Tag Archives: mergers

Astrophysicists Identify Gravitational Waves from the Largest Black Hole Mergers Recorded to Date

Posted on by
Reply

The twin detectors of the NSF’s Laser Interferometer Gravitational-Wave Observatory (LIGO) have made a groundbreaking discovery by detecting the highest composite mass recorded to date and the merger of two black holes. This event, identified as GW231123 and discovered on November 23, 2023, produced a final black hole with a mass over 225 times that of the Sun.

GW231123 An infographic detailing the merger of black holes. Image credits: Simona J. Miller/Caltech.

LIGO made history in 2015 with the first direct detection of gravitational waves, the ripples in spacetime.

In that instance, the waves were generated by the merger of black holes, culminating in a black hole with a mass 62 times that of our Sun.

The signal was simultaneously detected by LIGO’s twin detectors located in Livingston, Louisiana, and Hanford, Washington.

Since then, the LIGO team has collaborated with partners from Italy’s Virgo detectors and Japan’s KAGRA to create the LVK collaboration.

These detectors have collectively observed over 200 black hole mergers during their fourth observational run since starting in 2015.

Previously, the largest black hole merger recorded was in 2021 during the event GW190521, which had a total mass of 140 times that of the Sun.

During the GW231123 event, a black hole with a mass of 225 was formed by merging two black holes, one approximately 100 times and the other 140 times the mass of the Sun.

This discovery places it in a rare category known as intermediate mass black holes, which are heavier than those resulting from star collapses but significantly lighter than the supermassive black holes found at the centers of galaxies.

In addition to their substantial mass, these merged black holes exhibited rapid rotation.

“This is the largest black hole binary we’ve observed in gravitational waves and poses a significant challenge to our understanding of black hole formation,” stated Dr. Mark Hannam, an astrophysicist at Cardiff University and a member of the LVK collaboration.

“The existence of such a large black hole defies standard stellar evolution models.”

“One potential explanation is that the two black holes in this binary could have formed from the merger of smaller black holes.”

“This observation highlights how gravitational waves uniquely uncover the fundamental and exotic properties of black holes throughout the universe,” remarked Dr. Dave Reitze, executive director of LIGO at Caltech.

Researchers announced this week the discovery of GW231123, which will be discussed at the 24th International Conference on General Relativity and Gravity (GR24) and the 16th Edoardo Amaldi Meeting on Gravitational Waves, held jointly at the Gr-Amaldi Meeting in Glasgow, Scotland.

____

LIGO-Virgo-KAGRA Collaboration. GW231123: The largest black hole binary detected by gravitational waves. Gr-Amaldi 2025

Source: www.sci.news

Physicists suggest that ultra-high energy cosmic rays originate from neutron star mergers

Posted on by
Reply

Ultra-high energy cosmic rays are the highest energy particles in the universe, and their energy is more than one million times greater than what humans can achieve.

Professor Farrar proposes that the merger of binary neutron stars is the source of all or most ultra-high energy cosmic rays. This scenario can explain the unprecedented, mysterious range of ultra-high energy cosmic rays, as the jets of binary neutron star mergers are generated by gravity-driven dynamos and therefore are roughly the same due to the narrow range of binary neutron star masses. Image credit: Osaka Metropolitan University / L-Insight, Kyoto University / Riunosuke Takeshige.

The existence of ultra-high energy cosmic rays has been known for nearly 60 years, but astrophysicists have not been able to formulate a satisfactory explanation of the origins that explain all observations to date.

A new theory introduced by Glennnies Farrer at New York University provides a viable and testable explanation of how ultra-high energy cosmic rays are created.

“After 60 years of effort, it is possible that the origins of the mysterious highest energy particles in the universe have finally been identified,” Professor Farrar said.

“This insight provides a new tool to understand the most intense events in the universe. The two neutron stars fuse to form a black hole. This is the process responsible for creating many valuable or exotic elements, including gold, platinum, uranium, iodine, and Zenon.”

Professor Farrer proposes that ultra-high energy cosmic rays are accelerated by the turbulent magnetic runoff of the dual neutron star merger, which was ejected from the remnants of the merger, before the final black hole formation.

This process simultaneously generates powerful gravitational waves. Some have already been detected by scientists from the Ligo-Virgo collaboration.

“For the first time, this work explains two of the most mystical features of ultra-high energy cosmic rays: the harsh correlation between energy and charge, and the extraordinary energy of just a handful of very high energy events,” Professor Farrar said.

“The results of this study are two results that can provide experimental validation in future work.

(i) Very high energy cosmic rays occur as rare “R process” elements such as Xenon and Tellurium, motivating the search for such components of ultra-high energy cosmic ray data.

(ii) Very high-energy neutrinos derived from ultra-high-energy cosmic ray collisions are necessarily accompanied by gravitational waves generated by the merger of proneutron stars. ”

study It will be displayed in the journal Physical Review Letter.

____

Glennys R. Farrar. 2025. Merger of dichotomous neutron stars as the source of the finest energy cosmic rays. Phys. Pastor Rett 134, 081003; doi:10.1103/physrevlett.134.081003

Source: www.sci.news

Thermal secrets uncovered in neutron star mergers through gravitational waves

Posted on by
Reply

by US Department of Energy
December 14, 2023

Scientists used supercomputer simulations to study gravitational waves produced by neutron star mergers and found a correlation between residual temperature and gravitational wave frequency. These findings are important for future gravitational wave detectors that distinguish models of hot nuclear material. Credit: SciTechDaily.com

Binary simulation neutron star This merger suggests that future detectors will distinguish between different models of hot nuclear material.

Researchers used supercomputer simulations to investigate the effects of neutron star mergers gravitational waves, found a significant relationship with debris temperature. This research will aid future advances in the detection and understanding of hot nuclear materials.

Exploring neutron star mergers and gravitational waves

When two neutron stars orbit each other, they emit ripples into spacetime called gravitational waves. These ripples drain energy from the orbit until the two stars eventually collide and combine into one object. Scientists used supercomputer simulations to investigate how the behavior of different models of nuclear material affects the gravitational waves released after these mergers. They found a strong correlation between the temperature of the debris and the frequency of these gravitational waves. Next generation detectors will be able to distinguish these models from each other.

Plot comparing density (right) and temperature (left) for two different simulations (top and bottom) of a neutron star merger, viewed from above, approximately 5 ms after the merger.Credit: Jacob Fields, Pennsylvania State University

Neutron Star: Institute for Nuclear Materials

Scientists use neutron stars as laboratories for nuclear materials under conditions that would be impossible to explore on Earth. They will use current gravitational wave detectors to observe neutron star mergers and learn how cold, ultra-dense matter behaves. However, these detectors cannot measure the signal after the stars have merged. This signal contains information about hot nuclear material. Future detectors will be even more sensitive to these signals. Because different models can also be distinguished from each other, the findings suggest that future detectors could help scientists create better models of hot nuclear material.

Detailed analysis of neutron star mergers

The study investigated neutron star mergers using THC_M1, a computer code that simulates neutron star mergers and accounts for the bending of spacetime due to the star’s strong gravitational field and neutrino processes in dense matter. . The researchers tested the effect of heat on mergers by varying the specific heat capacity of the equation of state, which measures the amount of energy required to raise the temperature of neutron star material by one degree Celsius. To ensure the robustness of their results, the researchers ran their simulations at two resolutions. They repeated the high-resolution run using a more approximate neutrino processing.

References:

“Thermal effects in binary neutron star mergers” by Jacob Fields, Aviral Prakash, Matteo Breschi, David Radice, Sebastiano Bernuzzi, and Andre da Silva Schneider, July 31, 2023. of Astrophysics Journal Letter.
DOI: 10.3847/2041-8213/ace5b2

“Identification of nuclear effects in neutrino-carbon interactions in low 3 momentum transfer” until February 17, 2016 physical review letter.
DOI: 10.1103/PhysRevLett.116.071802

Funding: This research was primarily funded by the Department of Energy, Office of Science, Nuclear Physics Program. Additional funding was provided by the National Science Foundation and the European Union.

This research used computational resources available through the National Energy Research Scientific Computing Center, the Pittsburgh Supercomputing Center, and the Pennsylvania State University Computing and Data Science Institute.

Source: scitechdaily.com