observed in its light emissions, indicating its distance from the Earth.

Redshift describes a phenomenon where the wavelengths of emissions increase as faraway objects become more distant.

The newly discovered galaxy could be an elliptical galaxy, Irwin said.

Elliptical galaxies are flat or spherical, unlike a spiral galaxy such as the Milky Way.

“We can’t tell what it is,” Irwin said.

“However, these big jets, they tend to come from elliptical galaxies, not spirals.” Irwin said the distance of the galaxy allows us to look into the past.

“It’s not what it looks like now but what it looked like six billion years ago, because it’s taken that long for the light to come [to Earth],” she said.

In comparison, scientists estimate the age of the Earth at 4.54 billion years old.

Many elliptical galaxies have jets coming out of a region surrounding its centre, she noted, which is often a supermassive black hole.

Jan English, a professor at the University of Manitoba and former Queen’s graduate student, also took a prominent role in the project and helped publicize the discovery, according to Irwin.

The team used data from the Very Large Array (VLA), a series of radio antennae in New Mexico, which allows astronomers to observe high levels of detail using radio emissions.

What humans see in the night sky, Irwin said, is a tiny fraction of the actual activity in the universe.

“You’re looking at what you might call the vacuum of space, but it’s not really a vacuum,” she said. “There are high energy particles. If you look in other wavelengths you can find them.”

Radio waves have much larger wavelengths than visible light, she said, which means a larger telescope is required to get the same level of detail.

The VLA solves this problem, she said, by using a group of antennae to act as one telescope.

Each antenna captures images of faraway objects as the Earth rotates to view them.

Irwin added that the discovery of the new galaxy helps the team with their original goal, which was to investigate radio halos around galaxies.

The new galaxy lets the astronomers see how radio emissions from the new galaxy are “polarized”, or filtered, by the galaxy in front of it.

Light from UGC 10288 is filtered by the galaxy in front of it, she said, similar to how a pair of sunglasses filters sunlight.

“We can measure that change,” she said.

“It tells us the actual strength of the magnetic field in the halo of the foreground galaxy without actually seeing it.”

The study, she said, leads the way for other researchers to learn more about distant celestial bodies.

“It’s important aesthetically because you really do see a three-dimensional universe … our sensitivity is now so good you’re seeing galaxy upon galaxy.”

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