Disks, Spikes, and Clouds: A Backyard Peek of a Black Hole

Advertisements

This article was reviewed based on Science X’s editorial process and policies. The editors have highlighted the following attributes ensuring the credibility of the content:

Advertisements

verified

peer-reviewed publication

trusted source

Advertisements

correct

Advertisements






Artist’s impression of the LISA space experiment detecting a gravitational wave. With such future measurements, it will be possible to get a peek into a black hole’s backyard. Credit: NASA

The first direct detection of gravitational waves in 2015 opened a new window on the universe, notably allowing for the observation of the merger of pairs of massive black holes. This young field of research has matured very quickly and by now dozens of black hole mergers have been observed.

Current observations are limited to the final stages of the collapse, often for only a few seconds, when the emitted gravitational waves are extremely strong. Fortunately, several new experiments are underway that will allow researchers to observe black hole pairs for much longer before the merger occurs, potentially even for years.

Advertisements

When these much more precise measurements start arriving, researchers want to be ready and able to interpret them. Pippa Cole, postdoctoral researcher in Gianfranco Bertone’s group, and first author of a new article published in Nature astronomyhe explains, ‘With current measurements, we can learn some facts about merging black holes themselves, but very little about the environment in which the merger occurs. That environment itself is extremely interesting. For example, it can teach us one of the other Current mysteries in astrophysics: that of dark matter. Once we can use an upcoming detector like LISA to observe merging black holes for much longer, it will be possible to make meaningful statements about their environment.”

Black hole environments

There are at least three different kinds of interesting environments that could surround black holes. The best known is a so-called accretion disk of very hot gas swirling around the black hole, like the ones recently imaged by the Event Horizon Telescope. But there are other possibilities.

A black hole might be surrounded by a cloud of ultralight particles, forming a structure that astronomers have dubbed the gravitational atom. And finally, there may be dark matter, an elusive form of matter that appears to permeate the cosmos at all scales, but whose fundamental nature remains unknown. It is expected to accumulate around black holes as they form and grow, in high-density configurations called peaks.

Advertisements

Cole says, “The nice thing is that with the new observations it will become possible to distinguish between all three situations, as well as distinguish them from the case where the black hole’s back yard is just empty, where the two black holes are spiraling around.” around one another in a vacuum. We have succeeded in developing statistical techniques which, given enough data and a large enough mass difference between the two black holes, should be able to distinguish very clearly between all four scenarios.”

According to Cole and collaborators, the next generation of experiments will be able to identify gravitational waves generated by black hole mergers in the presence of an environment, be it an accretion disk, a gravitational atom or a peak of dark matter. This opens up the possibility of searching for new ultralight particles, as well as dark matter candidates, with gravitational waves.

Bertone says: “These are exciting times. We will soon enter a new era of physics and astronomy. Just as precision particle physics allows us to seek new physics in particle accelerators on Earth, gravitational wave precision will soon allow us to search for dark matter and new particles in the universe.”

Advertisements

More information:
Philippa S. Cole et al, Distinctive Environmental Effects on Binary Black Hole Gravitational Waveforms, Nature astronomy (2023). DOI: 10.1038/s41550-023-01990-2

About the magazine:
Nature astronomy

Advertisements

Advertisements

#Disks #Spikes #Clouds #Backyard #Peek #Black #Hole

Leave a Comment