A serendipitous discovery has given astronomers the first glimpse of a monstrous galaxy from the early universe. We've long lacked evidence for the existence of this type of galaxy, but now, thanks to the ALMA observatory, we've found a mysterious trace. For this reason, the team likens their discovery to finding a yeti footprint.
Now that the cryptid analogies are out of the way, let’s focus on what the data is telling the researchers. The source appears to be visible in a very specific infrared light range, which allowed astronomers to gauge some of the properties of the galaxy. The discovery is reported in The Astrophysical Journal.
Since it is invisible in other wavelengths, the galaxy is shrouded in a thick cloud of dust. It is believed to be a pretty massive galaxy since it has as many stars as the Milky Way has today. This is quite striking. The light from the galaxy comes from a time when the universe was only a billion years old, and its size is truly impressive. And it’s growing really fast too, producing stars 100 times faster than our own galaxy.
"It was very mysterious because the light seemed not to be linked to any known galaxy at all," lead author Dr Christina Williams, from the University of Arizona, said in a statement. "When I saw this galaxy was invisible at any other wavelength, I got really excited because it meant that it was probably really far away and hidden by clouds of dust."
The galaxy could also be an important piece of the puzzle in terms of explaining early galaxy evolution. Astronomers have discovered many early massive galaxies that must have grown extremely quickly, but so far their likely ancestors appear to have grown slowly, which doesn't quite make sense. Objects such as this might be the real progenitors.
"Our hidden monster galaxy has precisely the right ingredients to be that missing link because they are probably a lot more common," Williams explained.
The observations conducted by ALMA only focused on a minuscule part of the sky, about 1 percent of the apparent area of the full Moon. The researchers might have been lucky or these kinds of galaxies might be common. Observations from the upcoming James Webb Space Telescope, which is set to launch in 2021, may well find a lot more of these “mythological” galaxies.