For the very first time, astronomers have definitively found a flaring magnetar in another galaxy.
These ultra-magnetic stellar corpses were believed to be responsible for some of the highest-energy explosions in the neighboring universe. Till this burst, no one might prove it, astronomers reported January 13 at the virtual meeting of the American Astronomical Society and in papers in Nature and Nature Astronomy
Astronomers have actually seen flaring magnetars in the Milky Way, but those are so intense that it’s impossible to get a great appearance at them. Possible peeks of flaring magnetars in other galaxies might have been identified in the past, too.
The very first sign of the magnetar showed up as a blast of X-rays and gamma rays on April15 Five telescopes in area, consisting of the Fermi Gamma-ray Space Telescope and the Mars Odyssey orbiter, observed the blast, providing scientists enough details to find its source: the galaxy NGC 253, or the Carver galaxy, 11.4 million light-years away.
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At first, astronomers thought that the blast was a kind of catastrophic explosion called a short gamma-ray burst, or GRB, which are usually brought on by clashing neutron stars or other devastating cosmic occasions.
However the signal looked odd for a brief GRB: It increased to peak brightness rapidly, within 2 milliseconds, trailed off for another 50 milliseconds and seemed over by about 140 milliseconds. As the signal faded, a few of the telescopes identified changes in the light that changed faster than a millisecond.
Typical short GRBs that arise from a neutron star crash don’t change like that, stated astrophysicist Oliver Roberts of the Universities Area Research Association in Huntsville, Ala. Flaring magnetars in our own galaxy do, when the bright spot where the flare was emitted comes in and out of view as the magnetar spins.
Then, surprisingly, the Fermi telescope caught gamma rays with energies higher than a gigaelectronvolt getting here four minutes after the preliminary blast. There is no other way for the known sources of short GRBs to do that.
” We have actually discovered a masquerading magnetar in a neighboring galaxy, and we have actually unmasked it,” said astrophysicist Kevin Hurley of the University of California, Berkeley at a Jan. 13 news briefing.
The scientists believe that the flare was set off by an enormous starquake, one thousand trillion trillion, or 1027, times as big as the 9.5 magnitude earthquake recorded in Chile in1960 The quake led the magnetar to launch a blob of plasma that sped away at nearly the speed of light, producing gamma rays and X-rays as it went.
The discovery suggests that a minimum of some signals that appear like short GRBs are in truth from magnetar flares, as astronomers have long believed ( SN: 11/ 3/10). It likewise means that three earlier events that astronomers had flagged as possible magnetar flares most likely were in fact from the allured excellent corpses, offering astronomers a population of magnetar flares to compare to each other.
The finding might have exciting implications for fast radio bursts, another mysterious cosmic signal that has had astronomers scratching their heads for over a decade. Numerous lines of proof connect quickly radio bursts to magnetars, including another signal originating from within the Milky Way that coincidentally also gotten here in April 2020 ( SN: 6/4/20).
” That [discovery] leant extra credence to fast radio bursts being [from] magnetars,” Kaspi states, though there are still issues with that theory.
Kaspi has compared the obvious frequency of magnetar flares in other galaxies to the frequency of quick radio bursts and discovered that the rates are comparable. “That argues that actually, most or all quick radio bursts might be magnetars … I do not think yet it’s the total service,” however it’s a good step, she says.