Video courtesy of NASA
In an effort to understand how black holes shape the evolution of galaxies, astronomers spent eight months creating a series of time-lapse movies from 400 observations made by NASA’s Hubble Space Telescope. The movies, taken from observations conducted over a 13-year period from 1995-2008, show a 5,000-mile-long jet of superheated gas being ejected from a supermassive black hole at the center of a giant galaxy known as M87. The galaxy is located some 50 million light-years away, at the center of the Virgo cluster of roughly 2,000 galaxies, and the supermassive black hole at M87’s center is several billion times more massive than our Sun. “Central, supermassive black holes are a key component in all big galaxies,” said Eileen T. Meyer of the Space Telescope Science Institute in Baltimore, Md. “Most of these black holes are believed to have gone through an active phase, and black-hole powered jets from this active phase play a key role in the evolution of galaxies. By studying the details of this process in the nearest galaxy with an optical jet, we can hope to learn more about galaxy formation and black hole physics in general.”
The spiraling jet of plasma being ejected from M87’s central black hole is only visible because it travels so fast, and Meyer has found evidence suggesting a helix-shaped magnetic field surrounding the black hole is the cause of the jet’s spiral motion. Several gas clumps appear to zigzag as if moving along a spiral path in the jet, while other gas clumps appear to loop around a structure which is invisible in Hubble’s observations. M87’s jet of superheated gas is composed of a long string of gas blobs which brighten and dim over time, and the Hubble data is shedding light as to why.
“The jet structure is very clumpy. Is this a ballistic effect, like cannonballs fired sequentially from a canon,” Meyer asked, “or are there some particularly interesting physics going on, such as a shock that is magnetically driven?”
Meyer and her research team have found evidence in the Hubble observations to support both scenarios.
“We found things that move quickly,” Meyer said. “We found things that move slowly. And, we found things that are stationary. This study shows us that the clumps are very dynamic sources.” Meyer intends on using Hubble to study at least three more jets, as it is too soon to conclude whether or not all black-hole-powered jets behave in the same manner as the one emitting from M87’s black hole. “It’s always dangerous to have exactly one example because it could be a strange outlier,” Meyer said. “The M87 black hole is justification for looking at more jets.”