NASA’s infra-red observatory Spitzer has recently observed the flare from gigantic binary schwarzes Loch system OJ 287, within the estimated time interval predicted by the model developed by astrophysicists. This observation has tested different aspects of General Relativity, the “No-hair theorem”, and proved that OJ 287 is indeed a source of infra-red Gravitationswellen.
Das ABl. 287 galaxy, situated in Cancer constellation 3.5 billion light years away from Earth, has two Schwarze Löcher – the larger one with over 18 billion times the mass of the Sun and orbiting this is a smaller schwarzes Loch with about 150 million times the solar mass, and they form a binary schwarzes Loch system. While orbiting the larger one, the smaller schwarzes Loch crashes through the enormous accretion disk of gas and dust surrounding its larger companion, creating a flash of light brighter than a trillion stars.
Der kleinere schwarzes Loch collides with the accretion disk of the larger one twice in every twelve years. However, due to its irregular oblong orbit (called quasi-Keplarian in the mathematical terminology, as shown in the figure below), the flares can appear at different times – sometimes as little as one year apart; other times, as much as 10 years apart (1). Several attempts to model the orbit and predicting when flares would happen were unsuccessful until in 2010, when astrophysicists created a model that could predict their occurrence with an error of about one to three weeks. The accuracy of the model was demonstrated by predicting the appearance of a flare in December 2015 to within three weeks.
Another important piece of information that went into the making of a successful theory of binary schwarzes Loch system OJ 287 is the fact that supermassive Schwarze Löcher can be sources of Gravitationswellen – which has been established after the experimental observation of the Gravitationswellen in 2016, produced during the merging of two supermassive Schwarze Löcher. OJ 287 has been predicted to be the source of infra-red Gravitationswellen (2).
In 2018, a group of astrophysicists provided an even more detailed model, and claimed to be able to predict the timing of future flares to within few hours (3). According to this model, the next flare would occur on July 31, 2019 and the time was predicted with an error of 4.4 hours. It also predicted the brightness of the impact-induced flare to take place during that event. The event was captured and confirmed by NASA’s Spitzer Space Telescope (4), which retired in January 2020. To observe the predicted event, Spitzer was our only hope since this flare could not be seen by any other telescope on the ground or in Earth’s orbit, as the Sun was in Cancer constellation with OJ 287 and Earth being on opposite sides of it. This observation also proved that OJ 287 emits Gravitationswellen in the infra-red wavelength, as predicted. According to this proposed theory the impact-induced flare from OJ 287 is expected to take place in 2022.
Die Beobachtungen dieser Flares schränken die „Kein Haarsatz” (5,6) which states that while Schwarze Löcher don’t have true surfaces, there is a boundary around them beyond which nothing – not even light – can escape. This boundary is called the event horizon. This theorem also postulates that the matter which forms a black-hole or is falling into it “disappears” behind the schwarzes Loch event horizon and is therefore permanently inaccessible to external observers, suggesting that Schwarze Löcher have “no hair”. One immediate consequence of the theorem is that the Schwarze Löcher can be characterized completely with their mass, electric charge and intrinsic spin. According to some scientists, this outer edge of the black-hole, i.e. the event horizon, could be bumpy or irregular, thus contradicting the “No hair theorem”. However, if one has to prove the correctness of the “No hair theorem”, the only plausible explanation is that the uneven mass distribution of the large black-hole would distort the space around it in such a manner that it would lead to a change of path of the smaller schwarzes Loch, and in turn change the timing of the black hole’s collision with the accretion disk on that particular orbit, thus causing a change in the time of appearance of the flares observed.
Wie zu erwarten ist, Schwarze Löcher are hard to probe. Hence, as we move forward, many more experimental observations regarding schwarzes Loch interactions, with the surroundings as well as with other black holes, are to be studied before one can confirm the validity of the “No hair theorem”.
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References:
- Valtonen V., Zola S., et al. 2016, „Primary Black Hole Spin in OJ287, wie durch die Allgemeine Relativitätstheorie Centenary Flare bestimmt“, Astrophys. J. Lett. 819 (2016) Nr. 2, L37. DOI: https://doi.org/10.3847/2041-8205/819/2/L37
- Abbott BP., et al. 2016. (LIGO Scientific Collaboration und Virgo Collaboration), „Beobachtung von Gravitationswellen aus einer Verschmelzung binärer Schwarzer Löcher“, Phys. Rev. Lett. 116, 061102 (2016). DOI: https://doi.org/10.1103/PhysRevLett.116.061102
- Dey L., Valtonen MJ., Gopakumar A. et al 2018. "Authentifizierung der Anwesenheit eines relativistischen massereichen Schwarzen Lochs in OJ 287 unter Verwendung seines hundertjährigen Flare der Allgemeinen Relativitätstheorie: Verbesserte Orbitalparameter", Astrophie. J. 866, 11 (2018). DOI: https://doi.org/10.3847/1538-4357/aadd95
- Laine S., Dey L., et al 2020. „Spitzer Observations of the Predicted Eddington Flare from Blazar OJ 287“. Astrophysical Journal Letters, vol. 894, Nr. 1 (2020). DOI: https://doi.org/10.3847/2041-8213/ab79a4
- Gürlebeck, N., 2015. „No-Hair Theorem for Black Holes in Astrophysical Environments“, Physical Review Letters 114, 151102 (2015). DOI: https://doi.org/10.1103/PhysRevLett.114.151102
- Hawking Stephen W., et al. 2016. Weiches Haar auf Schwarzen Löchern. https://arxiv.org/pdf/1601.00921.pdf
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