Astronomers Apparently Seen Another Epic Accident of Neutron Stars – And They Did not Need gravitational waves do that.
NASA's Chandra X-ray Observatory has detected a powerful X-ray burst from a galaxy 6.6 billion light years from Earth, according to a new study. The issue, according to the researchers, was probably generated by the merger of two neutron stars, exotic stellar corpses so dense that their constituent matter is crushed into neutrons.
If this interpretation is correct, it will open up new paths in the search for neutron star collisions, said study team members. Although there is another strong candidate, only one such event has been confirmed to date: a 2017 discovery that relied heavily on the detection of space-time ripples known as gravitational waves. (Several different telescopes observed the light of this accident as well, opening the era of "multimission astronomy".)
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"We found a completely new way of identifying a fusion of neutron stars," said lead author Yongquan Xue of the University of Science and Technology of China. said in a statement.. "The behavior of this x-ray source matches what one of our team members predicted for those events."
The light source studied by Chandra, dubbed XT2, exploded on March 22, 2015, but the research team saw it later after passing through the data from the observatory archive. The X-ray brightness of the XT2 remained relatively constant for 30 minutes. But that brightness fell by a factor of 300 over the next 6.5 hours and then completely disappeared.
This X-ray signature, according to the researchers, coincides with that of a newborn magnetar, a fast-spinning neutron star with a magnetic field about a quadrillion times more powerful than Earth's. So it seems that the clash of XT2 neutron stars has created a magnetar instead of a black hole, as well as the 2017 event (which is known as GW170817 because it was first seen on August 17, 2017).
The new study should help astronomers learn more about the internal structure of neutron stars, team members said.
"We can not throw neutron stars together in a lab to see what happens, so we have to wait until the universe does it for us," said co-author Bing Zhang of the University of Nevada in Las Vegas. declaration. "If two neutron stars can collide and a heavy neutron star survives, it tells us that its structure is relatively rigid and resilient."
The XT2 probably also generated gravitational waves, the researchers said. But the event occurred before the release of the updated version of Observatory of Gravitational Waves with Laser Interferometer (LIGO) This design, along with a sister effort known as Virgo, sighted the space-time ripples of GW170817. And XT2 is probably a long way from being tested by LIGO, said study team members.
If XT2 is indeed a fusion of neutron stars, it is a member of a very select group. But there may be others of that sort lurking in Chandra's files.
"We start looking at others Chandra Contact info to see if similar sources are present, "said co-author Xuechen Cheng, also from China's University of Science and Technology. As with this source, the data contained in the files may contain some unexpected treasures. "
The new study was published last week in the journal Nature. You can read it for free at the online prepress website arXiv.org.