Our Milky Way galaxy lives in a small group of others, including the Andromeda galaxy and a few dozen much smaller ones. But there are larger groups: galaxy clusters can have hundreds of large galaxies orbiting their mutual center of mass.
We believe that these clumps were one of the earliest and largest self-gravitational structures to form in the universe, as ordinary matter — electrons, protons, and so on, of which we are made — fell and merged around huge threads. dark matter shortly after the Big Bang. Some of these huge clouds of gas began to break down, and at the same time they disintegrated, creating flocks of protogalaxies that revolved around each other. If one protogalaxy grew a little larger than the others, it would attract more material and grow much faster, forming many stars in the beginning, even if the other protogalaxies were still coming together.
Thus a protoscope is formed, and because the protogalaxies in it self-organize by gravity, they eventually become true galaxies, and the protocluster becomes a true cluster.
Astronomers have found quite a few protoclusters by looking deep into the universe – the ultimate speed of light means we see objects that are very far away, as in childhood. Look back far enough and you will be able to see things as they existed when the universe was young and the protoclusters were ordinary.
Galaxies that create many stars are very bright in ultraviolet light, so to look for protoscopes, you can look for clusters of such bright UV galaxies. This is a tried and true method.
But what if the galaxies in the protoscope die young? So young that not very bright in UV. Until recently, most astronomers thought this had not happened, so why worry about it?
The inside of a massive cluster of Coma galaxies where thousands of galaxies are swarming. Author: NASA, ESA, J. Mack (STScI) and J. Madrid (National Organization of the Australian Telescope)
Photo: NASA, ESA, J. Mack (STScI) and J. Madrid (Australian Telescope National Facility)
Yeah. Yes, that is, the opening of the protocol called MAGAZ3NE J095924 + 022537 – let’s call it short J0959 [link to paper]. It was not found by searching for clusters of galaxies, bright ultraviolet radiation, but instead it was spotted in a survey of the deep universe called UltraVISTA, a super-deep study using the 4-meter VISTA telescope. A team of astronomers found a pair of galaxies next to each other in the sky and about the same distance from Earth; their light took a staggering 11.8 billion years to reach us, so we see them when the universe was only 2 billion years old.
The following observations were made using a camera on the Keck telescope for a project called Massive Ancient Galaxies At z> 3 NEAR-Infrared, or MAGAZ3NE – z is a label that astronomers use for redshift, which itself shows us the distance to galaxies; redshift z> 3 is really very far. They found that the two galaxies were at the centers of two different but neighboring protoscopes separated by about 100 million light-years. But they are very different.
J0959 has one really large galaxy with a mass of over 200 billion suns, which is impressive for such an early space time. They also discovered 38 other protogalaxies that are forming around it, but they are … amazing. For the most part, 73% of galaxies don’t seem to form stars! Usually this share is over 11% for the protoclusters at that time in the universe, so something really strange is happening in this protocluster.
If a galaxy can’t create stars, eventually all the stars in it die, and the galaxy metaphorically dies too.
What kills all these galaxies?
Cluster of Virgos and more. Credit: Rachel Bernal Andrea
Photo: Rogelio Bernal Andreo
Astronomers call this suppression of star formation extinguishing. We see it to a lesser extent in the neighboring universe in fully formed clusters, such as the Virgo cluster, where a handful of galaxies seem to die, and in some clusters where it is wider, such as the Coma cluster, where many galaxies of citizens seem to be extinguished. This is usually due to the environment of the cluster: all galaxies move through the cluster, and there is a small amount of gas between the galaxies through which they move. If they break through this material, it can blow out the internal gas of galaxies, which is used to create stars. When they lose this gas, they lose the ability to create stars and go out.
But in protoclusters such suppression is rare; galaxies have huge amounts of gas in them as they form, and must fruitfully create stars. This is something that has been seen everywhere in the past.
The galaxy cluster MACS J0416.1-2403 is about 4 billion light-years from Earth, but its gravity increases even more distant galaxies behind it, allowing astronomers to explore a very early universe. Author: NASA, ESA and HST Frontier Fields (STScI)
But not in protocol J0959. However, astronomers have noticed something else: the more massive the galaxy in the protoscope, the more likely it is to fade. This means that not only the external environment, but also something that happens inside the galaxy, stops the birth of stars.
The question is. And this is unclear. It should be noted that the other protocol cluster found next to it looks normal in all other respects, so this is something unique for the J0959 protocol cluster.
Well, so far unique. This is the first ever found similar. This is partly due to the different way it is found; the old way of finding clusters of galaxies with ultraviolet bright mostly gives “normal” protoscopes and prevents the search for redeemed, so otherwise you can find more of them.
That would be interesting! Finding a protoscope with extinct galaxies in it shocks how to find a newborn baby is a member of the AARP. The timeline doesn’t make sense, so something really special is happening. Not so long ago protoclusters were theoretical, and the first ones were discovered only recently. And in general in science, when you discover a new object, it’s usually because it’s easiest to find: the brightest, usually in astronomy, or the closest. So it is natural that we will first find the ultraviolet and then start finding the outstanding ones.
But is the J0959 protoscope outstanding, or are such structures with a high proportion of extinct galaxies more often than we think? Now that we know they’re there, astronomers will be looking for more, and hopefully there will be new clues as to why they even exist.