Scientists suspect that there is a rapidly rotating, highly magnetic neutron star, or “pulsar”, at the center of the Milky Way. This discovery could change our understanding of how many of these extremely dead stars exist near Sagittarius A* (Sgr A*), the supermassive black hole at the center of our galaxy.
like everyone else neutron starPulsars are formed when a star with the mass of the Sun runs out of fuel for nuclear fusion and is no longer able to support itself against gravitational collapse. Although the area is milky way This location, called the galactic center, is expected to be full of pulsars, but they are difficult to spot because the center of our galaxy is so extreme, turbulent, and dense. However, radio waves are not blocked by this region as much as visible light or other forms of electromagnetic radiation.
Scientists involved in the study said they were surprised by how few pulsars were discovered. “Our survey is one of the most sensitive surveys ever conducted into the galactic center,” said Karen Perez, team leader at the Explorations of Extraterrestrial Intelligence (SETI) Institute. stated in a statement. “Assuming that the pulsar population at the galactic center is similar to the pulsar population in the broader Milky Way, we should be sensitive to about 10% of millisecond pulsars and 50% of standard slow pulsars.
“Despite this sensitivity, we only detected a single candidate, called Breakthrough Listening Pulsar (BLPSR), which remains under active investigation.”
Test Einstein in a space lighthouse
When a neutron star is formed by the gravitational collapse of the core of a massive star, an object with one to two times the mass is created. solar It is packed into a width of 12 miles (20 kilometers). Not only does this create the densest material in the known universe (a teaspoon of neutron star “matter” would weigh 10 million tons, about the same as 85,000 adult blue whales if brought to Earth), but it also Like an Olympic ice skater pulling his arm closer to speed up his rotation, the rapid contraction of the core of a neutron star can produce an object that spins at an astonishing 700 times a second.
As if this were not extreme enough for a neutron star, in the case of a pulsar, these dead stars emit two parallel radio emissions from their poles. As the pulsar rotates, these beams travel across space like rays from a lighthouse. Therefore, pulsars are often called “.space lighthouse. ”
The precision of pulsars means that the periodicity of their beams can be used as a cosmic clock, which can be used to investigate physics in extreme conditions, such as near celestial bodies with huge masses. This includes Einstein’s 1915 masterpiece, the theory of gravity, general relativity. This suggests that objects with mass distort the very fabric of space-time and become unified as a four-dimensional entity called “space-time.” Gravity arises from distortions in space, and the effects on time can be detected by sufficiently accurate clocks. A watch like a pulsar.
“External influences on the pulsar, such as the gravity of a massive object, can cause anomalies in the arrival of this stable pulse, which can be measured and modeled,” said team member Slavko Bogdanov of the Columbia Institute for Astrophysics. Relativity. ”
Sgr A*has a mass equivalent to more than 4 million suns and fundamentally influences space-time in its vicinity, so it is sure to provide a suitable laboratory for studying such physics. If pulsars exist in the immediate vicinity of Sgr A*, they serve as suitable experimental setups for these experiments.
the result, supermassive black hole. On the other hand, the fact that BLPSR was the only possible pulsar detected by galactic center researchers raises serious questions about the predicted population of these extreme dead stars at the center of the Milky Way.
These are questions that may be answered by future astronomy projects such as the Next Generation Very Large Array (ngVLA) and the Square Kilometer Array (SKA). These projects will need to have the sensitivity and resolution needed to truly determine the population density of pulsars at the center of galaxies.
“We look forward to seeing what follow-up studies will reveal about this pulsar candidate,” Perez said. “If confirmed, it could help us better understand both our galaxy and general relativity as a whole.”
Team results were posted on February 9th. Journal of Astrophysics.