A leading gravitational wave observatory recently detected ripples in space-time that scientists say come from the collision of the ultra-dense remnants of dead stars and unknown objects.
Stellar remnants are so-called neutron stars. This is what’s left when a massive star collapses, leaving only a dense core. Neutron stars are among the densest objects in the universe and have a strong gravitational field, but not as strong as a black hole, whose gravity is so strong that not even light can escape its event horizon.
These two masters of the universe dance and clash across the universe; first confirmed neutron star-black hole merger observed Made in 2021. Their interaction produces gravitational waves, the stretching and squeezing of spacetime, which can be detected by observatories such as the LIGO-Virgo-KAGRA collaboration, which is at the heart of the latest research.
LIGO-Virgo-KAGRA detected gravitational wave signals in May 2023, just Observatory resumes operations Some upgrades have reduced the amount of noise in the detector and increased its sensitivity to subtle perturbations in space and time.
This unique gravitational wave signal traveled 650 million light-years to the LIGO Livingston Observatory in Louisiana. The researchers determined that the signal came from the merger of two objects. One of the objects has a mass of 1.2 to 2 times the mass of the Sun, and the other has a mass of about 2.5 to 4.5 times the mass of the Sun. The signal is called GW230529_181500, or GW230529 for short.
Astrophysicists concluded that the smaller object was probably a neutron star. But the larger object is heavier than any known neutron star, suggesting it may be a very small black hole.Their paper describing the signal and its possible source is Currently hosting on the LIGO website.
This unknown object occupies the apparent mass gap that exists between the heaviest known neutron stars and the lightest black holes. Further examination of the collision will indicate whether the unknown object was a low-mass black hole, as the team suspected, or something else.
Jess McIver, an astronomer at the University of British Columbia and deputy spokesperson for the LIGO Science Collaboration, said the detection “suggests that the probability of similar collisions between neutron stars and low-mass black holes may be higher than we previously thought.”in a collaboration release.
The press release noted that of the nearly 200 measurements of the masses of compact objects, only one other merger involved an object in an apparent mass gap, namely with a black hole. (For gravitational wave connoisseurs, the signal is GW190814.) But the recent observation is the first between a mass-gap object and a neutron star.
The fourth observation run of LIGO-Virgo-KAGRA will restart on April 10 and will continue without planned interruption until February 2025, when the collaboration expects to observe more than 200 gravitational wave signals.
It’s been a productive few years for gravitational wave science, with more exciting things to come.Last year, some pulsar timing consortium First sign of gravitational wave background independently confirmed— a constant cacophony of gravitational waves throughout the universe that they believe come from the dance of supermassive black hole binaries.
Earlier this year, ESA officially adopts LISA plan, a space-based gravitational wave observatory. LISA will consist of three spacecraft rotating in space in a triangular formation. LISA will listen for gravitational waves without producing any of the noise seen on Earth that could disrupt data collected by LIGO-Virgo-KAGRA.
The team still needs to screen 80 important candidate signals. Therefore, the day of observing the gravitational universe is coming.
more: These violent collisions could create dark matter