by NASA scientists have discovered an amazing cosmic fossil created when a supermassive black hole erupted over 5 million years ago.
The team at the space agency’s Goddard Space Flight Center used the X-ray Multiple Mirror Mission (XMM-Newton) space telescope with help from NASA’s Chandra X-ray Observatory to measure the X-rays reflected by the cold gas clouds. see in the near area. spiral galaxy NGC 4945, 13 million light years away in the constellation Centaurus (the Centaur).
The gas appears to have ripped through the galaxy as it exploded around the central black hole, which has a mass equal to about 1.6 million suns and is currently feeding material around it, powering the bright galactic engine known as an active nucleus galactic (AGN). .
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This gas settled by this supermassive black hole is the raw material that falls out to create stars. Therefore, these results could help scientists to better understand the influence of supermassive black holes, which can be billions of times larger than the sun, on their environment and guide galactic evolution.
“There is an ongoing debate in the scientific community about how galaxies evolve. We find supermassive black holes at the center of almost all Milky Way galaxies, and an open question is how much of an impact they have compared to the effects of star formation,” Goddard astrophysicist and team leader Kimberly Weaver said in a statement. “By studying nearby galaxies like NGC 4945, which we think we’re seeing in the transition period, it helps us build better models of how stars and black holes produce galactic changes.”
Active star birth galaxy
Although most galaxies have a supermassive black hole at their core, not all of these cosmic titans are accreting matter, nor is their gravitational influence churning up the surrounding matter, creating the violent conditions required for AGN.
Galaxies like NGC 4945 that have AGNs, which can often outshine every star in the entire galaxy together, are called “active galaxies.” But sometimes the thick doughnut-shaped or “torus” dust at the center of these active galaxies is dense enough to obscure some of the light from the AGN from outside observers.
Light is not the only emission from the AGNs at the core of active galaxies, however; material that does not enter the black hole to be treated, or “accredited,” can be sent to the poles of the black hole with magnetic fields. From here, these particles are accelerated to speeds approaching the speed of light and are blasted out as jets that can stretch for thousands of light years. In addition, particles can escape from the AGNs in active galaxies through powerful winds of gas and dust.
A supermassive AGN powered by a black hole isn’t the only thing that separates NGC 4945 from other, more turbulent galaxies like the Milky Way. This nearby spiral galaxy is also classified as a “starburst galaxy”, indicating that it is undergoing an intense burst of star formation.
NGC 4945 is estimated to be forming stellar bodies at a rate of 18 solar-like stars per year, three times faster than the Milky Way’s star formation rate. This star birth is mainly concentrated in the heart of the galaxy and will only end when the raw material of star birth, cool and dense gas clouds, has been exhausted. This process is expected to take between 10 million and 100 million years.
Spotting a lost cosmic fossil in NGC 4945
Looking at NGC 4945 with the European Space Agency (ESA) XMM-Newton telescope, Weaver and team saw a feature called the iron K-alpha line, which occurs when high-energy X-rays light from the material around the disk supermassive central black hole on. it hits cold gas elsewhere in the galaxy.
The iron line is commonly seen in galaxies with AGN, but this observation surprised the team because it was not as close to the central black hole as expected, and as current theories suggest it should be.
Because NGC 4945 is seen at the edge of Earth from Earth’s view, NASA scientists were able to trace the iron line out 32,000 light-years across the galactic plane and 16,000 years across the inclined galaxy.
“Chandra has mapped K-alpha iron in other galaxies. In this one, it helped us study individual bright X-ray sources in the cloud to help us rule out a possible origin other than the black hole, ” staff member and postdoctoral researcher at Goddard Jenna Cann said. “But NGC 4945’s line extends so far from its center that we needed the wide XMM-Newton field of view to see it all.”
The team theorizes that this extraordinary feature is caused by jets of particles erupting from the supermassive black hole NGC 4945, 5 million years ago. They think that this jet was probably focused so it blasted through the galaxy rather than escaping the galactic plane.
This eruption caused a very strong wind that still blows in NGC 4945 as we see it today, and may also have started the galaxy’s period of intense starbursts.
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The team will now continue to look at NGC 4945 and search for other clues that show how the central black hole is influencing the galaxy’s evolution. They will also investigate whether the X-rays from the central region could disperse cold gas, ultimately driving intense star formation and quenching the phase of the NGC 4945 constellation.
“There are several lines of evidence indicating that black holes play important roles in some galaxies in determining their star formation histories and fates,” said Goddard team member and astrophysicist Edmund Hodges-Kluck. “We study many galaxies, like NGC 4945, because even though the physics is much the same from black hole to black hole, the effect they have on their galaxies varies greatly.”
“XMM-Newton helped us find a galactic fossil we didn’t know we were looking for – but it’s likely just the first of many.” Hodges-Kluck continued.
Weaver presented the team’s findings at the 243rd meeting of the American Astronomical Society in New Orleans, Louisiana, on Wednesday, January 11.
