Webb Telescope finds shock wave wreaking havoc among 5 galaxies

Last year, when I covered the groundbreaking set of cosmic images from the James Webb Space Telescope, I described a phenomenal portrayal of Stephan’s Quintet with a bunch of contradictory words – which, I admit, tends to be common practice when talking about deep space shows.

This herd of five galaxies, some of which swirl far too close to be comfortable, harbors a realm “worthy of a fairy tale universe,” I said. But I also couldn’t help but feel bothered by the “terrifying” black hole lurking in the center of another shimmering mist and calling this corner of the universe a global “creepy” because these galaxies are surely locked in ultimately fatal air. – upsetting dance.

And the more we learn about Stephan’s Quintet of Dark Angels, the clearer it becomes that this part of our world is just as majestic and awe-inspiring as it looks. At an annual American Astronomical Society press conference on Monday, scientists said further observations with the JWST and the powerful Atacama Large Millimeter/submillimeter Array, or ALMA, have revealed absolute results. chaos is happening among these five luminous galaxies.

First, a galaxy – officially named NGC 731b, also known as the “intruder” – generates a giant shock wave, several times the size of our entire Milky Way, because it “encroaches” on the intergalactic space of the other four. Along the way, this extremely intense wave causes a lot of drama as it starts a “recycling factory” for hot and cold molecular hydrogen clouds among the quintet.

“A molecular cloud breaking through intergalactic gas and wreaking havoc in its wake may be rare and not yet fully understood,” Bjorn Emonts, astronomer at the National Radio Astronomy Observatory and co-investigator of the project, said in a press release. . . “But our data show that we have taken a new step in understanding the shocking behavior and turbulent life cycle of molecular gas clouds in Stephan’s quintet.”

And as if that weren’t wild enough, the team also located a huge gas puddle near the quintet, periodically breaking apart as a separate tail of hot gas forms nearby.

To summarize this last element, this tail is an indication of a possible baby galaxy. Yes, that would add another character to the tumultuous sit-com at this end of the universe which, thankfully, is between 39 million and 340 million light-years from where you’re sitting. (One of the galaxies, in the foreground, is significantly closer than its dancing partners).

The root of chaos

Shock waves, like the one that passes through the neighborhood of Stephan’s Quintet, are usually produced in front of an object traveling faster than the speed of sound, through some kind of gaseous medium.

In this case, NGC 731b is the object, tearing through the gaseous fabric of space at an astonishing speed of 800 kilometers per second (nearly 500 miles per second). “At this speed,” the statement said, “a trip from Earth to the Moon would take only eight minutes.”

“In 2006, our team, using Spitzer, discovered a remarkable fact,” said Philip Appleton, a Caltech astronomer and co-author of a study of the findings, at the conference.

In the shock wave, the researchers found a huge amount of certain hydrogen molecules radiating in the infrared, mixed with X-ray emissions usually thought to stay pure when they arise from such phenomena. “These molecules would not normally survive shock waves traveling faster than 30 to 50 kilometers per second,” Appleton explained.

So intuitively the team wondered, what’s going on here?

Which brings us back to the major disarray I was talking about earlier.

Basically, the team realized that the gaseous medium that this shock wave was plunging into was a bit “lumpy”. And those clumps, Appleton explained, appear to break up into smaller clumps, called clouds, as the shock travels through space — and those clouds are the source of the questionable hydrogen emission. Then, Appleton said, all that hydrogen joins the violent shock wave itself.

In other words, the hydrogen in the region appears to be “recycled” through the hot and cold gases surrounding the shock wave. And in 2006, the team detected all that recycled hydrogen while tracking the wave.

“It’s important because molecular hydrogen forms the raw material that could ultimately form stars,” Appleton said in the release, “so understanding its fate will tell us more about the evolution of Stephan’s Quintet and galaxies. in general.”

Moreover, as the shock wave passes through its clumped obstacles, all of this violent activity creates what Appleton calls “unexpected structures” due to the whole recycling situation. One of these strange structures is essentially two cold clouds connected by a thread of hot molecular hydrogen. Think of a high-speed bullet piercing a cloud and forming a ring-shaped silhouette in its wake.

And the other, of course, is what appears to be the tail end of a budding galaxy.

“What we’re seeing is a giant cloud of cold molecules disintegrating into a super hot gas, and oddly enough…it just goes through hot and cold phases,” Appleton said. “We don’t fully understand these cycles yet, but we do know that the gas is recycled because the length of the tail is longer than the time it takes for the clouds it is made of to be destroyed.”

In the future, the team intends to use spectroscopic observations to trace exactly how all the gas around the shock wave is moving. In this way, it would be possible to determine how fast the gas is moving and How? ‘Or’ What it heats up or cools down as the shock wave passes through the area.

That leaves us at a famous pit stop – the one through which most of the greatest astronomical discoveries of our generation tend to pass.

“These new observations gave us some answers, but ultimately showed us how much we don’t know yet,” Appleton said. “Essentially, we have one side of the story. Now is the time to have the other.”