In an ejection that would have caused its rotation to slow, a magnetar is depicted losing material into space in this artist’s concept. The magnetar’s strong, twisted magnetic field lines (shown in green) can influence the flow of electrically charged material from the object, which is a type of neutron star. Credit: NASA/JPL-Caltech

What’s causing mysterious bursts of radio waves from deep space? Astronomers may be a step closer to providing one answer to that question. Two NASA X-ray telescopes recently observed one of such events—known as a fast radio burst—mere minutes before and after it occurred. This unprecedented view sets scientists on a path to understand these extreme radio events better.

While they only last for a fraction of a second, fast radio bursts can release about as much energy as the sun does in a year. Their light also forms a laser-like beam, setting them apart from more chaotic cosmic explosions.

Because the bursts are so brief, it’s often hard to pinpoint where they come from. Prior to 2020, those that were traced to their source originated outside our own galaxy—too far away for astronomers to see what created them. Then a fast radio burst erupted in Earth’s home galaxy, originating from an extremely dense object called a magnetar—the collapsed remains of an exploded star.

In October 2022, the same magnetar—called SGR 1935+2154—produced another fast radio burst, this one studied in detail by NASA’s NICER (Neutron Star Interior Composition Explorer) on the International Space Station and NuSTAR (Nuclear Spectroscopic Telescope Array) in low Earth orbit.

The telescopes observed the magnetar for hours, catching a glimpse of what happened on the surface of the source object and in its immediate surroundings before and after the fast radio burst. The results, described in a new study published in the journal Nature, are an example of how NASA telescopes can work together to observe and follow up on short-lived events in the cosmos.

The burst occurred between two “glitches” when the magnetar suddenly started spinning faster. SGR 1935+2154 is estimated to be about 12 miles (20 kilometers) across and spinning about 3.2 times per second, meaning its surface was moving at about 7,000 mph (11,000 kph). Slowing it down or speeding it up would require a significant amount of energy.

That’s why study authors were surprised to see that in between glitches, the magnetar slowed down to less than its pre-glitch speed in just nine hours, or about 100 times more rapidly than has ever been observed in a magnetar.

“Typically, when glitches happen, it takes the magnetar weeks or months to get back to its normal speed,” said Chin-Ping Hu, an astrophysicist at National Changhua University of Education in Taiwan and the lead author of the new study. “So clearly, things are happening with these objects on much shorter time scales than we previously thought, and that might be related to how fast radio bursts are generated.”

Spin cycle

When trying to piece together exactly how magnetars produce fast radio bursts, scientists have a lot of variables to consider.

For example, magnetars (which are a type of neutron star) are so dense that a teaspoon of their material would weigh about a billion tons on Earth. Such a high density also means a strong gravitational pull: A marshmallow falling onto a typical neutron star would impact with the force of an early atomic bomb.

The strong gravity means the surface of a magnetar is a volatile place, regularly releasing bursts of X-rays and higher-energy light. Before the fast radio burst that occurred in 2022, the magnetar started releasing eruptions of X-rays and gamma rays (even more energetic wavelengths of light) that were observed in the peripheral vision of high-energy space telescopes. This increase in activity prompted mission operators to point NICER and NuSTAR directly at the magnetar.

“All those X-ray bursts that happened before this glitch would have had, in principle, enough energy to create a fast radio burst, but they didn’t,” said study co-author Zorawar Wadiasingh, a research scientist at the University of Maryland, College Park and NASA’s Goddard Space Flight Center. “So it seems like something changed during the slowdown period, creating the right set of conditions.”

What else might have happened with SGR 1935+2154 to produce a fast radio burst? One factor might be that the exterior of a magnetar is solid, and the high density crushes the interior into a state called a superfluid. Occasionally, the two can get out of sync, like water sloshing around inside a spinning fishbowl. When this happens, the fluid can deliver energy to the crust. The paper authors think this is likely what caused both glitches that bookended the fast radio burst.

If the initial glitch caused a crack in the magnetar’s surface, it might have released material from the star’s interior into space like a volcanic eruption. Losing mass causes spinning objects to slow down, so the researchers think this could explain the magnetar’s rapid deceleration.

But having observed only one of these events in real time, the team still can’t say for sure which of these factors (or others, such as the magnetar‘s powerful magnetic field) might lead to the production of a fast radio burst. Some might not be connected to the burst at all.

“We’ve unquestionably observed something important for our understanding of fast radio bursts,” said George Younes, a researcher at Goddard and a member of the NICER science team specializing in magnetars. “But I think we still need a lot more data to complete the mystery.”

JWST-7329: a rare massive galaxy that formed very early in the Universe. This JWST NIRCAM image shows a red disk galaxy but with images alone it is hard to distinguish from other objects. Spectral analysis of its light with JWST revealed its anomalous nature – it formed around 13 billions years ago even though it contains ~4x more mass in stars than our Milky Way does today. Credit: James Webb Space Telescope

Our understanding of how galaxies form and the nature of dark matter could be completely upended after new observations of a stellar population bigger than the Milky Way from more than 11 billion years ago that should not exist.

A paper published today in Nature details findings using new data from the James Webb Space Telescope (JWST). The results find that a massive galaxy in the early universe—observed 11.5 billion years ago (a cosmic redshift of 3.2)—has an extremely old population of stars formed much earlier—1.5 billion years earlier in time (a redshift of around 11). The observation upends current modeling, as not enough dark matter has built up in sufficient concentrations to seed their formation.

Swinburne University of Technology’s Distinguished Professor Karl Glazebrook led the study and the international team, who used the JWST for spectroscopic observations of this massive quiescent galaxy.

“We’ve been chasing this particular galaxy for seven years and spent hours observing it with the two largest telescopes on earth to figure out how old it was. But it was too red and too faint, and we couldn’t measure it. In the end, we had to go off Earth and use the JWST to confirm its nature.”

The formation of galaxies is a fundamental paradigm underpinning modern astrophysics and predicts a strong decline in the number of massive galaxies in early cosmic times. Extremely massive quiescent galaxies have now been observed as early as one to two billion years after the Big Bang which challenges previous theoretical models.

Distinguished Professor Glazebrook worked with leading researchers all over the world, including Dr. Themiya Nanayakkara, Dr. Lalitwadee Kawinwanichakij, Dr. Colin Jacobs, Dr. Harry Chittenden, Associate Professor Glenn G Kacprzak and Associate Professor Ivo Labbe from Swinburne’s Centre for Astrophysics and Supercomputing.

“This was very much a team effort, from the infrared sky surveys we started in 2010 that led to us identifying this galaxy as unusual, to our many hours on the Keck and Very Large Telescope where we tried, but failed to confirm it, until finally the last year where we spent enormous effort figuring out how to process the JWST data and analyze this spectrum.”

Dr. Themiya Nanayakkara, who led the spectral analysis of the JWST data, says, “We are now going beyond what was possible to confirm the oldest massive quiescent monsters that exist deep in the universe. This pushes the boundaries of our current understanding of how galaxies form and evolve. The key question now is how they form so fast very early in the universe, and what mysterious mechanisms lead to stopping them forming stars abruptly when the rest of the universe doing so.”

Associate Professor Claudia Lagos from The University of Western Australia node of the International Centre for Radio Astronomy Research (ICRAR) was crucial in developing the theoretical modeling of the evolution of dark matter concentrations for the study.

“Galaxy formation is in large part dictated by how dark matter concentrates,” she says. “Having these extremely massive galaxies so early in the universe is posing significant challenges to our standard model of cosmology. This is because we don’t think such massive dark matter structures as to host these massive galaxies have had time yet to form. More observations are needed to understand how common these galaxies may be and to help us understand how truly massive these galaxies are.”

Glazebrook hopes this could be a new opening for our understanding of the physics of dark matter, stating, “JWST has been finding increasing evidence for massive galaxies forming early in time. This result sets a new record for this phenomenon. Although it is very striking, it is only one object. But we hope to find more, and if we do, this will really upset our ideas of galaxy formation.”

by Breck Carter   , Swinburne University of Technology

University of Michigan researchers are celebrating their discovery of a new plant biochemistry and its unusual ability to form cyclic peptides—molecules that hold promise in pharmaceuticals as they can bind to challenging drug targets.

Cyclic peptides are an emerging and promising area of drug research.

The new study, led by U-M College of Pharmacy researchers Lisa Mydy and Roland Kersten, revealed a mechanism by which plants generate cyclic peptides. The research is published in the journal Nature Chemical Biology.

Mydy identified the new plant protein fold and its novel chemistry, which she said had never been seen before. The protein can generate cyclic peptides, one of which holds potential as an anti-cancer drug.

“It’s extremely exciting,” said Mydy, a postdoctoral research fellow in the Department of Medicinal Chemistry. “This type of discovery doesn’t happen too often.”

Mydy and colleagues studied the biosynthesis of a class of macrocyclic peptides found in plants and known for their potential use as therapeutic drugs. They identified a “fascinating new protein fold that has a really unusual mechanism to form cyclic peptides. It is a new biochemistry that we have not seen before,” Mydy said.

The researchers also examined peptide cyclase, a protein called AhyBURP found in the roots of the peanut plant, a representative of the founding Unknown Seed Protein, or USP-type, which in turn is part of the BURP-domain protein family.

“There was no experimental information on our protein AhyBURP,” Mydy said. “The only hint we had for function was that the protein needed copper to cyclize a peptide.”

The research team studied the protein structures with X-ray crystallography and used the Advanced Photon Source at Argonne National Laboratory. In the process, they found that the “protein AhyBURP uses copper and oxygen in a unique way that we’re still investigating,” Mydy said.

“Most cyclic peptides need another enzyme to come in and do the cyclization chemistry,” she said. “However, AhyBURP can do it within the same protein on itself. Other copper-dependent proteins function by attaching oxygen somewhere on the peptide. We don’t observe that, and we want to know why. I see this as the first example of this type of chemistry that can happen with copper and oxygen within a protein.”

The discovery of the new protein grew from ongoing work in Kersten’s lab. As part of the U-M Natural Product Discovery Initiative, the Kersten lab aims to discover and research new plant-based chemicals that can become drugs and ultimately cure human diseases.

“We use a modern approach where we screen the genetic sequences of plants, searching for genes connected to new chemistry,” said Kersten, assistant professor of medicinal chemistry at the College of Pharmacy. “That’s how we identified the cyclic peptide products and their underlying proteins as a target of interest.”

This class of peptides is of interest because their cyclization properties make them more structured and stable, increasing their potential to be used as drugs.

Many drugs, including chemicals derived from living organisms, are cyclic, meaning that they can bind drug targets and remain intact in a patient for a desired time. Nature has evolved many biochemical solutions to produce such cyclic molecules.

Kersten has isolated other compounds made by the same protein family that have been shown to have suppressing effects on lung cancer cells in lab tests, so there is growing hope that this discovery will have potential as a future anti-cancer agent.

“Now that we know what the protein looks like for one of the BURP-domain proteins, we can test more ideas about how the protein may influence the chemical reaction between the peptide, copper and oxygen to form cyclic peptides,” said Mydy, a structural biologist and enzymologist by training.

“It is a fantastic and challenging puzzle to figure out why this is happening and understand the structure. It’s extremely exciting to be part of this type of discovery that may eventually lead to effective pharmaceutical therapeutics.”