These curious signals are alien in origin, but we currently don’t know what these bursts are or what causes them. Some suspect they may be the death rattles of neutron stars or young magnetars, extremely dense star cores spinning in a magnetic field.
The eight new repeating FRBs detected by the Canadian Hydrogen Intensity Mapping Experiment (CHIME) radio telescope now bring the total number of known repeating FRBs to 10. These perplexing, ‘alien’ signals have captured humanity’s attention for over a decade, as the world’s best and brightest try to figure out both what they are and what causes them.
The majority of FRBs are only detected once and then they disappear, but a select few are repeaters which may provide unprecedented insights into the composition of our universe.
In January 2019, just one, FRB 121102, was known to flash repeatedly, though a second, FRB 180814, was discovered weeks later. In just a few short months, humanity has increased that number five-fold.
Scientists have also localized the eight new repeaters to known galaxies, determining their rough location by how dispersed the signal is. Researchers have also discovered that not all FRBs come from extreme gravity environments, which means that there could be several different classes of objects or events that create FRBs.
Furthermore, repeater flashes last longer than one-off bursts indicating there may be two distinct underlying mechanisms that create them. Repeat bursts get weaker and less frequent in what the researchers dub the ‘sad trombone’ effect.
Meanwhile, is the supermassive all-consuming Sagittarius A* preparing to gobble up our galaxy? Or is it more like a rare Yellowstone geyser going off?
A supermassive black hole in the center of the Milky Way just woke up and is flashing 75 times brighter than ever observed, after being quiet for more than 20 years, baffling astronomers.
Sagittarius A*, a supermassive blackhole, is normally low key with minimal fluctuation in brightness. Recently, however, it bloomed 75 times brighter than ever before for no apparent reason.
Earlier this year, Tuan Do, an astronomer at UCLA, and his team took observations of the galactic centre using the WM Keck Observatory in Hawaii over four nights. The team observed the bizarre flash on May 13, capturing it in a two-hour timelapse that condensed the phenomenon down to just a few seconds. The “unprecedented” findings have now been published in the Astrophysical Journal Letters.
As Do explains, the footage begins with Sgr A* at its brightest, meaning it could have been even brighter before the team started their observations. Astronomers are now collecting data to determine exactly what caused the sudden flare, although there are several theories.
“Maybe more gas is falling into the black hole and that leads to higher amounts of accretion, which leads to it being brighter,” Do told New Scientist. There’s also a possibility that the black hole finally got around to consuming a gas cloud, known as G2, that approached Sgr A* in 2014.
The ground-based Keck Observatory will continue observing the Milky Way center until it’s no longer visible from Earth at night. Meanwhile, many other space telescopes, Spitzer, Chandra, Swift, and ALMA, were also observing the galactic center recently, possibly collecting data that could help explain what Sgr A* is doing.