A group of international scientists led by the Galician Institute for High Energy Physics (IGFAE) and the ARC Center of Excellence for the Discovery of Gravitational Waves (OzGrav) have proposed a new way to determine the expansion rate of the universe with an error of 2%.
In a recently published article, a group of scientists proposed a simple and new method to reduce the measurement accuracy of the Hubble constant to 2% using data on a pair of merging neutron stars.
According to Professor Calderon Bustillo, it is difficult to interpret how far these mergers are going. Therefore, the team proposed to study the secondary, much weaker components of the gravitational wave signals emitted by mergers of neutron stars, known as higher modes.
This works well in the case of black hole mergers, since modern detectors can register this moment up to high modes. But in the case of neutron stars, the height of the merger signal is so high that detectors cannot detect it.
In their study, the team performed computer simulations of a merger of neutron stars. By studying these models, the team determined that a detector like NEMO could measure the Hubble constant with an accuracy of 2%.
One of the most striking implications of this study is that it can determine whether the universe is expanding uniformly in space, as currently assumed.