New image of black hole opens door to deeper space understanding

By Dean Murray via SWNS

A new image of supermassive black hole M87* is the most detailed yet.

The Event Horizon Telescope (EHT) Collaboration has released new images of the object at the center of the galaxy Messier 87, using data from observations taken in April 2018.

It appears to show how the bright black hole shadow has shifted since first sighting in 2017, due to the turbulent nature of black holes.

A black hole is a region in space where the gravitational pull is so strong that nothing, not even light, can escape from it.

EHT says that the participation of the newly commissioned Greenland Telescope, and a dramatically improved recording rate across the array, mean the 2018 observations offer a view of the source independent from the first in 2017.

M87*, described by EHT as "the beating heart of the giant elliptical galaxy Messier 87", is 55 million light years away from Earth.

A recent paper published in the journal Astronomy & Astrophysics presented new images from the 2018 data that reveal a familiar bright ring the same size as the one observed in 2017.

EHT explains: "This bright ring surrounds a deep central depression, “the shadow of the black hole,” as predicted by general relativity.

"Excitingly, the brightness peak of the ring has shifted by about 30º compared to the images from 2017, which is consistent with our theoretical understanding of variability from turbulent material around black holes."

Keiichi Asada, an associate research fellow at Academia Sinica Institute for Astronomy and Astrophysics in Taiwan, says: "A fundamental requirement of science is to be able to reproduce results.

"Confirmation of the ring in a completely new data set is a huge milestone for our collaboration and a strong indication that we are looking at a black hole shadow and the material orbiting around it."

In 2017, the EHT took the first image of a black hole. The image of the black hole revealed a bright circular ring, brighter in the southern part of the ring. Further analysis of the data also revealed the structure of M87* in polarised light, giving greater insight into the geometry of the magnetic field and the nature of the plasma around the black hole.

“One of the remarkable properties of a black hole is that its radius is strongly dependent on only one quantity: its mass,” said Dr. Nitika Yadlapalli Yurk, a former graduate student at the California Institute of Technology (Caltech), now a postdoctoral fellow at the Jet Propulsion Laboratory in California. “Since M87* is not accreting material (which would increase its mass) at a rapid rate, general relativity tells us that its radius will remain fairly unchanged over human history. It’s pretty exciting to see that our data confirm this prediction.”

EHT say: "While the size of the black hole shadow did not change between 2017 and 2018, the location of the brightest region around the ring did change significantly. The bright region rotated about 30º counterclockwise to settle in the bottom right part of the ring at about the 5 o’clock position.

"While the 2018 EHT array still cannot observe the jet emerging from M87*, the black hole spin axis predicted from the location of the brightest region around the ring is more consistent with the jet axis seen at other wavelengths.

“The biggest change, that the brightness peak shifted around the ring, is actually something we predicted when we published the first results in 2019,” said Dr. Britt Jeter, a postdoctoral fellow at Academia Sinica Institute for Astronomy and Astrophysics in Taiwan. “While general relativity says the ring size should stay pretty fixed, the emission from the turbulent, messy accretion disk around the black hole will cause the brightest part of the ring to wobble around a common center. The amount of wobble we see over time is something we can use to test our theories for the magnetic field and plasma environment around the black hole.”