Astronomers using the NASA/ESA Hubble Space Telescope have observed spectacular large-scale dark and light rays beaming out of the bright center of IC 5063, an active galaxy located 156 million light-years away in the southern constellation of Indus. The researchers think that an inner-tube-shaped ring, or torus, of dusty material surrounding IC 5063’s central black hole is casting its shadow into space. According to their scenario, this interplay of light and shadow may occur when light blasted by the supermassive black hole strikes the torus; light streams through gaps in the torus, creating the brilliant cone-shaped rays; however, denser patches in the torus block some of the light, casting long, dark shadows through the galaxy.
This Hubble image of the nearby active galaxy IC 5063 reveals a mixture of bright rays and dark shadows coming from the blazing core, home of a supermassive black hole. Image credit: Credits: NASA / ESA / Hubble / STScI / W.P. Maksym, CfA.
“I’m most excited by the shadow of the torus idea because it’s a really cool effect that I don’t think we’ve seen before in images, although it has been hypothesized,” said Dr. Peter Maksym, an astronomer at the Harvard & Smithsonian Center for Astrophysics.
“Scientifically, it’s showing us something that is hard — usually impossible — to see directly.”
“We know this phenomenon should happen, but in this case, we can see the effects throughout the IC 5063 galaxy.”
“Knowing more about the geometry of the torus will have implications for anybody trying to understand the behavior of supermassive black holes and their environments.”
“As a galaxy evolves, it is shaped by its central black hole.”
Studying IC 5063’s torus is important because it funnels material toward the black hole.
If the ‘shadow’ interpretation is accurate, the dark rays provide indirect evidence that the disk in IC 5063 could be very thin, which explains why light is leaking out all around the structure.
Observations of similar black holes by NASA’s Chandra X-ray Observatory detected X-rays leaking out of holes in the torus.
“The holes may be caused by the disk being torqued by internal forces, causing it to warp,” Dr. Maksym said.
“It’s possible that the warping creates big enough gaps for some of the light to shine through, and as the torus rotates, beams of light could sweep across the galaxy like lighthouse beams through fog.”
Although astronomers have been studying the galaxy for decades, it took a non-scientist to make the surprising discovery.
Judy Schmidt, an artist and amateur astronomer based in Modesto, California, uncovered the dark shadows when she reprocessed Hubble exposures of IC 5063 in December 2019.
She selected the Hubble observations of the galaxy from the archive because she is interested in galaxies that have active cores.
The cone-shaped shadows were not apparent in the original exposures, so Schmidt was surprised to see them in her reprocessed image.
“I had no idea they were there, and even after I’d processed it, I kept blinking my eyes wondering if I was seeing what I thought I was seeing,” Schmidt said.
This discovery would not have been possible without Hubble’s sharp vision.
“Older images from telescopes on the ground showed maybe hints of this kind of structure, but the galaxy itself is such a mess that you’d never guess that this is what’s going on without Hubble,” Dr. Maksym said.
“Hubble has sharp pictures, is sensitive to faint things, and has a big enough field of view to image the entire galaxy.”
The findings will be published in the Astrophysical Journal Letters.
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W. Peter Maksym et al. 2020. A Giant Loop of Ionized Gas Emerging from the Tumultuous Central Region of IC 5063. ApJ, in press; arXiv: 2010.14542
This article is based on a press-release provided by the National Aeronautics and Space Administration.
