(ORDO NEWS) — Dark matter is one of the greatest mysteries of the universe. And although a large number of studies have been carried out to date, from which evidence of the existence of this mysterious substance indirectly follows, its invisible nature complicates detection, so the structure of dark matter remains unknown to scientists.
Dark matter may consist of fundamental and exotic particles that have not yet been discovered. An alternative hypothesis suggests that it is made up of many massive, compact objects such as primordial black holes (that is, black holes that formed in the early universe).
In a new study, scientists at the Tata Institute for Basic Research, India, led by S. Basak, have placed further limits on the fraction of dark matter that is made up of compact objects based on an analysis of gravitational microlensing phenomena.
According to Einstein’s General Theory of Relativity, massive cosmic objects act on the light passing by them like a lens.
They can have a similar lensing effect on gravitational waves emitted in the distant part of the Universe, so in their study Basak and his team analyzed the influence of hypothetical primordial black holes that form dark matter on the propagation of gravitational waves, the signals of which are received by the LIGO and Virgo detectors.
As a result of the analysis, Basak and his colleagues did not find distortions of gravitational wave signals as a result of microlensing, so the data obtained allowed us to impose additional restrictions on the fraction of “compact dark matter”, that is, dark matter consisting of massive black holes.
According to the authors, the limitations they have obtained are quite moderate. From them it follows only that no more than 50 percent of dark matter can be represented by massive black holes, which, in general, is not new information.
However, in the next few years, the LIGO and Virgo observatories are expected to observe hundreds and thousands of gravitational wave events, which will significantly refine the obtained limitations.
In the future, the authors plan to analyze new gravitational wave signals registered with the LIGO-Virgo detectors. In addition, they hope that their data will inspire other research teams to use gravitational wave microlensing to study the nature of dark matter.
Contact us: [email protected]