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This image shows a rare view of four quasars, indicated by white arrows, found together by astronomers using the Keck Observatory in Hawaii. The bright galactic nuclei are embedded in a giant nebula of cool, dense gas visible in the image as a blue haze. Hennawi & Arrigoni-Battaia, MPIA
The odds of success would make a Vegas bookie sit up and take notice. But in a one-in-10 million chance, astronomers surveying the sky have found a group of four tightly packed quasars in one of the most distant parts of the universe. The rare grouping may be a nascent galaxy cluster, and its unusually cold cradle of gas could prompt a re-think of how we model the early universe.
Quasars are among the brightest objects known—according to NASA, each one gives off more energy than 100 mature galaxies combined. But quasars are found only in the far reaches of the universe and can't be seen with the naked eye. Because of the time it takes light to travel that far, detecting such distant objects is akin to seeing back in time, so astronomers think quasars are the seeds of young galaxies, powered by gases falling into the supermassive black holes at their cores. As matter falls inward and gets close to the speed of light, it emits radiation that we can pick up with telescopes.
The quasar phase doesn't last long, only about a thousandth of a galaxy's lifetime. After that, the brightness dies down as the inflow of matter slows, says study leader Joseph Hennawi, an astrophysicist at the Max Planck Institute in Germany. Seeing any two quasars close together while they are still bright is a chancy business, so his team wasn't sure what they'd find when they set out to survey quasars using the W.M. Keck Observatory in Hawaii. To their surprise, they quickly pinpointed four of them in close proximity, cosmically speaking. The quartet is huddled up in an area of sky less than 600,000 light-years across that sits about 10 billion light-years from Earth.
"The authors found it by investigating the environment of just 29 bright quasars," says Michele Trenti, a senior lecturer at the University of Melbourne's School of Physics. "So at face value it seems like winning the lottery with a handful of tickets." That's not all that was strange about this quasar quartet. The foursome was found inside a cloud of cold, dark gas, and the team's observations suggest that similar clouds surround about 10 percent of the tens of thousands of known quasars. That's odd, because according to current theories, quasars in groups like this should be surrounded by hot plasma, or ionized gas, at a temperature of about 10 million degrees.
“What this means is that there is some physical process that the models aren’t capturing,” says Hennawi, whose team reports the discovery this week in Science.
May 9, 2015 / Greg Giles / Comments Off on Astronomers Giddy Over What They Call A Cosmic ‘Dinosaur Egg’ About To Hatch
The Antennae galaxies, shown in visible light in a Hubble image (upper image), were studied with ALMA, revealing extensive clouds of molecular gas (center right image). One cloud (bottom image) is incredibly dense and massive, yet apparently star free, suggesting it is the first example of a prenatal globular cluster ever identified.
Excerpt from huffingtonpost.com A dense cloud of gas 50 million light-years away has astronomers buzzing, and they're using all sorts of strange metaphors to get the rest of us to pay attention.
They've discovered what they think may be a globular cluster -- a big ball of up to one million stars -- on the verge of being born.
“This remarkable object looks like it was plucked straight out of the very early universe," Dr. Kelsey Johnson, an astronomer at the University of Virginia in Charlottesville and lead author on a paper about the research, said in a written statement. "To discover something that has all the characteristics of a globular cluster, yet has not begun making stars, is like finding a dinosaur egg that’s about to hatch.”
ALMA image of dense cores of molecular gas in the Antennae galaxies. The round yellow object near the center may be the first prenatal example of a globular cluster ever identified. It is surrounded by a giant molecular cloud.
Johnson and her colleagues spotted the bizarre object, which they call the "Firecracker," using the Atacama Large Millimeter/submillimeter Array (ALMA) in the Atacama desert in Chile. It's located inside a pair of interacting galaxies known to scientists as NGC 4038/NGC 4039, or The Antennae Galaxies.
The Firecracker has a mass that's 50 times that of our sun, and is under an enormous amount of pressure -- roughly 10,000 times greater than the average pressure in interstellar space. According to the researchers, this makes it a good candidate for collapsing into a globular cluster within the next million years.
What do other scientists make of the discovery? Dr. Alison Peck, ALMA scientist at the National Radio Astronomy Observatory, who was not involved in the new research, called it "important" and said she was "really excited to hear about these results." She told The Huffington Post in an email:
"One of the things that we all yearn to understand is how our surroundings formed, how our galaxy and our solar system came to be. To do this, since we can’t actually watch things change over time, (it just takes too long), we need to find similar objects at different stages of development and compare them. What Dr. Johnson’s team have found here is an analog of an object that we look for in the very early universe, but they’ve found it so close by that we’ll be able to make extremely detailed observations and find out much more about the physical conditions in this exciting region."
The research is set to be published in the Astrophysical Journal.