Podcaster: Richard Drumm
Title: UNAWE Space Scoop – Fast and Furious Starring Dual Quasars
Organization: 365 Days Of Astronomy
Link : http://365daysofastronomy.org/ ; https://spacescoop.org/en/scoops/2311/fast-and-furious-starring-dual-quasars/
Description: Space scoop, news for children.
Astronomers describe ‘cosmic noon’ as a dramatic period in the history of our Universe when it was buzzing with galaxy mergers and furious star formation.
Observing these mergers has been relatively rare and challenging, since the Universe was very young back when the mergers were happening. The Universe was only three billion years old then, so this was about 7 billion years ago.
Bio: Richard Drumm is President of the Charlottesville Astronomical Society and President of 3D – Drumm Digital Design, a video production company with clients such as Kodak, Xerox and GlaxoSmithKline Pharmaceuticals. He was an observer with the UVa Parallax Program at McCormick Observatory in 1981 & 1982. He has found that his greatest passion in life is public outreach astronomy and he pursues it at every opportunity.
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Transcript:
This is the 365 Days of Astronomy Podcast. Today we bring you a new episode in our Space Scoop series. This show is produced in collaboration with Universe Awareness, a program that strives to inspire every child with our wonderful cosmos.
Today’s story is…
Fast and Furious Starring Dual Quasars
Astronomers describe ‘cosmic noon’ as a dramatic period in the history of our Universe when it was buzzing with galaxy mergers and furious star formation.
Observing these mergers has been relatively rare and challenging, since the Universe was very young back when the mergers were happening.
The Universe was only three billion years old then, so this was about 7 billion years ago.
Astronomers from the University of Illinois at Urbana-Champaign found evidence of such a ‘cosmic noon’ merger for the first time by detecting a pair of energetic quasars in the same galactic neighborhood.
The galaxy is called SDSS J0749 + 2255, which is a mouthful.
Let’s just call it 2255.
Galaxies grow and evolve by merging with other galaxies.
When galaxies merge, they blend together their billions of stars into a new galaxy.
And a lot of new stars are born from that merger!
There’s lots of empty space between the stars of a galaxy, so the galaxies pass through each other without any stars colliding with other stars.
But there is gas between the stars and the gas clouds do collide.
This is how all that star formation happens.
In some cases, these energetic mergers can provide enough gaseous food for the growing SMBH at the galaxy’s center, and this is happening to 2255!
This makes it so active that it releases bright, energetic electromagnetic radiation all across the spectrum.
Astronomers call such bright objects quasars.
Using powerful ground and space-based telescopes, including NOIRLab’s Gemini North telescope in Hawai‘i, that team of astronomers found not one but two quasars very close to each other.
And, to top it all off, they’re only 10,000 light-years apart!
ESA’s Gaia space observatory was the first to detect 2255.
Then NASA’s Hubble space telescope was used to confirm that this was two SMBHs and not a chance alignment of an SMBH and a foreground star or a background galaxy.
These galaxies apparently are on their way to merging into a giant elliptical galaxy.
Finding such a system of two SMBHs so close to each other in the early universe is quite tricky.
It’s a bit like finding a needle in a haystack.
For one, it is difficult to tell the two black holes apart, as they need to be actively feeding on material and shining as quasars simultaneously, which is rare.
To verify their discovery, astronomers used the Gemini Multi-Object Spectrograph, GMOS and the GNIRS Infrared Spectrograph on the Gemini North telescope.
These instruments calculated how far the SMBHs are from each other and confirmed that the two objects were both quasars.
The team conducted further studies with the W.M. Keck Observatory, the NSF’s Karl G. Jansky Very Large Array, and NASA’s Chandra X-ray Observatory to confirm the observations.
Astronomers now look forward to studying in detail how galaxies evolve at cosmic noon, how supermassive black holes grow in the early universe, and how frequently galaxy mergers occur.
Hey, here’s a cook fact!
Galactic mergers can produce bright quasars that outshine the entire galaxy.
Some of these mergers will become massive elliptical galaxies that contain black holes that are many billions of times the mass of our Sun.
Data shows that for every 100 SMBHs, only one should be actively eating at a given time, making the discovery of these dual quasars extremely rare and more than a little fascinating!
Because telescopes that look far out in space are looking into the far past, these two quasars have, after 7 billion years, surely merged into a bigger SMBH and 2255 is now an elliptical galaxy.
We’ll just have to wait for a few billion years to see the result!
Thank you for listening to the 365 Days of Astronomy Podcast!
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365 Days of Astronomy
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