Physicists solve puzzle about ancient galaxy found by Webb telescope

Final September, the James Webb House Telescope, or JWST, found JWST-ER1g, a large historic galaxy that fashioned when the universe was only a quarter of its present age. Surprisingly, an Einstein ring is related to this galaxy. That is as a result of JWST-ER1g acts as a lens and bends gentle from a distant supply, which then seems as a hoop—a phenomenon referred to as sturdy gravitational lensing, predicted in Einstein’s principle of normal relativity.

The total mass enclosed throughout the ring has two parts: stellar and dark matter parts.

“If we subtract the stellar mass from the total mass, we get the dark matter mass throughout the ring,” mentioned Hai-Bo Yu, a professor of physics and astronomy on the College of California, Riverside, whose group has printed new work about JWST-ER1g within the journal The Astrophysical Journal Letters. “However the worth for the dark matter mass appears greater than anticipated. That is puzzling. In our paper, we provide a proof.”

A dark matter halo is the halo of invisible matter that permeates and surrounds a galaxy like JWST-ER1g. Though dark matter has by no means been detected in laboratories, physicists are assured dark matter, which makes up 85% of the universe’s matter, exists.

“When peculiar matter—pristine gasoline and stars—collapses and condenses into the dark matter halo of JWST-ER1g, it might be compressing the halo, resulting in a excessive density,” mentioned Demao Kong, a second-year graduate pupil at UCR, who led the evaluation. “Our numerical research present that this mechanism can clarify the excessive dark matter density of JWST-ER1g—extra dark matter mass in the identical quantity, leading to greater density.”

In line with Daneng Yang, a postdoctoral researcher at UCR and co-author on the paper, JWST-ER1g, fashioned 3.4 billion years after the Huge Bang, offers “an ideal probability to study dark matter.”

“This sturdy lensing object is exclusive as a result of it has an ideal Einstein ring, from which we are able to get hold of priceless details about the total mass throughout the ring, a important step for testing dark matter properties,” he mentioned.

Launched on Christmas Day in 2021, NASA’s JWST is an orbiting infrared observatory. Additionally referred to as Webb, it’s designed to reply questions concerning the universe. It’s the largest, most complicated, and strongest space telescope ever constructed.

“JWST offers an unprecedented alternative for us to look at historic galaxies fashioned when the universe was younger,” Yu mentioned. “We count on to see extra surprises from JWST and be taught extra about dark matter quickly.”

The examine was supported by the John Templeton Basis and the U.S. Division of Power.

The title of the open access research paper is “Chilly Darkish Matter and Self-interacting Darkish Matter Interpretations of the Sturdy Gravitational Lensing Object JWST-ER1.”