The mysterious glows in the sky brighter than a trillion suns are actually the glow from two distant black holes orbiting each other, astronomers have confirmed in new observations that solve a decades-old mystery.
New research finds that the galaxy OJ 287, located 5 billion light-years from Earth in the constellation of Cancer, is anchored by two black holes, one supermassive and one smaller. Although these two black holes look like a single blob on telescope images, they send out different types of electromagnetic signals, allowing astronomers to decipher their identities.
The galaxy was discovered in 1888, and astronomers had suspected for decades that it might be a binary system, with two black holes at its core. The galaxy shows a pattern of emissions that vary in two separate cycles, one of 12-year duration and the other of 55-year duration, indicating that two separate types of motion are taking place – one, the orbit of one black hole around the other; The other, the slow change in the direction of that orbit.
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Years of observation have revealed flares that occur when one black hole plunges through the accretion disk of another – vast rings of material swirling around supermassive black holes – heating dust and gas from the disk and producing exciting flashes of energy across the electromagnetic spectrum. These flares are brighter than a trillion stars and last about two weeks. Now, though, researchers have observed two more dramatic and shorter-lived flares from the binary system, directly confirming the existence of the two black holes.
During the 2021-2022 observations, researchers led astronomers Staszk Zola from Jagiellonian University in Krakow, Poland, I witnessed a flare that produced 100 times as much light as an entire galaxy. This flash only lasted one day. NASA’s Fermi telescope detected a similarly short second Gamma rays glow. The short duration of these flares made them easy to miss for decades.
“OJ 287 has been recorded in photographs since 1888 and has been followed intensively since 1970,” lead author of the study. Maury Valtonen From the Tata Institute of Fundamental Research in Mumbai, India, V.A statement. “It turns out we simply had bad luck. No one noticed OJ 287 exactly those nights when it made its one-night drive.”
So what happened? Researchers have estimated that the smaller black hole in OJ 287 is about 150 million times the mass of our sun. The first giant flare occurred because this tiny black hole got a leak of new gas to swallow, creating a jet of material and shooting it out of the tiny black hole.
Soon after, the mini black hole passed through the accretion disk of the supermassive black hole, which has a mass 18 billion times that of our sun. The jet interacted with the disk, resulting in the gamma-ray glow detected by the Fermi telescope.
Combined, these two flares finally confirm that OJ 287 must be a double black hole system, in which the smaller object regularly passes through the gas disk of its larger neighbour.
The researchers report their findings in the June issue of Monthly Notices of the Royal Astronomical Society.
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