What are cannibal galaxies and how do they grow in space?

In space, the distances are enormous and often we cannot measure them on a human scale when we talk about planets, suns and galaxies. In the life of galaxies, the interaction with neighboring galaxies plays an essential role. So much so that, despite the space that separates them, they end up hatching there devouring each other.

It is that the galaxies do not exist individually. Most form multiple systems in which they live and evolve under the influence of other nearby galaxies. Observing them interacting millions of light-years away also allows us to know the behavior of our galaxy, the Milky Way, in its evolution over time.

This week a galaxy was discovered that mirrors the very first version of our home galaxy, the Milky Way. The galaxy, nicknamed The Magic Sparkler is embedded in a system of ancient star clusters and eagerly feeds on its smaller galactic companions to grow, according to a recent study published in the Monthly Notices of the Royal Astronomical Society based on observations of the mighty james webb space telescope (JWST).

Sparkler’s discovery, named after its two dozen orbiting globular clusters, offers unique insight into the early formation history of the Milky Way. Globular clusters are dense collections of about one million stars. The Milky Way is currently home to about 200 globular clusters..

“The population of galaxies in the universe is changing in ways we couldn’t even imagine a few decades ago. It’s something that happens on such a different scale than humans, both in size and time, that it seems impossible. But galaxies collide. They crash all the time. As a result of these collisions, the galaxies deform and, going to the essentials, they merge. This is how they grow and, in the long run, the bigger ones end up integrating the smaller ones. It’s a metaphorical cannibalismof course, there’s nothing strange about that, it’s a completely understandable and reasonable physical process that happens,” he explained to GlobeLiveMedia William Abramson Doctor in physics and astronomer.

“Galaxies collide all the time because the distance between them (although it is huge) is not much greater than the size of the galaxies themselves. Instead, the distance between the stars that make up each galaxy is huge compared to the size of the stars, so when the galaxies (which are collections of stars) collide, they pass through each other like ghosts. The stars don’t collide. But their trajectories change. When a small galaxy approaches a large one (it falls on it, we can say), the tides that occur stretch it, and star tails are formed (tides, because it’s the same phenomenon than the tides of the Moon on Earth, on a much larger scale),” added Abramson, who is a professor at the Balseiro Institute.

And he added: “Then the small galaxy makes several passes over or through the large one (depending on the direction of the impact). With each pass, several of its stars leave the small galaxy and begin to orbit around the center of the large galaxy. Finally, only the very stretched tidal tail remains, and perhaps the core, which, due to its tighter stars, can survive. Astronomers detect these structures in large galaxies and can piece together the history of how these collisions in the past built up the large galaxy.

The Sparkler galaxy lies in the constellation Volans in the southern sky. The team, led by Professor swinburne university, Duncan Forbes, and the professor of San Jose State University, Aaron Romanowsky, examined the age of Sparkler and its surroundings by examining the abundance of elements heavier than hydrogen and helium. Astronomers call these heavy elements “metals”.

This galaxy and its globular cluster system were detected with a redshift of 1.38, implying that we see the galaxy a few years ago. 9 billion years. The observations are made possible by the new JWST and the lens flare effect of a gravitational lens, which is randomly aligned in front of the galaxy.

Looking at the compact star clusters that surround the galaxy, they realized they looked like younger versions of the clusters around the Milky Way. Many are rich in metals, similar to the globular clusters in the central bulge of our galaxy. The researchers also observed mid-age, metal-poor clusters that are associated with a satellite galaxy that Sparkler is devouring, with its globular clusters acting as a desert.

Abramson explained that astronomers call all elements heavier than the metals hydrogen and helium, which make up the overwhelming majority of all matter in the entire universe. “Some are easier to observe with different types of telescopes, and serve as indicators: carbon, oxygen, nitrogen, sulfur, among the lightest, but also silica, iron, etc. These are the chemical elements that we know, those of the periodic table. They are the same throughout the universe. The chemical composition of galaxies evolves as stars convert light elements into heavy elements in their cores, and when they “die”, they deliver them to the interstellar medium to form successive generations of stars. In this sense, a population of stars is said to be ‘young’ or ‘mature’,” the researcher also said. Conicet.

The Sparkler galaxy is currently only 3% the mass of our galaxy, but researchers expect it to grow through this feeding process on cosmic timescales to eventually equal to the mass of the Milky Way as we see it today. “We seem to be witnessing firsthand the assembly of this galaxy as it accumulates its mass, in the form of a dwarf galaxy and several globular clusters. We are excited about this unique opportunity to study both the formation of globular clusters and a fledgling Milky Way, at a time when the Universe was only a third of its current age,” Forbes said in a statement. communicated.

The observations are made possible by the impressive infrared observing power of the JWST and a phenomenon first predicted by Albert Einstein in 1915 in his theory of general relativity where the great physicist suggests that objects of great mass “deform” the fabric of space like a heavy ball resting on a stretched sheet of rubber. As with this simple analogy, the larger the mass, the more extreme the curve it causes.

This means that extremely massive objects like black holes waves galaxies they can “bump” space enough to distort light as it passes through them. Therefore, if the light from an object in the background experiences this distortion, its travel time is affected. This can lead to this background object being amplified by this foreground landing object, which is described as a “gravitational lens”. The Sparkler galaxy is illuminated by such a gravitational lens that allows JWST to detect its light that has been traveling for 9 billion years to reach the powerful space telescope.

“The collision of two galaxies is for me one of the most extraordinary events in the universe. To begin with, energetically, it is something enormous. And, when they intersect as I have already said, though the stars do not collide, the gas that fills the space between them (which is very weak but not empty), it smells of shock. It is compressed a lot and an episode of training many new stars is unleashed, “said Abramson, author of the blog En el cielo las estrellas.

And he concluded: “In photos of galaxy collisions, we see these new stars glow fiercely in blue colors, while their radiation causes interstellar gas to glow in pink colors. That is, as a result of the collision, new stars are formed, almost all of them with their planets around them, some perhaps with living beings, who can tell you. It is a mechanism that converts the kinetic energy of galaxies into “people”. It’s extraordinary”.