NASA’s Hubble Space Telescope captured rare images of the brightest galaxies in the universe — galaxies that may contain vital clues on how stars and galaxies form, researchers announced this month.
These galaxies are very rare, only a few dozen exist in the universe, and each one blazes with infrared light that is between 10 trillion and 100 trillion times more intense than the sun, said James Lowenthal, lead researcher and professor of astronomy at Smith College.
Hubble’s lenses were able to photograph the galaxies by taking advantage of a phenomenon called gravitational lensing. It occurs when the gravity of a massive galaxy or a cluster of galaxies magnifies the light of a more distant, background sources, said Lowenthal.
“We have hit the jackpot. . . . Lensing magnifies [the galaxies] so that you can see small details that otherwise are unimaginable. We want to understand what’s powering these monsters, and gravitational lensing allows us to study them in greater detail,” said Lowenthal.
The galaxies are also veritable star-factories, pumping out more than 10,000 new stars every year, according to Lowenthal. This has led researchers to think that studying the galaxies may reveal clues about how galaxies formed billions of years ago.
“There are so many unknowns about star and galaxy formation. We need to understand the extreme cases, such as these galaxies, as well as the average cases, like our Milky Way, in order to have a complete story about how galaxy and star formation happen,” Lowenthal said.
The question of why these galaxies in particular are producing so many stars is one that has eluded researchers, but Lowethal is hopeful that this recent discovery will spur others.
“They’re hard to study because the dust makes them practically impossible to study in visible light. They’re also very rare: They don’t appear in any of Hubble’s deep-field surveys. They are in random parts of the sky that nobody’s looked at before in detail. That’s why finding that they are gravitationally lensed is so important,” he said.
The researchers hope to use the Gemini Observatory in Hawaii and NASA’s James Webb Space Telescope — Hubble’s successor set to launch in October 2018 — to study the galaxies in more detail.
“The sky is covered with all kinds of galaxies, including those that shine in far-infrared light,” Lowenthal said. “What we’re seeing here is the tip of the iceberg: the very brightest of all.”