Today, we have just one science story, and it has one terribly large hole poked through the center of it; a literal hole scientists are having fun explaining. This artist’s rendition shows you what appears to be a messy ring of star formation with nothing in the center. The actual tiny blob of light observed with Hubble and Keck lacked the pixels to make this appear pretty and only shows what is happening in a single filter. Named R5519, this object is located 11 billion light-years away, and we’re seeing how it appeared just a few billion years after the Big Bang. As keeps coming up in a case of science on repeat, no one expected there to be a lot of fully formed, major spiral galaxies already existing at that point in the universe’s history, but here we are, again, looking at something that can only be explained by rapid galaxy formation.
The global team studying this object, which was led by Tiantian Yuan, believes they’ve found the carnage of a galaxy collision, where one system punched a hole through the disk of another system. These kinds of collisions are exceedingly rare but have been seen before in the current universe, where galaxies are often found in groups and clusters, and there are more fully formed galaxies than we believed existed in the early universe. Despite all the news in the past week about fully formed galaxies being found by 2 billion years after the Big Bang, we’re still going to stick with – there were fewer then, and galaxies were still actively forming.
Despite the spread-out nature of these early galaxies, and their smaller numbers, R5519 makes it clear that when a galaxy really wants to punch something, it will find a way, and some galaxy definitely found a way to punch all the way through R5519. This event left a dark empty void in this Milky Way galaxy-sized system, and triggered massive amounts of star formation; the ring that the team sees is undergoing 50 times the rate of star formation of our own galaxy!
This work is published today in the journal Nature Astronomy. In this paper, they go on to argue that this discovery may imply that these kinds of collisions may have been more common in the early universe. As personal commentary, I’d like to say, I’m not sure we can say that yet. What this discovery tells us is there is a ring galaxy where they happened to be looking, and given all the remarkable things that we have reported on in the past few weeks, I think it’s time to reset our expectations of what was happening in the first few billion years of the universe because clearly, no one was expecting this or any of the other remarkable stories of massive galaxies that have been coming out in the past 3 weeks.
Astronomers see ‘cosmic ring of fire’, 11 billion years ago
“A Giant Galaxy in the Young Universe with a Massive Ring,” Tiantian Yuan et al., 2020 May 25, Nature Astronomy (Preprint)