- Scientists discovered an enormous outburst of gamma rays from the galaxy M82, 12 million light-years away.
- The commentary didn’t match with typical gamma ray bursts, and astronomers discovered no afterglow in seen mild to X-rays. Plus, they didn’t detect any gravity waves both.
- Now researchers have concluded the occasion originated from a magnetar within the galaxy M82. That is the primary magnetar eruption we’ve ever seen in one other galaxy! Magnetars are a kind of neutron star, however with vastly extra highly effective magnetic fields.
Large outburst of gamma rays in close by galaxy
On November 15, 2023, the European INTEGRAL space observatory detected an enormous burst of gamma rays coming from the close by galaxy M82, which is 12 million light-years from Earth. The eruption lasted for just one/10 of a second. What was it? A staff of European astronomers said on April 24, 2024, that it originated from an enormous magnetar eruption in that galaxy.
Magnetars are an unique sort of younger neutron star with extraordinarily highly effective magnetic fields. The magnetic discipline is about 10,000 occasions stronger than a standard neutron star and a few trillion occasions stronger than Earth’s! Solely three such large flares have been recognized in our personal galaxy prior to now 50 years. And now now we have the primary one confirmed from exterior our galaxy.
The peer-reviewed discovery was published within the journal Nature on April 24, 2024. The paper can be accessible free as a preprint on arXiv.
Big gamma ray eruption transient however highly effective
The large outburst of gamma rays was intense however transient, lasting just one/10 of a second. Lead creator Sandro Mereghetti on the Nationwide Institute for Astrophysics (INAF–IASF) in Milan, Italy, said:
We instantly realized that this was a particular alert. Gamma-ray bursts come from distant and anyplace within the sky, however this burst got here from a shiny close by galaxy.
Extremely, the Integral Burst Alert System (IBAS) mechanically despatched out the gamma ray burst notification to different astronomers solely 13 seconds after INTEGRAL initially detected the eruption. Carlo Ferrigno, senior analysis affiliate on the College of Geneva (UNIGE) College of Science, and co-author of the paper, mentioned:
The satellite knowledge had been acquired within the INTEGRAL Science Information Centre (ISDC), based mostly on the Ecogia web site of the UNIGE Astronomy Division, from the place a gamma-ray burst alert was despatched out to astronomers worldwide, solely 13 seconds after its detection.
Lack of afterglow and gravity waves
This allowed different astronomers to shortly observe up on the invention. This included utilizing the European Area Company’s XMM-Newton space telescope. The telescope looked for an afterglow – in each seen mild and X-rays – from the eruption however didn’t discover one. This narrowed down the doable explanations. Typically neutron stars collide, creating a brief gamma ray burst. However that will have created gravitational waves and left an afterglow.
The astronomers then additionally used the Telescopio Nazionale Galileo (TNG) in Italy, the Haute-Provence Observatory in France and different ground-based telescopes to seek for an afterglow in seen mild. Once more, nothing. As an alternative, the telescopes solely noticed the same old sizzling gasoline and stars present in galaxies.
No gravitational waves had been detected, both. If there had been any, the LIGO (U.S.), VIRGO (Italy) and KAGRA (Japan) gravity wave detectors ought to have picked them up.
Enormous magnetar eruption the perfect rationalization
There was one other chance that would clarify the shortage of an afterglow and gravity waves: magnetars. They’re a kind of neutron star, a really small dense stellar remnant of an enormous star that exploded in a supernova. Neutron stars rotate shortly and have highly effective magnetic fields. However the magnetic fields of magnetars are far more highly effective than these of typical neutron stars, as much as 10,000 occasions stronger. The truth is, they’re the strongest recognized magnetic fields of any objects within the universe. Because the paper stated:
Its spectral properties, together with the size of the burst, the bounds on its X-ray and optical counterparts obtained inside just a few hours, and the shortage of a gravitational wave sign, unambiguously qualify this burst as an enormous flare from a magnetar in M82.
FIrst magnetar eruption seen exterior the Milky Way
Magnetars launch power in explosive flares. And every so often these flares might be actually gigantic. They aren’t frequent, and astronomers have solely seen three such eruptions through the previous 50 years of observing gamma-ray bursts. Notably, all three got here from magnetars inside our personal galaxy. A kind of bursts, detected in 2004, originated on a magnetar 30,000 light-years from Earth. It was so highly effective that it even had an impact on Earth’s higher environment.
This new flare from galaxy M82 is just like these earlier detections. The massive distinction, nevertheless, is that this magnetar is in one other galaxy, 12 million light-years away. This additionally helps the speculation that magnetars are younger neutron stars, as Volodymyr Savchenko on the College of Geneva famous:
The invention of a magnetar on this area confirms that magnetars are seemingly younger neutron stars.
Astronomers will now proceed to seek for proof of extra magnetars exterior our galaxy.
A serendipitous discovery made simpler with INTEGRAL
It’s additionally noteworthy that this could have been a extra serendipitous discovery if one other gamma ray observatory had made the detection. INTEGRAL covers lots of the night time sky, an space about 3,000 occasions bigger than the moon. However most observatories must be pointed in the appropriate course on the proper time to catch such brief gamma ray bursts. INTEGRAL and XMM-Newton are additionally extra versatile of their schedules. This additionally helps them to have the ability to detect gamma ray bursts or different anomalies and alert astronomers a lot sooner.
Backside line: The European INTEGRAL satellite detected an enormous magnetar eruption of gamma rays. The uncommon, highly effective occasion of this measurement is the primary we’ve ever seen in one other galaxy.
Source: A magnetar giant flare in the nearby starburst galaxy M82
Source (preprint): A magnetar giant flare in the nearby starburst galaxy M82
Read more: Magnetars are the most powerful magnets in the universe
Read more: Magnetar slowed down by a volcano-like eruption?
