Astronomers Create Black-Hole “GPS” Based on One of the Most Massive in the Universe


A team of Japanese astrophysicists and space scientists have found a way to more precisely describe where in space a very large, but distant black hole lies. In their paper published in Nature, the team describes how they’ve used data from a large array of radio telescopes spread across the Pacific ocean to measure high energy emissions that are ejected from areas inside the galaxy M87 due to the actions of the massive black hole that lies somewhere near its center.

While it is commonly known that black holes generally suck up everything around them, there is one exception; jets of radio waves that are thought to form when material that is being sucked in spirals, forming a cone that ejects material as it spins. Sort of like a tornado that sucks up material then spits it out into the air. Only in this case, the jets are all perpendicular to the source. It’s because of these radio jet emissions that we here on Earth are able to find black holes. And though the process by which the jets form is still rather a mystery, scientists are getting closer, and that’s where this new research comes in.

To get a better picture of where the radio waves are actually emanating from inside of M87 relative to the black hole at its center, the team traced the radio jets (using data from the Very Long Baseline Array of radio satellites in the Pacific and complex mathematical models) to near their origin, which then allowed them to better estimate where the black hole actually resides. To their surprise they found that the core of the radio jet appears to be closer to the black hole itself (a fraction of a light year) than had been previously thought.

As with any advance in understanding the cosmos, the results of this latest research while providing new information on how galaxies and black holes work, they also whet the appetite for more. Newer and better radio telescopes still in the planning stages will hopefully give more detail about matter as it is being pulled into a black hole, giving new clues about what is emitted in the process.

Powerful radio jets from active galactic nuclei are thought to be powered by the accretion of material onto the supermassive black hole (the ‘central engine’). Elliptical galaxy M87 in the Virgo Cluster, shown at top of page, is one of the closest examples of this phenomenon. The features in this image imply that outbursts and deep sounds have been generated by the black hole for eons.

The black hole located in the center of M87 is one of the most massive in the universe. The huge reservoir of hot gas in this cluster is shown in this low energy X-ray image from the Chandra X-ray Observatory (red). An optical image from the Digitized Sky Survey shows stars in M87 in blue.

A series of unevenly spaced loops and bubbles are visible in the hot gas below and to the left of the center of M87. These features are produced by small outbursts from close to the black hole about once every 6 million years. The sound waves generated by these outbursts, not visible in this image, will be incredibly deep, about 56 octaves below middle C. Because the outbursts are unevenly spaced the sound will be more like noise from the black hole rather than a harmonious musical performance.

A shock wave — similar to a sonic boom — is detected in a separate Chandra image of M87 that shows high energy X-rays. This shock was produced by a powerful outburst from the black hole about 20 million years ago. The properties of the shock, including the change in temperature and density in the gas, are consistent with classical physics. A large bubble in the X-ray gas shows another powerful outburst occurred about 50 million years earlier. The long interval between these two outbursts provides evidence for even deeper sounds, 58 or 59 octaves below middle C.

Other remarkable features are seen in M87 for the first time including narrow filaments of X-ray emission, which may be due to hot gas trapped to magnetic fields. One of these filaments is over 100,000 light years long, and extends below and to the right of the center of M87 in almost a straight line.

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