Event Horizon Telescope (EHT) researchers produced the first ever image of a black hole in 2019, and it showed a donut-shaped light from hot matter spinning around the black hole’s dark silhouette (SN: 4/10/19). However, general relativity as developed by Albert Einstein predicts that a thin ring should be overlaid on that thick donut. Light particles (photons) in orbit around the black hole are swung about by the monster’s gravity and then send forth, creating the ring that eventually reaches Earth.
Avery Broderick, an astrophysicist from the University of Waterloo and the Perimeter Institute for Theoretical Physics in Canada, explains that this orbit will allow photons to produce a ‘gravitational fingerprint’ and better characterize the black hole. He and his colleagues are a subset of the EHT collaboration’s experts. Using new techniques to extract the fingerprint, they published their findings in an astrophysics journal on August 10.
EHT image creation is not a simple autofocus (SN: 4/10/19). Using a variety of computer tools, the researcher will assemble data from his globally dispersed team of EHT observatories in order to rebuild the image. Broderick and his coworkers have developed a novel depiction of a black hole with diffuse radiation and thin rings. The data were more in accord with the image with the thin ring added than with the image without the ring on three of the four days of observation.
Nevertheless, the method has been harshly criticized. Sam Gralla, a physicist at the University of Arizona in Tucson, refutes the idea that the photon he detected possesses a ring. The photon ring is brighter than anticipated, emitting approximately 60 percent of the image’s light. According to estimates, it should be approximately 20%. According to Alex Lupsaska, a physicist at Vanderbilt University in Nashville, this is a red flag. “The primary blazing donut of the black hole should emit more light than the thin photon ring.
According to Broderick and his colleagues, this unexpected brightness is caused by the concentration of light from the primary glow on the photon ring. Therefore, the apparent brightness of the ring does not simply depend on the ring’s own light. The researchers highlight that the same impact occurred when simulating data to evaluate the strategy.
Critics assert that combining the putative photon ring light with other lights does not result in particularly compelling detections. In the new research, Dan Malone, an astronomer at the University of Arizona, states, “If you want to claim to have seen a photon ring, you need to do a better job than this.” The new results, according to Marrone, merely indicate that the thin ring added better fits the data, not whether its shape is related to the photon ring. This raises the question of whether scientists are observing photon rings or merely recognizing unrelated objects in photos.
Broderick contends, however, that the ring’s characteristics—that is, its size and location—are predictable and consistent on a daily basis, hence confirming the photon ring explanation. Will Lockhart, a physicist at the University of Arizona, conducted an independent analysis comparable to Gralla’s and discovered no evidence of a photon ring, as reported in a manuscript uploaded to arXiv.org on August 22. Their analysis was in part dissimilar to that of Broderick et al. This is due to the fact that it reduced the luminosity of the photon ring.
For the EHT observatory to successfully detect the photon ring, several scientists have proposed adding a space telescope to the team (SN: March 18, 2020). In a network, telescopes farther apart have the capacity to detect more specific data. This could contain photon rings. Lupsaska predicts that the discovery of the photon ring will be the most significant development in physics this year, if not for many years.