Beijing, April 4 (ZXS) -- More than four years ago, the Event Horizon Telescope (EHT) simultaneously released a major astronomical achievement completed by more than 27 scientists around the world - the first black hole photo of mankind.
This direct visual evidence of the first "seeing is believing" supermassive black hole reveals the black hole at the center of the supermassive galaxy M87 in the Virgo cluster, which is 5500 million light-years from Earth and has a mass of 65.4 billion times that of the Sun. Now, 87 years later, has the M<> black hole changed? What are the advances in scientific research? Have you taken any new photos?
Black hole shadows and powerful jets are imaged in the same frame for the first time
Schematic diagram of the joint observation imaging process of the M87 black hole. Photo courtesy of Shanghai Astronomical Observatory, Chinese Academy of Sciences
According to the latest news from the Chinese Academy of Sciences (CAS), an international research team led by Lu Rusen, a researcher at the Shanghai Astronomical Observatory of the Chinese Academy of Sciences and leader of the Sino-German Mapp Partnership Group, used the latest observations in the 3.5 millimeter band to image for the first time the black hole shadow of the famous radio galaxy M87, as well as the ring-like structure of the material falling into the central black hole around it and the powerful relativistic jets. The "panorama" of the black hole's shadow in the same frame as the powerful jet is the first to be imaged at a wavelength of 3.5 millimeters, and it is also the first to show the connection between the accretion flow near the central supermassive black hole and the origin of the jet.
The M87 image observations were obtained by the Global Millimeter Wave Very Long Baseline Interferometry Array (GMVA) in conjunction with the Atacama Large Millimeter/submillimeter Array (ALMA) and the Greenland Telescope (GLT), and the addition of the latter two observing stations greatly enhanced the imaging capabilities of GMVA.
On the night of April 4, Beijing time, the first co-frame image of the M26 black hole shadow and powerful jet and related results jointly completed by 17 researchers from 64 research units in 121 countries and regions were published online in the top international academic journal Nature.
New band captures "panorama" of black holes and jets
Image of the M87 black hole at a wavelength of 3.5 mm (source: SHAO, MPIfR, NRAO/AUI/NSF). Photo courtesy of Shanghai Astronomical Observatory, Chinese Academy of Sciences
Researcher Lu Rusen, the first author of the paper, said that the matter around the black hole is thought to fall into the black hole in a process called accretion, but no one has ever directly imaged it before. "Previously we have seen black holes and jets separately in separate images, but now we have taken a 'panorama' of black holes and jets in a new band," and "the ring-like structure we saw earlier became larger and thicker at a wavelength of 3.5 mm, suggesting that in the new image we can see that the matter falling into the black hole produces additional radiation, allowing us to get a fuller picture of the physical processes around the black hole."
He noted that the new lineup of ALMA, GLT and GMVA improves the resolution and sensitivity of telescope arrays around the world, allowing astronomers to image the ring-like structure around M3's black hole at 5.87 millimeters for the first time. The new image of the M87 black hole was taken on April 2018-4, 14, and after a complex data processing and mapping process, as well as repeated verification and confirmation of the results, it took 15 years to "develop" and present this unprecedented new image.
Compared with the first photograph of a black hole released four years ago, this observation has a wavelength of 4.3 mm and combines 5 telescopes, while EHT has a wavelength of 16.1 mm and combines 3 telescopes. "The image taken by the EHT is a 'close-up' of the black hole, with a bright ring seen around the shadow in the middle. This time, we took a 'panorama' of the black hole, which shows the black hole, the accretion flow around the black hole, and the jets extending from near the disk into the distance. This image is an extension of the EHT image, which fully shows the relationship between the black hole and its surroundings. Lu Rusen explained popularly.
New observations reveal black holes themselves are not "very hungry"
Distribution map of 87 telescope stations for the joint observation of the M16 black hole. Photo courtesy of Shanghai Astronomical Observatory, Chinese Academy of Sciences
Co-author Thomas Krichbaum, Germany's Max Planck Institute for Radio Astronomy, believes that "now we can see how jets emerge from the ring structure around the central supermassive black hole, and it is also possible to measure the diameter of the ring structure around the black hole in another band."
The team at the Shanghai Observatory of the Chinese Academy of Sciences noted that at a wavelength of 3.5 millimeters, the new observations also reveal something about the nature of the black hole itself: it is not "very hungry", its rate of consumption of matter is very low, and only a small part of it is converted into radiation.
Co-author Keiichi Asada, of the Institute of Astronomy and Astrophysics at the Academia Sinia in Taiwan, explains: "To understand the physical origin of the larger, thicker ring of the M87 black hole, we had to use computer simulations to test different scenarios and finally concluded that the larger range of the bright ring is related to accretion flow." Co-author Kazuhiro Hada of Japan's National Astronomical Observatory added that the observations also found that the width of radiation in the inner region close to the black hole is wider than expected. This could mean that not only is gas falling around the black hole, but there may also be a "wind" blowing out, causing turbulence and chaos around the black hole.
In the future, "colored black holes" and "dynamic black holes" will be photographed
M87 Black Hole Art Imagination. Photo courtesy of Shanghai Astronomical Observatory, Chinese Academy of Sciences
The research team of the Shanghai Astronomical Observatory of the Chinese Academy of Sciences said that although the "close-up" and "panorama" photos of the black hole have been taken, astronomers' exploration of the M87 black hole is not over, and subsequent further observations and more powerful telescope arrays in the future will continue to uncover its mysteries.
Lu Rusen revealed that the next goal of the research team is to shoot the "color black hole" with EHT. The so-called "color" is to take pictures of black holes at different observation wavelengths to obtain "color photos" of black holes, which will give astronomers more information and help better understand the black hole itself and its relationship with the surrounding environment; The second is to shoot "dynamic black holes". A black hole is not stationary, it interacts with its surroundings all the time, so it looks different at different times. Photographing "dynamic black holes" will unlock the time dimension in the spatial dimension, allowing astronomers to observe and understand black holes in all aspects.
Jongho Park of the Korea Institute of Astronomy and Space Science, a co-author and member of the research team, believes that future millimeter-wave observations will study the temporal evolution of the M87 black hole and will obtain a multicolor view of the central black hole region of M87 by combining images of different colors of "radio light".
"The 3.5 mm wavelength image presented this time can be said to represent the latest achievement, but in order to unravel the mystery of the physical mechanism of the formation, acceleration and collimation propagation of the central supermassive black hole of M87 and its relativistic jet, we need to take more high-quality images of color." The future is very exciting. Professor Shen Zhiqiang, co-author of the paper and director of the Shanghai Astronomical Observatory of the Chinese Academy of Sciences, concluded and emphasized. (End)