Could black holes still be a myth after the appearance of gravitational waves?
Scientists hope that future gravitational wave detections will allow them to directly observe mysterious black holes.
Gravitational wave detectors have found direct evidence of black holes as massive as giants, while the Event Horizon telescope has found an image of a supermassive black hole hundreds of millions of times the mass of the sun.
But the intermediate-mass black holes in the middle, known as IMBHs, are about 100 to 100,000 times the mass of the sun and have yet to be directly observed. According to a paper published in Nature Astronomy, the researchers found that their new mathematical work could pave the way for future research using gravitational wave detectors to detect black holes.
The Triple Gravitational wave detectors on Earth -- the U.S. Two LASER Interferometer Gravitational-Wave Observatory (LIGO) and the Italian Virgo detector -- have detected ripples in space-time, known as gravitational waves, that occur when black holes orbit and merge. The largest black hole ever observed is 80 times the mass of the sun. But a massive black hole would produce a low frequency that is currently audible to the detector. Intermediate-mass black holes may be among the stars, also known as globular clusters, or harbingers of even larger black holes in our galaxy. It's hard to say!
"I've been studying black holes for quite a long time, and when I started, it seemed more like a myth."
The researchers, led by Karan Jani of Vanderbilt, described how pairs of intermediate-mass black holes could be found using an upcoming combination of gravitational waves experiments. The future gravitational wave observatory in space, LISA, will be able to observe black holes coalesce at the lowest possible frequencies. The loudest part of the probe is the fusion itself, which will be shown in more sensitive ground tests. In an effort to sharpen observations from Earth, scientists are working on improving the Voyager Optical Interferometer Gravitational Wave Observatory, or LIGO, and two new detectors, the European Einstein Telescope and the Cosmic Explorer in the Quake-free Zone in the United States.
The team compared different combinations of black hole mass and distance to see them experimentally and see what the signal looks like. For pairs of intermediate-mass black holes 1,000 to 3,000 times the mass of the sun, LISA plus the Einstein telescope might be able to see such mergers occurring billions of light-years away (for heavier combinations, where the black hole is larger than another black hole, the shorter the distance). According to the paper, the most sensitive instrument combination may be the LISA and Einstein Telescopes, even though LISA and Voyager are still leading the hunt for medium-sized black holes less than 2,000 times the mass of the sun.
In other words, if intermediate black holes exist and they merge, the recommended gravitational wave experiments should be able to find them. The paper suggests what their signals might look like. In addition, there is already direct evidence for intermediate-mass black holes, in the form of radio waves called co-0.40-0.22 matter.
This is exciting research. "This paper is unique in that first I saw different ways of calculating IMBI waveforms. In general our team knew that LISA and Voyager could detect such binaries, but the paper did the detailed calculations and provided formulas. Jillian Bellovary, an assistant professor of black hole research at Queens Community College in New York, told Gizmodo in an email. "These calculations will help our team interpret signals from gravitational wave detectors; The more waveform calculations we have, the better we can understand what the detectors are telling us."
But this work is mostly data-driven, and we still don't know how common moderate-mass black holes are in the universe. "They probably won't happen during the LISA mission period (four to 10 years), if IMBHs are really rare," Belovari says. "There's no way to know until the detectors are always online." In practice, this will require funding and the establishment of new or upgraded trials.
But one thing is clear: physicists have only scratched the surface of the science of the observed black hole, and there is an entire zoo of objects yet to be discovered.
"I already research into black holes for quite some time, when I began to study, for people compared to the reality they're more like a myth," di del shoemaker, the study authors and Georgia institute of technology professor of physics, told astronomical online by telephone. "now they are everywhere, interestingly can see all the different forms of black holes in the universe.