On February 2, 2016, NASA released this image showing a spectacular jet emanating from a supermassive black hole in the center of the Pictor A galaxy, located nearly 500 million light-years from Earth. Material falling onto the black hole is driving an enormous beam, or jet, of particles traveling at nearly the speed of light into intergalactic space. The jet extends across 300,000 years toward a brilliant hotspot and a counter jet pointing in the opposite direction.
To obtain images of this jet, scientists used NASA’s Chandra X-ray Observatory at various times over 15 years. Chandra’s X-ray data (blue) have been combined with radio data from the Australia Telescope Compact Array (red) in this new composite image.
The jet in Pictor A displays continuous X-ray emission over a distance of 300,000 light-years. By comparison, the entire Milky Way is about 100,000 light-years in diameter.
In addition to the prominent jet seen pointing to the right in the image, researchers report evidence for another jet pointing in the opposite direction, known as a counterjet. While tentative evidence for this counterjet had been previously reported, these new Chandra data confirm its existence. The relative faintness of the counterjet compared to the jet is likely due to the motion of the counterjet away from the line of sight to the Earth.
The labeled image shows the location of the supermassive black hole, the jet and the counterjet. Also labeled is a “radio lobe” where the jet is pushing into surrounding gas and a “hotspot” caused by shock waves – akin to sonic booms from a supersonic aircraft – near the tip of the jet.
The detailed properties of the jet and counterjet observed with Chandra show that their X-ray emission likely comes from electrons spiraling around magnetic field lines, a process called synchrotron emission. In this case, the electrons must be continuously re-accelerated as they move out along the jet. How this occurs is not well understood.
A paper describing these results will be published in the Monthly Notices of the Royal Astronomical Society and is available online.
Bottom line: A new image, released by NASA on February 2, 2016, uses data from NASA’s Chandra X-ray Observatory and the Australia Telescope Compact Array to show a spectacular jet of particles emanating from a supermassive black hole in the center of the Pictor A galaxy, located nearly 500 million light-years from Earth. The jet extends across 300,000 years toward a brilliant hotspot and a counter jet pointing in the opposite direction.