Showing posts with label galexy. Show all posts
Showing posts with label galexy. Show all posts

Saturday 18 March 2023


Space Goth Grand Slam

In an effort to understand the origin of our galaxies, astronomers have spotted an insane, galactic showdown for the ages: four giant black holes in dwarf galaxies destined to collide, though not all in the same place. But boy, did they score a grand slam of astronomy firsts.

Using NASA's Chandra X-ray Observatory, the astronomers kept a close eye on two separate pairs of merging dwarf galaxies. One is in a cluster 760 million light-years away, the other, over 3.2 billion. Unfortunately, us humans are relegated to the nosebleeds for this one.

Still, we don't need to be close up to understand the significance of the findings, which were published as a study in The Astrophysical Journals. According to the researchers, it's the first evidence of large black holes in merging dwarf galaxies at all.

"Astronomers have found many examples of black holes on collision courses in large galaxies that are relatively close by," explained Marko Mićić, lead author of the study and an astrophysicists from the University of Alabama, in a press release."But searches for them in dwarf galaxies are much more challenging and until now had failed," he added.

Dwarfing Achievements

It's the dwarf galaxy angle that really makes this discovery significant. While they may not be as stunning in scope, dwarf galaxies are indispensable to understanding the evolution of galaxies as a whole.

The theories vary, but cosmologists generally believe that the initial dwarf galaxies, which formed hundreds of millions of years after the Big Bang, merged over time to form the large ones like our own that we're so familiar with.

"Most of the dwarf galaxies and black holes in the early universe are likely to have grown much larger by now, thanks to repeated mergers," said co-author Brenna Wells, an undergraduate researcher at UA, in the release.

"In some ways, dwarf galaxies are our galactic ancestors, which have evolved over billions of years to produce large galaxies like our own Milky Way."

All that goes to show why it's so frustrating that dwarf galaxies prove difficult to detect due to their lack of luminosity, and the fact they need to be observed at colossal distances.

Now that they've discovered not one, but four unique examples of them, the astronomers can return for followup observations — perhaps one of the best opportunities yet to understand the primeval galaxies of our universe.

Saturday 21 September 2019

The entire Galaxies are dying, Astrophysicists warn the scientific society!

Stripped of their ability to produce new stars, the unfortunate galaxies are stuck in time, slowly vanishing as their existing stars fade away or die in violent supernovas.

Now a team is investigating the nearby Virgo Cluster to figure out what’s going on in hopes that similar phenomena are happening there, project leader and McMaster University astrophysicist Toby Brown writes in The Conversation. Brown suggests that galaxies are being killed as they interact with the extreme conditions of tightly-packed galaxy clusters — but he’s not sure why.

Narrowing Down

To clarify, when Brown writes that “in the most extreme regions of the universe, galaxies are being killed,” he doesn’t mean that they’re suddenly vanishing. Rather, the formation of new stars within them is being shut down by yet-undetermined factors.

So far, Brown’s team has arrived at two possibilities, and Brown hopes that using advanced telescopes to probe the still-forming Virgo Cluster will tilt the scales one way or another.

Cosmic Starvation

The first possibility is called ram pressure stripping, a process through which all of the gas that a galaxy would use to form stars is vacuumed away by nearby intergalactic plasma. The other is that the environment inside a galactic cluster simply becomes too hot for cosmic gases to cool and condense into stars, rendering it useless as fuel.

“When you remove the fuel for star formation, you effectively kill the galaxy,” Brown writes, “turning it into a dead object in which no new stars are formed.”

READ MORE: Something is killing galaxies, and scientists are on the case [The Conversation]