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The University of Michigan originally published this story in its Michigan News on October 28, 2024. Edits by EarthSky.<\/p>\n
Researchers led by the University of Michigan have pored over more than two decades of data from NASA\u2019s Chandra X-Ray Observatory, looking closely at the high-energy jet of particles being blasted across space by the supermassive black hole at the center of the giant galaxy Centaurus A.<\/p>\n
The new study is the latest effort in a small but growing body of research that\u2019s digging deeper into data to spot subtle, meaningful differences between radio and X-ray observations. <\/p>\n
David Bogensberger, lead author and a postdoctoral fellow at U-M said:<\/p>\n
\nA key to understanding what\u2019s going on in the jet could be understanding how different wavelength bands [for example, differences between the X-ray data and the radio data] trace different parts of the environment.<\/p>\n<\/blockquote>\n
Bogensberger explained:<\/p>\n
\nThe jet in X-rays is different from the jet in radio waves. The X-ray data traces a unique picture that you can\u2019t see in any other wavelength.<\/p>\n<\/blockquote>\n
Bogensberger and an international team of colleagues published their findings on October 18, 2024, in The Astrophysical Journal.<\/p>\n
appearance of superluminal speed due to its motion relative to Chandra\u2019s vantage point near Earth. The distance between the knot and Chandra shrinks almost as fast as light can travel.<\/p>\n
Still, the knot is moving fast<\/em>! The team determined its actual speed is at least 94% the speed of light. A knot in a similar location had previously had its speed measured using radio observations. That result clocked the knot with a slightly slower speed, about 80% of the speed of light. Bogensberger said:<\/p>\n
\nWhat this means is that [knots in the jet visible at radio wavelengths, and knots visible at X-ray wavelengths] move differently.<\/p>\n<\/blockquote>\n
That\u2019s a big clue as to what these knots might be, and how they behave. And that finding wasn\u2019t the only one that stood out from the data.<\/p>\n
For example, radio observations of knots suggested the structures closest to the black hole move the fastest. In the new study, however, Bogensberger and his colleagues found the fastest X-ray knot in a sort of middle region. It wasn\u2019t the farthest from the black hole, but it wasn\u2019t the nearest to it either. Bogensberger said:<\/p>\n
\nThere\u2019s a lot we still don\u2019t really know about how jets work in the X-ray band. This highlights the need for further research. We\u2019ve shown a new approach to studying jets, and I think there\u2019s a lot of interesting work to be done.<\/p>\n<\/blockquote>\n
The jet in Centaurus A is special to us because it\u2019s the closest supermassive black hole jet we know, at about 12 million light-years away. This relative proximity makes it a good first option for testing and validating new methodology. <\/p>\n
But, for his part, Bogensberger will be stepping further out from here, using the team\u2019s approach to examine other supermassive black hole jets, in other, more distant galaxies. Features like knots become more challenging to resolve in jets that are farther away. Bogensberger said:<\/p>\n
\nBut there are other galaxies where this analysis can be done. And that\u2019s what I plan to do next.<\/p>\n<\/blockquote>\n
Bottom line: There\u2019s new knotty science to discover around black holes. A new study looked at the high-energy jet of particles being blasted across space by the supermassive black hole at the center of the galaxy Centaurus A.<\/p>\n
Source: Superluminal Proper Motion in the X-Ray Jet of Centaurus A<\/p>\n
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