Nav: Home

Eyeballing a black hole's mass

September 24, 2019

There are no scales for weighing black holes. Yet astrophysicists from the Moscow Institute of Physics and Technology have devised a new way for indirectly measuring the mass of a black hole, while also confirming its existence. They tested the new method, reported in the Monthly Notices of the Royal Astronomical Society, on the Messier 87 active galaxy.

Active galactic nuclei are among the brightest and most mysterious objects in space. A galaxy is deemed active if it produces a thin long beam of matter and energy directed outward. Known as a relativistic jet, this phenomenon cannot be accounted for by the stars in the galaxy. The current consensus is that the jets are produced by some kind of "motors," termed galactic nuclei. While their nature is poorly understood, researchers believe that a spinning black hole could power an active galaxy.

Messier 87 in the Virgo constellation is an active galaxy that is closest to Earth, and also the one best studied. It has been observed on a regular basis since 1781, when it was first discovered as a nebula. It took some time before astronomers realized that it was a galaxy, and its optical jet -- discovered in 1918 -- was the first one ever to be observed.

The structure of the Messier 87 jet has been meticulously studied, with its plasma jet velocities mapped and the temperature and particle number density near the jet measured. The jet's boundary has been studied in such fine detail that researchers discovered it was inhomogeneous along its length, changing its shape from parabolic to conical. Originally discovered as an isolated case, this effect was later confirmed for a dozen other galaxies, though M87 remains the clearest example of the phenomenon.

The sheer bulk of observations allow for testing hypotheses regarding the structure of active galaxies, including the relation between the jet shape break and the black hole's gravitational influence. Jet behavior and the existence of the supermassive black hole are two sides of the same coin: The former can be explained in terms of the latter while theoretical models of black holes are tested via jet observations.

Astrophysicists exploited the fact that the jet boundary is made up of segments of two distinct curves and used the distance between the core and the break of the jet, together with the jet's width, to indirectly measure the black hole mass and spin. To that end, MIPT scientists developed a method that combines a theoretical model, computer calculations, and telescope observations.

The researchers are trying to describe the jet as a flow of magnetized fluid. In this case, the shape of the jet is determined by the electromagnetic field in it, which in turn depends on various factors, such as the speed and charge of jet particles, the electric current within the jet, and the rate at which the black hole accretes matter. A complex interplay between these characteristics and physical phenomena gives rise to the observed break.

There is a theoretical model that predicts the break, so the team could determine which black hole mass results in the model reproducing the observed shape of the jet. This provided a new model for black hole mass estimation, a new measurement method, and a confirmation of the hypotheses underlying the theoretical model.

"The new independent method for estimation of black hole mass and spin is the key result of our work. Even though its accuracy is comparable to that of the existing methods, it has an advantage in that it brings us closer to the end goal. Namely, refining the parameters of the core 'motor' to deeper understand its nature," said Elena Nokhrina, the lead author of the paper and deputy head of the MIPT laboratory involved in the study.
-end-
The Laboratory of Fundamental and Applied Research of Relativistic Objects of the Universe studies quasar jets, binary black holes and other tight binary systems, as well as the magnetosphere structure of pulsars, accretion disks, and jets from young stars. In addition to offering insights into the processes occurring in our galaxy and the universe at large, this research has a practical dimension: It improves the precision of our navigation systems, which use distant quasars as reference points. The head of the laboratory is Yuri Kovalev, a corresponding member of the Russian Academy of Sciences (RAS).

Scientists from the Moscow Institute of Physics and Technology were joined in this research by their colleagues from Lebedev Physical Institute, RAS; Delft University of Technology and the Joint Institute for VLBI ERIC, the Netherlands; the Institute of Astronomy and Astrophysics, Taiwan; the National Astronomical Observatory of Japan and the Graduate University for Advanced Studies, Japan.

Moscow Institute of Physics and Technology

Related Black Hole Articles:

Black hole team discovers path to razor-sharp black hole images
A team of researchers have published new calculations that predict a striking and intricate substructure within black hole images from extreme gravitational light bending.
Planets around a black hole?
Theoreticians in two different fields defied the common knowledge that planets orbit stars like the Sun.
Black hole mergers: Cooking with gas
Gravitational wave detectors are finding black hole mergers in the universe at the rate of one per week.
Going against the flow around a supermassive black hole
At the center of a galaxy called NGC 1068, a supermassive black hole hides within a thick doughnut-shaped cloud of dust and gas.
Eyeballing a black hole's mass
There are no scales for weighing black holes. Yet astrophysicists from the Moscow Institute of Physics and Technology have devised a new way for indirectly measuring the mass of a black hole, while also confirming its existence.
First 'overtones' heard in the ringing of a black hole
By listening for specific tones in the gravitational waves of black hole mergers, researchers are putting Albert Einstein's theories to new tests.
Black hole holograms
Japanese researchers show how a holographic tabletop experiment can be used to simulate the physics of a black hole.
Where in the universe can you find a black hole nursery?
Gravitational wave researchers at the University of Birmingham have developed a new model that could help astronomers track down the origin of heavy black hole systems in the universe.
Astronomers capture first image of a black hole
The Event Horizon Telescope (EHT) -- a planet-scale array of eight ground-based radio telescopes forged through international collaboration -- was designed to capture images of a black hole.
Hiding black hole found
Astronomers have detected a stealthy black hole from its effects on an interstellar gas cloud.
More Black Hole News and Black Hole Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Teaching For Better Humans 2.0
More than test scores or good grades–what do kids need for the future? This hour, TED speakers explore how to help children grow into better humans, both during and after this time of crisis. Guests include educators Richard Culatta and Liz Kleinrock, psychologist Thomas Curran, and writer Jacqueline Woodson.
Now Playing: Science for the People

#556 The Power of Friendship
It's 2020 and times are tough. Maybe some of us are learning about social distancing the hard way. Maybe we just are all a little anxious. No matter what, we could probably use a friend. But what is a friend, exactly? And why do we need them so much? This week host Bethany Brookshire speaks with Lydia Denworth, author of the new book "Friendship: The Evolution, Biology, and Extraordinary Power of Life's Fundamental Bond". This episode is hosted by Bethany Brookshire, science writer from Science News.
Now Playing: Radiolab

Space
One of the most consistent questions we get at the show is from parents who want to know which episodes are kid-friendly and which aren't. So today, we're releasing a separate feed, Radiolab for Kids. To kick it off, we're rerunning an all-time favorite episode: Space. In the 60's, space exploration was an American obsession. This hour, we chart the path from romance to increasing cynicism. We begin with Ann Druyan, widow of Carl Sagan, with a story about the Voyager expedition, true love, and a golden record that travels through space. And astrophysicist Neil de Grasse Tyson explains the Coepernican Principle, and just how insignificant we are. Support Radiolab today at Radiolab.org/donate.