New research suggests an innovative method for analyzing ganse star systems in the universe

In a recently published study, a team of researchers led by ARC Center Excel for Excellence for Gravitational Wave Discovery (Oz Zagraw) at Monash University suggests an innovative method for analyzing gravitational waves from neutron star mergers, where two Collective), depending on how fast they rotate.

Neutron stars are very gaense stellar objects that form when massive stars explode and die, explode, their cores fall off, and protons and electrons melt into each other to form a residual neutron star.

In 2017, the merger of two neutron stars, known as GW 170817, was first observed by LIGO and Virgo gravity-wave detectors. This merger is known because scientists were also able to see the light produced by it: high-energy gamma rays, visible light, and microwaves. Since then, an average of three scientific studies have been published daily on GW170817.

In January this year, LIGO and Virgo associates announced another neutron star merger event called GW 190425. Although no light was found, this event is particularly interesting because the two merged neutron stars are significantly heavier than GW170817, as well as the previously known double neutron stars in the galaxy.

Scientists use gravitational-wave signals – waves in the fabric of space and time – to find pairs of neutron stars and measure their masses. A pair of heavy neutron stars is called a ‘primary’; Lighter is a ‘secondary’.

Recycle-Slow Labeling Scheme of Binary Neutron Star System

The binary neutron constellation system usually begins with two common stars, each ten to twenty times larger than the Sun. When these giant stars are old and run out of ‘fuel’, their life ends in supernova explosions that leave behind compact fossils or neutron stars. Each fossil neutron star weighs about 1.4 times the mass of the Sun, but is only 25 kilometers in diameter.

The first-born neutron star usually undergoes a ‘recycling’ process: it collects matter from its attached star and begins spinning rapidly. The second born neutron star does not accumulate matter; Its spin speed also slows down quickly. At that point, it is estimated that the two neutron stars merge millions of years later. Recycle The neutron star is still spinning fast, while another non-recycled neutron star may be spinning Slowly Slowly.

Ga way is another way to form a binary neutron star system through constantly changing interactions in star clusters. In this scenario, two unrelated neutron stars, on their own or in other separate star systems, meet, join, and eventually merge like a happy couple due to their gravitational waves. However, current modeling of stellar clusters suggests that this view is ineffective in merging neutron stars.

Xingjiang Xu, a researcher and lead author of the study, says: ‘The motivation to propose a recycle-slow labeling scheme for binary neutron star systems is twofold. First, it is the expected general feature for a neutron star merger. Second, labeling two neutron stars as primary and secondary may be insufficient because they have the potential of the same people and it is difficult to say which is the most difficult. ”

The recent Ozgrave study takes a new look at both GW170817 and GW190425 by adopting a recycle-slow scheme. It has been found that the recycled neutron star in GW170817 rotates only slightly or even slowly, while the GW190425 is spinning rapidly, probably once every 15 milliseconds. It was also found that both merger events are likely to have about two identical equal neutron stars. With little or no evidence of spin in GW170817, and neutron stars spin over time, researchers determined that the binary may have taken billions of years to merge. This agrees well with the observations of its host Galaxy, called NGC 4993, where little star formation activity has been observed over the last billions of years.

Ozgrav’s associate investigator and collaborator Gregory Ashton says: “Our proposed astrophysical structure will allow us to answer important questions about the universe, such as the formation of binary neutron stars with different supernova explosion patterns? Do clusters contribute to the creation? ”

LIGO / Virgin Detectors completed their Joint Third Observation Run (O3) earlier this year and is currently carrying out scheduled maintenance and improvements. When the fourth run (O4) begins in 2021, scientists will easily expect further discovery of the neutron star merger. The prospects will be even brighter in the coming years when Japanese underground detectors KAGRA and LIGO-India detectors join the global network.

“We are in the golden age of studying binary neutron stars with highly sensitive gravity-wave detectors, which will lead to dozens of discoveries over the next few years,” Xu added.