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From nasa Spitzer Space Telescope He may be removed, but the things he witnessed during his sixteen-and-a-half-year mission will be the subject of study for many years. For example, Spitzer It is the only telescope to witness something truly amazing happening in the center of the distant galaxy OJ 287: a supermassive black hole (SMBH) orbited by another black hole that regularly passes through its accretion disk.
When this happens, it causes a flash that is brighter than all the stars in the Milky Way combined. Using SpitzerBased on observations, an international team of astronomers was finally able to create a model that accurately predicts the timing of these flares and the orbit of the smallest black hole. In addition to proving General Relativity in action, his findings also validate Stephen Hawking’s “hairless hair theorem”.
Located 3.5 billion light-years from Earth, OJ 287 is what is known as a “blazar”, a galaxy with a particularly active nucleus and a jet of high-energy particles extending from its center. At its center is an SMBH that is approximately 18 billion times larger than our Sun, making it the largest ever discovered, while the black hole at the center of the Milky Way (Sagittarius A *) has approximately 40 solar masses.
For decades, astronomers have been aware of the binary nature of this black hole and have determined that its companion, which is 150 million times more massive than our Sun, completes an orbit once every 12 years. Twice in its orbit, the smallest black hole breaks through the huge disk of gas and dust surrounding its largest companion. These collisions create expanding hot gas bubbles that move away from the disk and are extremely bright.
These eruptions are known as Eddington eruptions, named for the 100th anniversary of Sir Arthur Eddington’s observations of the solar eclipse in 1919. This famous campaign validated the predictions made by Albert Einstein and his Theory of General Relativity, which had formalized. just four years earlier.
Due to the irregular orbit of the smallest black hole, it changes position with each 12-year orbit and tilts relative to the accretion disk. This means that it collides with the disk and creates flashes at different times during its cycle. As long as astronomers have known about the binary nature of these black holes, there have been attempts to create a model that can accurately predict the appearance of these eruptions.
In 2010, scientists first succeeded with a model that could predict these outbreaks in one to three weeks, which was confirmed when they predicted an outbreak in December 2015 in three weeks. For 2018, the same team responsible for this latest study released an even more accurate model that could predict a flash in four hours.
In their latest study, the team showed how Spitzer The data confirms that his model is correct because of how accurately he predicted a flare that occurred on July 31, 2019. The article describing his findings, titled “Spitzer’s Observations of Blazar OJ 287’s Predicted Eddington Flare,” appeared recently in the Astrophysical charts.
The observations were quite haphazard, since OJ 287 was on the opposite side of the Sun at the time. Fortunately, Spitzer’s wide orbit, which takes it to a maximum distance of 254 million kilometers (158 million miles) from Earth, allowed him to observe the galaxy on July 31, the same day an eruption was expected. Spitzer He was able to continue observing the galaxy until September, at which time the galaxy was no longer obscured by the Sun.
Seppo Laine, associate scientist on Caltech / IPAC staff and lead author of the team’s study, was responsible for monitoring Spitzer’s observations of the system. As stated in a recent NASA press release:
“When I first checked the visibility of OJ 287, I was surprised to find that it became visible to Spitzer just on the day the next flare was predicted to occur. It was extremely fortunate that we were able to capture the peak of this flare with SpitzerBecause no other man-made instrument was able to accomplish this feat at that specific time. “
The nature of OJ 287 is also expected to produce gravity waves that astronomers here on Earth will be able to detect using facilities like the Laser Interferometer Gravitational Wave Observatory (LIGO). In fact, the waves created by this system are expected to be so large and energetic that they will significantly alter the smallest orbit of the black hole (and thus the timing of the eruptions).
Previous studies of OJ 287 have been carried out that have taken into account gravitational waves, but the 2018 model is the most detailed to date. By including the information obtained by LIGO since 2015 in this model, the team was able to reduce the window in which an outbreak of just 1.5 days is expected. To further refine their predictions, they also included details on the physical characteristics of the largest black hole.
Specifically, the new model incorporates the “hairless” theorem of black holes, a theory originally proposed in the 1960s by a team of physicists that included Stephen Hawking. This theorem predicts that the “surface” of a black hole, or rather, its outer boundary (also known as the event horizon), is completely symmetric along its axis of rotation. This further reduced the team’s predictive model to just a few hours.
By predicting the orbit of the smallest black hole with this level of precision, the new model supports the no-hair theorem. This confirms yet another prediction, made by Caltech professor emeritus Kip Thorne, who in the 1970s described how an object orbiting an SMBH could reveal whether its surface was symmetrical or “hairy.”
Taking into account whether a black hole is smooth and symmetrical is important in determining the moment of the black hole’s smallest orbit. While an object’s orbit is predominantly a matter of mass, the distribution of that mass is also important. So if a black hole were “hairy,” it would have a noticeable effect on the orbit of anything around it.
In summary, the OJ 287 system supports the idea that the surfaces of black holes are symmetrical along their axes of rotation. “It is important to black hole scientists that we prove or disprove the no hair theorem,” said Mauri Valtonen, an astrophysicist at the University of Turku and co-author of the article. “Without it, we can’t trust black holes like those envisioned by Hawking and others.”
Such is the nature of missions like Spitzer. Long after retiring, their service record results continue to inspire discovery and advancement. Bye Spitzer and thanks for all the infrared data in the cosmos!
Further reading: NASA
