An observatory in West Virginia picked up 15 bright radio pulses from a dwarf galaxy, 3 billion light years, earlier this year. The initial results, based on observations carried out by a team of astronomers and astrophysicists, postulate these pulses to have emerged from an unknown source, labeled as FRB 121102. It’s a source of fast radio bursts (FRBs).

They were first detected in 2001, and as the name suggests, FRBs are super-fast and really powerful burst of radio signals. But we still have no idea what causes them. 

"The repeating FRB source is an anomaly in the population right now; it's the only one of its kind," says Emily Petroff, a post-doctoral researcher at the Netherlands Institute for Radio Astronomy. However, Petroff was not directly involved in the current observations.  

"We're trying hard to find more (either by checking to see if other FRBs repeat, or trying to find more FRBs and monitor them)," Petroff wrote in an email. "Keep in mind that the population is still really small. Only 30 FRB sources have been found, from 29 of those we've only seen one burst, from one of them we've seen over 200!"

It's thrilling to have 15 bursts from apparently the same source, coming with a higher frequency than usual; 7 Gigahertz. Andrew Siemion, an astrophysicist and director of the Breakthrough Listen program, stated “Bursts from this source have never been seen at this high a frequency”.

Breakthrough Listen organization, funding the project, issued a press release saying “Possible explanations for FRBs range from outbursts from rotating neutron stars with extremely strong magnetic fields, to more speculative ideas that they are directed energy sources used by extraterrestrial civilizations to power spacecraft.”

It’s their job to bring up aliens as a possibility until they have something else to count on. To begin with aliens bumping in this whole scenario might seem strange but not if the news is coming from a $100 million project with its main objective to look for signals from extraterrestrial civilizations.

There are a number of other possible explanations for these repeating bursts, and most of them definitely not include aliens.

A sequence of the 15 bursts observed last weekend. Credit Siemion et al.

"With any mystery signal from space comes the inevitable question about extraterrestrial life. At the moment there's no evidence that these are encoded messages or anything like that," Petroff says. "And when dealing with a new phenomenon, the simplest explanations—such as emission from an astrophysical source (and not a spaceship)—are usually the best place to start."

It could be the last spinning remnant of a star turned supernova. These neutron stars can sometimes hurl out bright pulses into the universe, or have magnetic fields so powerful that they earn the name Magnetars. Some scientists think that FRB’s could be emitted early on in a magnetar's development.

"Most of the current theories for FRBs are centered around compact, energetic objects in other galaxies," Petroff says. "The two most compact and energetic things we know about are black holes and neutron stars; they also happen to be two of the most extreme types of objects in the universe. At the moment there are more theories than there are FRB sources, though.” Petroff further added, “The last time we had a cosmic mystery source like this was with the reporting of the discovery of gamma ray bursts in the 1970s, then it took decades to figure out what caused them and their origin.”

Continuing to observe FRBs can help get more data, and maybe eventually we’ll figure out what they are. Lots of new telescopes are coming online in the next 6 to 12 months to further probe these FRBs. The fact that we are learning more about the magnificently baffling universe is exhilarating itself.  

On Christmas Eve 2016, Andrew Seymour, an astronomer at the Arecibo Observatory in Puerto Rico, kissed his 4-year-old daughter, Cora Lee, goodnight, telling her he was off to track Santa. He walked to the well-worn telescope, occasionally passing revelers riding horses through the empty streets — a common sight in Arecibo during the holidays. Sometimes a lonely firework would light up in the distance. Close to midnight, he nodded to a guard and entered the nearly empty complex.

The radio dish was on a break from its regular schedule, so Seymour decided to test out new hardware that he and his colleagues had been working on, writes Katia Moskvitch in Quanta Magazine. Soon after he began recording his observations, an extremely powerful radio source, 3 billion light-years away, decided to say hello. Seymour didn’t find Santa that Christmas, but rather an unexpected twist in the tale of one of the most mysterious objects in the cosmos.

The object that Seymour caught that night was the only known repeating fast radio burst(FRB), an ultra-brief flash of energy that flickers on and off at uneven intervals. Astronomers had been debating what might be causing the mysterious repeater, officially called FRB 121102 and unofficially the “Spitler burst,” after the astronomer who discovered it.

In the weeks following that Christmas detection, Arecibo registered 15 more bursts from this one source. These flashes were the highest frequency FRBs ever captured at the time, a measurement made possible by the hardware Seymour and his team had just installed. Based on the new information, the scientists have concluded in a study released in the journal Nature that whatever object is creating the bursts, it must be in a very odd and extreme cosmic neighborhood, something akin to the environment surrounding a black hole with a mass of more than 10,000 suns.

The new work helps to strengthen the theory that at least some FRBs might be produced by magnetars — highly magnetized, rotating neutron stars, which are the extremely dense remains of massive stars that have gone supernova, said Shami Chatterjee, an astrophysicist at Cornell University. In the case of the repeater, it could be a neutron star “that lives in the environment of a massive black hole,” he said. Or it might also be like nothing we’ve seen before — a different kind of magnetar ensconced in a very intense, magnetically dense birth nebula, unlike any known to exist in our galaxy — “quite extraordinary circumstances,” he said.

Read more here...

Source and reference: Quanta Magazine