Spain’s Discovery: Magnetars Power Superluminous Supernovae

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Spain’s Role in Cracking the Supernova Code

Researchers at ICE-CSIC in Barcelona played a pivotal role in interpreting data from NASA’s Fermi telescope, which has been scanning the cosmos for gamma rays since 2008. Guillem Martí-Devesa, a key investigator, explained that the team focused on the six closest superluminous supernovae observed in the first 16 years of Fermi’s mission. Only one—SN 2017egm—showed definitive evidence of gamma rays, a signal that had eluded astronomers for nearly 20 years. “Only SN 2017egm shows evidence of gamma rays, confirming that some supernovas can be as luminous in gamma rays as in visible light,” Martí-Devesa said. This breakthrough opens a new window into studying these extreme cosmic events, which can outshine ordinary supernovas by a factor of ten. The discovery is particularly significant because it resolves a long-standing puzzle: what powers these superluminous explosions? The answer, according to the team, lies in the birth of a magnetar—a rapidly spinning, super-magnetized neutron star formed during the star’s collapse. These objects act like cosmic dynamos, injecting energy into the explosion and sustaining its brilliance for months.

A Magnetar’s Hidden Hand in Stellar Explosions

The team’s analysis, published in Astronomy & Astrophysics, compared optical and gamma-ray observations of SN 2017egm with theoretical models. The magnetar hypothesis fits the data best: the supernova’s initial burst of light and the delayed arrival of gamma rays—detected about three months after the explosion—align with predictions for a newborn magnetar spinning hundreds of times per second. “This model of a magnetar reproduces the luminosity of the supernova and the timing of its gamma rays during the first months,” said Fabio Acero, the study’s lead author and a researcher at the University of Paris-Saclay. “However, we see room for improvement in later stages, when the visible light fades irregularly.” The team suggests that other processes, such as falling debris or interactions with pre-explosion stellar material, may also influence how these supernovas dim over time. The findings build on a 2024 study by Li Shang at the University of Anhui, which first proposed that Fermi’s Large Area Telescope (LAT) might have detected gamma rays from SN 2017egm. The new research solidifies that suspicion, marking the first definitive detection of gamma rays from a superluminous supernova.

What This Means for Our Understanding of the Cosmos

For decades, astronomers have searched Fermi’s data for gamma-ray signals from supernovas, but none were conclusive—until now. The confirmation of gamma rays from SN 2017egm not only validates the magnetar theory but also provides a new tool for studying these rare events. Superluminous supernovas, which occur when massive stars collapse, are key to understanding extreme physics in the universe, including how particles are accelerated to near-light speeds and how energy is distributed in the aftermath of such cataclysmic events. “During nearly 20 years, astronomers have searched Fermi’s data for gamma-ray signals from thousands of supernovas, but none were definitive until now,” Acero said. The detection of gamma rays from SN 2017egm changes the game, offering a direct window into the heart of these explosions and the exotic objects that power them. The implications extend beyond supernovas. Magnetars are also linked to other high-energy phenomena, such as fast radio bursts and gamma-ray bursts. By studying how these objects influence supernovae, scientists may gain insights into the broader workings of the universe, from the life cycles of stars to the origins of cosmic rays.

The Road Ahead: What’s Next for Supernova Research?

With this discovery, astronomers now have a clearer picture of how some of the universe’s most luminous explosions are powered. The next steps involve refining models to explain the later stages of these supernovas, when the light fades irregularly. Researchers will also look for similar gamma-ray signatures in other superluminous supernovas, potentially uncovering more magnetars and deepening our understanding of these cosmic powerhouses. The confirmation of gamma rays from SN 2017egm is a testament to the power of international collaboration and advanced technology. As Fermi continues to scan the skies, and as new telescopes come online, the mystery of superluminous supernovas may soon yield even more surprises. For now, the universe has spoken: some of its brightest explosions are fueled by the most extreme objects known to science—magnetars, the cosmic dynamos hiding in the heart of stellar cataclysms.

Sources: El Confidencial, Libertad Digital, Europa Press, <a href="https://www.abc.com.

<!– /wp:paragraph This breakthrough highlights the importance of global scientific efforts in unlocking the secrets of magnetars and their role in superluminous supernovas.