Astronomers have long wondered what triggers brief, brilliant blasts of radio waves from other galaxies. Now, new observations suggest these events, known as fast radio bursts, or FRBs for short, may emanate from two completely different phenomena.
For the first time, astronomers have identified the home galaxy of a one-off FRB. Until now, only the repeating FRB 121102 had been pegged to a particular galaxy — a tiny, highly active dwarf galaxy about 2.5 billion light-years away (SN: 2/4/17, p. 10). In contrast, the newly discovered lone FRB hailed from a much more massive and tranquil host, researchers report online June 27 Science.
“You have to be somewhat wary” about drawing broad conclusions from just the two examples, says Duncan Lorimer, an astrophysicist at West Virginia University in Morgantown who helped discover the first-ever FRB in 2007. Though not involved in the latest work, Lorimer says the new findings offer compelling evidence that a one-and-done FRB is a different animal than an FRB that flickers on and off.
Astronomers spotted the new FRB using the Australian Square Kilometer Array Pathfinder, a cadre of 36 radio dishes spread up to six kilometers apart in the Australian outback. By combining data from all these dishes using a technique called interferometry, astronomers pinpointed the FRBs location with much higher accuracy than they could have with observations from a single telescope (SN: 4/27/19, p. 7).
The new FRBs discovery was somewhat serendipitous. Scientists had already spent two weeks in September scouting for FRBs, with no luck. “We were just about to give the telescope back,” but the next person scheduled for telescope time called in sick, says Keith Bannister, a radio astronomer at Australias Commonwealth Science and Industrial Research Organization in Sydney. So the team got an extra observation day, and caught the 1.3-millisecond burst of radio waves. “In his honor, for being sick that day … we called the FRB Tony,” Bannister says.
Tony — officially named FRB 180924 for the date of its discovery — hailed from the galaxy DES J214425.25–405400.81, about 4 billion light-years away in the constellation Grus.
Home address[hhmc]
The FRB 180924, nicknamed “Tony,” came from a disk-shaped galaxy about 4 billion light-years away (yellow). To astronomers surprise, Tony (black circle) originated not from the active galactic center, but the outskirts of the galaxy — peripheral to about 90 percent of the disks starlight.
Compared with the repeating FRBs origin, “you couldnt think of two galaxies that are more different,” Bannister says. FRB 121102, which flickers on and off at seemingly erratic intervals, is nestled in a dense, highly magnetized region near the center of a faint dwarf galaxy that is furiously forging new stars. Tonys home, however, sits on the edge of a disk-shaped galaxy about the size of the Milky Way that is undergoing very little star formation.
That position, about 13,000 light-years from the galaxys center, surprised Bannisters team. “Centers of galaxies are usually exciting places” with energetic sources that could power something like an FRB, Bannister says, but Tony “seems to comeRead More – Source
[contf]
[contfnew]
science news
[contfnewc]
[contfnewc]
