Fast Radio Burst 121102 (Audio Analysis)
Burst Traced Back to Its Home Galaxy
Astronomers using the Deep Synoptic Array-10 at the Owens Valley Radio Observatory have discovered a new non-repeating fast radio burst (FRB), called FRB 190523, and, together with the W. M. Keck Observatory in Hawaii, have pinpointed its origins to a massive galaxy approximately 8 billion light-years away.
An artist’s impression of a radio telescope detecting a fast radio burst. Image credit: Swinburne University of Technology / OzGrav ARC Centre of Excellence.
Before this discovery, only two other bursts — the non-repeating FRB 180924and the repeater FRB 121102 — had been localized to a host galaxy.
In 2017, FRB 121102 was pinpointed to a galaxy lying 3 billion light-years away. In June 2019, FRB 180924 was traced to a massive galaxy about 4 billion light-years away.
“Finding the locations of the one-off FRBs is challenging because it requires a radio telescope that can both discover these extremely short events and locate them with the resolving power of a mile-wide radio dish,” said Caltech’s Dr. Vikram Ravi, who works with the Deep Synoptic Array-10 (DSA-10) at the Owens Valley Radio Observatory, which is situated east of the Sierra Nevada mountains in California.
“We built a new array of ten 4.5-m dishes that collectively act like a mile-wide dish to cover an area on the sky the size of 150 full moons. To do this, a powerful digital system ingests and processes an amount of data equivalent to a DVD every second.”
DSA-10 searches for fast radio bursts within a sky-area the size of 150 full moons (left); within this area, it can locate these bursts with immense resolving power, isolating them to regions containing just one galaxy (middle); the right panel shows the time profile of FRB 190523 above its radio spectrum. Image credit: Caltech / Owens Valley Radio Observatory / V. Ravi.
FRB 190523’s host galaxy is a massive galaxy similar to our Milky Way.
“This finding tells us that every galaxy, even a run-of-the-mill galaxy like our Milky Way, can generate an FRB,” Dr. Ravi said.
The discovery also suggests that a leading theory for what causes FRBs — the eruption of plasma from magnetars — may need to be rethought.
“The theory that FRBs come from magnetars was developed in part because the earlier FRB 121102 came from an active star-forming environment, where young magnetars can be formed in the supernovae of massive stars. But the host galaxy of FRB 190523 is more mellow in comparison,” Dr. Ravi said.
The findings appear in the journal Nature.
_____
V. Ravi et al. A fast radio burst localized to a massive galaxy. Nature, published online July 2, 2019; doi: 10.1038/s41586-019-1389-7
Nenhum comentário:
Postar um comentário