In images from the Hubble Telescope, scientists have seen a whole new phenomenon. When we reach tens of thousands of light-years into space, large shadows extend from the center of the galaxy IC 5063, as if something is blocking the bright light from there.
You’ve probably seen something like it before – bright rays from the sun when it’s just below the horizon, and clouds or mountains only partially block its light, known as crepuscular rays. According to astronomers, the shadows from IC 5063 could be something very similar. They are just much bigger – at least 36,000 light-years in each direction.
IC 5063, a galaxy 156 million light-years away, is a Seyfert galaxy. This means that it has an active core; the supermassive black hole in the center is rapidly penetrating from material from a dense recording disk and torus of dust and gas around it.
Although the supermassive black hole itself does not emit light, the intense forces involved in this massive growth process generate so much heat and light from the region around the black hole that the galactic core absolutely flames across space. It is this light, astronomers believe, that is being overshadowed. The obstacle? Probably caused by dust.
“We believe that we have found evidence that there is likely to be dust everywhere in the galaxy scattering light from the attractive black hole in the galaxy’s active core, and that light can illuminate almost the entire galaxy,” said astronomer Peter Maksym from Harvard Smithsonian Center for Astrophysics.
“We know that this galaxy recently had a fusion with another galaxy, and that could kick dust everywhere. It is also possible that the black hole rays are kicking dust up from near the core.”
The strange features were originally seen in December 2019 by amateur image processor Judy Schmidt. She processed raw data from new Hubble Space Telescope observations into images obtained in 2018 and 2019.
In the original images, there was no sign of the conical features. But Schmidt immediately saw something wrong.
“I noticed the dark rays almost immediately after I opened the file in Photoshop, and started working on improving them to make sure what I thought I saw was there,” Schmidt explained.
“Even after I treated it, I constantly blinked my eyes and wondered if I saw what I thought I saw,” she added.
She posted her strange discovery on Twitter, and astronomers – including Maksym – were immediately fascinated. He and colleagues who were already working on jets produced by IC 5063’s supermassive black hole were given work on studying the strange shady shapes.
They used near-infrared observations taken in March and November with the Hubble Space Telescope’s Wide Field Camera 3. At these wavelengths, the instrument can look through the dust for a better understanding of the center of galaxies.
Based on the team’s analysis, there could be holes or clear paths in the torus of dust and gas that hide the inner core of IC 5063. If the black hole was tilted to the side relative to the galactic plane, there would be some light from the galactic core would be blocked by the denser regions of the torus, but some slipped out through these holes, creating colossal galactic crepuscular rays.
The holes had to be stable for at least 36,000 years for the rays to create more or less uniform straight lines. This places some constraints that could help astronomers better understand the dynamics of play at the center of a galaxy 156 million light-years away.
If it is the torus that is responsible, it tells us that the structure is quite thin and can be twisted by torque in the galactic center.
“The discovery shows that the torus or ring can be very thin – the light appears to come out almost everywhere. If the torus is large enough, it becomes unstable, gravity and the rotation that holds it together point in a direction near the black hole and “in a different direction as influences from the galaxy begin to become important. This looks like a chain or a bend,” Maksym said.
“Scientifically, it shows us something that is difficult – usually impossible – to see directly. We know this phenomenon is going to happen, but in this case we can see the effects throughout the galaxy. Knowing more about the geometry of the torus will have consequences. anyone trying to understand the construction of supermassive black holes and their surroundings. “
Because this is the first time we’ve actually seen this, it may take some time to reveal what’s actually going on. There are other options that are not yet ruled out. A mysterious encounter could have created unusual X-shaped star orbits. The destruction of dust by hot outflows from the galactic core is also not completely ruled out, although the team notes that it seems unlikely, based on their modeling.
The next step will be to take more observations in other wavelengths with a range of instruments and use this new data as a basis for performing detailed modeling.
“This is a project that is just begging for new data because it raises more questions than it answers,” Maksym said.
The research is published in The Astrophysical Journal Letters.