No, it’s not a follow-up song to Lou Bega’s one-hit wonder “Mambo No. 5.” The light from the galaxy known as MAMBO-9 traveled for 13 billion years to reach us, making it the most distant star-forming galaxy ever observed with a telescope.
This monster galaxy is considered a giant stellar nursery and is full of dust, a required ingredient to form stars. The rate of star formation in a galaxy like this can reach a few thousand times the mass of our sun each year – compared to our own galaxy, which forms three solar masses in a year.
The surprising thing about this galaxy, imaged using the Atacama Large Millimeter/submillimeter Array in Chile, is its age. It formed 970 million years after the Big Bang, which means it began during the infancy of the universe.
Astronomers didn’t expect to find gigantic stellar nursery galaxies dating this far back, but the discovery of MAMBO-9 and other galaxies from the dawn of the universe are changing their understanding.
Given their massive amounts of star production so early on, galaxies like this could have influenced the universe and helped it evolve.
But the dust from these star factories, and their incredible distance from us, tends to obscure them from view.
A study including the findings from the telescope data published this week in the Astrophysical Journal.
“These galaxies tend to hide in plain sight,” said Caitlin Casey, study author at the University of Texas at Austin. “We know they are out there, but they are not easy to find because their starlight is hidden in clouds of dust.”
Ten years ago, study co-author Manuel Aravena at the Universidad Diego Portales in Chile first detected the light from the galaxy using the MAMBO instrument, or the Max-Planck Millimeter BOLometer on Spain’s IRAM 30-meter telescope – hence the name for the galaxy. But they weren’t able to gather enough information to understand the distance and age of the galaxy.
“We were in doubt if it was real, because we couldn’t find it with other telescopes. But if it was real, it had to be very far away,” said Aravena, who was a PhD student in Germany when he made the first detection.
The telescope array in Chile, known as ALMA, is sensitive enough to detect these distant, dusty galaxies. But the biggest impediment to finding such faraway galaxies are actually other galaxies, as those closer to us block out the more distant ones with their light. Sometimes they can offer an assist through gravitational lensing, which bends light from the more distant galaxies around them, making them easier to spot. However, this can distort the distant galaxies as well, making it harder to learn more about them.
But the researchers spotted MAMBO-9 without gravitational lensing, making it the most distant galaxy to be seen without this distorting effect.
“The total mass of gas and dust in the galaxy is enormous: 10 times more than all the stars in the Milky Way. This means that it has yet to build most of its stars,” Casey said.
In the image, a second component can be seen. The galaxy is actually merging with another one, hence the two parts.
The researchers are hopeful that data from ALMA will be able to help them find more distant and dusty galaxies to understand how many there are and why they formed early in the universe’s timeline.
The dust also presents a mystery they want to investigate further.
“Dust is normally a by-product of dying stars,” Casey said. “We expect 100 times more stars than dust. But MAMBO-9 has not produced that many stars yet, and we want to find out how dust can form so fast after the Big Bang.”