Country: In 2019, the Event Horizon Telescope gave the first direct image of a black hole in the galaxy, as the image was strong, but it was not in many details, as a recent study showed that the EHT image does not show the glow of the black hole itself, and black holes do not emit light directly .
Unlike the less detailed images of supermassive black holes we have, the glow is not due to jets of plasma or radiation from superheated gas around the black hole, but rather the radio light that was focused by the black hole.
The black hole in M87 is immersed in nearby gas light, including radio light, and when a certain beam of light passes near the black hole, the warp in spacetime causes it to change its direction slightly.
The slight deviation of light from things like stars and galaxies has been observed many times.
Light can change direction dramatically if it is near the black hole, where it can rotate around it at a right angle, or even end up returning from the direction it came in, and the closer the path is to the black hole, the more radical the change in direction.
Light passes near a black hole in all kinds of directions, as it turns out that a black hole can act as a really powerful lens. Light can pass very close to it, as we can only see light directed towards us, often in the form of a thin circle of light known as a ring Photon.
Part of the light will be brighter because the rotation of the black hole also gives the light a boost of energy. The size of the ring depends on the mass of the black hole, and the brightness of the brighter region depends on the rotation of the black hole.
There is still a region surrounding the cold gas, through which light must pass to reach us, but some of the light is scattered along the way, making the image more blurry than we’d like, and that’s where the new study comes in.
The diffuse glow of the EHT image tells us not only regarding the black hole but also regarding the diffuse gas surrounding the black hole. The team noticed that there are two primary images in the EHT data, one of which is the photon ring itself, and the other of the hazy glow of the surrounding area.
Using new imaging algorithms, the team was able to separate the two, revealing the black hole’s photon ring.
Source: RT
