Far out cosmology: very early giant spirals (Introduction)

by David Turell , Saturday, January 14, 2023, 16:09 (677 days ago) @ David Turell

Giant spirals galaxies appeared early after the Big Bang:

https://www.universetoday.com/159515/new-jwst-image-shows-that-grand-spiral-galaxies-ha...

For the first time this week, photos from the James Webb Space Telescope (JWST) revealed that stellar bars were present in some galaxies as far back as 11 billion years ago. Stellar bars are a defining feature of about two-thirds of all spiral galaxies in the Universe, including our own Milky Way. The discovery has implications for astronomers’ understanding of galactic evolution, indicating that bars form very quickly and may persist for much of a galaxy’s lifespan, influencing its shape and structure.

Stellar bars are regions of intense star formations that radiate out from a galaxy’s core. Through the motion of inner orbiting stars, dust, and gas clouds, they build up as a wave of dense material that perpetuates itself and spreads slowly outward while pulling raw material inwards. These regions become stellar nurseries that churn out new stars at a rapid pace.

The new JWST images, presented by The University of Texas at Austin on January 5th, show six barred spiral galaxies over 8.4 million years old, two of which are older than 11 billion years (the oldest galaxy ever seen is around 13.4 billion years old).

***

JWST has an advantage over Hubble in observing extremely old and distant galaxies, partly because its larger mirror can collect more light from distant, dim objects. But it also has an advantage due to its use of infrared rather than optical wavelengths. Light from older and more distant objects is ‘red-shifted’ along the electromagnetic spectrum, meaning that JWST’s detectors can pick them up better than Hubble can.

“Bars solve the supply chain problem in galaxies,” Jogee says. “Just like we need to bring raw material from the harbor to inland factories that make new products, a bar powerfully transports gas into the central region where the gas is rapidly converted into new stars at a rate typically 10 to 100 times faster than in the rest of the galaxy…This discovery of early bars means galaxy evolution models now have a new pathway via bars to accelerate the production of new stars at early epochs.”

Comment: this shows how the universe evolved in early time after the Big Bang. Be sure to go to the site to see the images.