Astronomers have discovered a swarm of galaxies orbiting a distant, ultra-bright galaxy that is forming stars at an intense rate, showing that early galaxies grew in dense environments.
Interactions with these satellites galaxies The central galaxy – called W0410-0913 – can feed gas and stars, helping it grow to 10 times its size. Milky Way. However, the researchers found that these galaxies do not cause as much chaos at W0410-0913 as scientists previously thought.
The results could reveal clues about how bright galaxies can become and how they might have quasi-stellar radio sources, or quasarsin active galactic cores fueled by starvation supermassive black holes.
These massive cosmic monsters feed on gas, dust, and even starsThey emit an enormous amount of light, often becoming brighter than every combined star in their host galaxy.
W0410-0913 is one of the brightest, most massive and gas-rich galaxies. Because it takes a long time for the light to travel from the galaxy to a land, we see it 12 billion years ago when the universe was less than 2 billion years old. They are part of a class of galaxies called “dust-shielded hot galaxies” or “hot dogs” for short.
These galaxies are so named because the large clouds of dust within them are heated by starlight and energy from the center Black holecausing the gas to glow and emit infrared light.
“Before they evolve into a full-fledged quasar, some galaxies are thought to go through a phase of very dusty and ‘active’ in terms of star formation and gas accumulation on central supermassive black holes,” team leader and ESO astronomer Michel Ginolfi said in a statement. statement (Opens in a new tab). “We set out to design an experiment to learn more about this transition.”
Not only did Ginolfi and colleagues want to study W0410-0913 in isolation. Looking at how the galaxy’s surroundings affect its evolution, the team set out to study a region of W0410-0913 that was 40 times as wide as the galaxy itself, using VLT’s Multi Unit Spectroscopic Explorer instrument.
“Observations have revealed that W0410-0913 is surrounded by a swarm of at least 24 smaller galaxies,” Peter Laursen, a researcher at the Cosmic Dawn Center in Denmark, said in the statement. These galaxies may help feed gas and stellar material to W0410-0913.
The team’s research revealed that W0410-0913 is located in a region of space that is at least 10 times the density of an average region in the universe. This finding supports previous research showing that hot dogs exist in dense cosmic environments.
Although seen as it was when the universe was less than an eighth of its current age, W0410-0913 has actually grown larger than our galaxy, Milky Way.
For a galaxy to grow to such a massive size so quickly while also feeding a supermassive black hole, it must have a steady supply of new material. Current thinking suggests that this matter is provided by the growing galaxy as it draws in gas, and even smaller satellite galaxies, with its enormous energy. gravity.
The ultra-dense environments of hot DOG galaxies, which should raise the rate of galactic interactions, will also help with this feeding.
The history of violent interactions with other galaxies suggests that W0410-0913 must be a chaotic spectacle of gas clusters and runaway stars. But the data ALMA collected regarding the gas movement in this hot dog appears to paint a different picture.
Instead, the team found that W0410-0913 did not appear to be disturbed by interactions with companion galaxies much at all. Instead, the galaxy’s gas orbits in an orderly fashion around the central black hole, albeit at very high speeds – up to a million miles per hour (1.6 million km/h).
“However, despite the expected frequent mergers with other galaxies, these gravitational interactions are not necessarily destructive – they feed the central galaxy and spin the gas a little, but leave it practically intact,” Ginolfi said in the statement. “It’s a bit like throwing small pebbles at a plate of hard glass: you can scratch it, but you won’t break it.”
The team’s observations shed light on the processes behind the evolution of this rare and extreme group of hot, dust-obscured galaxies, suggesting that the interactions that form them may not always be as chaotic as previously thought.
“When we pair the results from two very different telescopes, we see a picture of how the most massive and dusty galaxies evolve,” Ginolfi said. “This type of galaxy, which is a vital stage in the transition from a dusty and star-forming galaxy to a quasar, tends to grow in very dense environments.”
The team’s research was published August 5 in the journal Nature Communications. (Opens in a new tab)