নাসার infra-red observatory Spitzer has recently observed the flare from gigantic binary কৃষ্ণ গহ্বর 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 মহাকর্ষীয় তরঙ্গ.
সার্জারির ওজে ঘ ছায়াপথ, situated in Cancer constellation 3.5 billion light years away from Earth, has two কালো গর্ত – the larger one with over 18 billion times the ভর of the Sun and orbiting this is a smaller কৃষ্ণ গহ্বর with about 150 million times the solar ভর, and they form a binary কৃষ্ণ গহ্বর system. While orbiting the larger one, the smaller কৃষ্ণ গহ্বর crashes through the enormous accretion disk of gas and dust surrounding its larger companion, creating a flash of light brighter than a trillion নক্ষত্র.
ছোট কৃষ্ণ গহ্বর collides with the accretion disk of the larger one twice in every twelve years. However, due to its irregular oblong কক্ষপথ (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 কক্ষপথ 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 কৃষ্ণ গহ্বর system OJ 287 is the fact that supermassive কালো গর্ত can be sources of মহাকর্ষীয় তরঙ্গ – which has been established after the experimental observation of the মহাকর্ষীয় তরঙ্গ in 2016, produced during the merging of two supermassive কালো গর্ত. OJ 287 has been predicted to be the source of infra-red মহাকর্ষীয় তরঙ্গ (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 নাসার স্পিটজার স্থান 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 কক্ষপথ, 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 মহাকর্ষীয় তরঙ্গ 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.
এই শিখাগুলির পর্যবেক্ষণগুলি "চুলের উপপাদ্য নেই” (5,6) which states that while কালো গর্ত 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 কৃষ্ণ গহ্বর event horizon and is therefore permanently inaccessible to external observers, suggesting that কালো গর্ত have “no hair”. One immediate consequence of the theorem is that the কালো গর্ত can be characterized completely with their ভর, 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 স্থান around it in such a manner that it would lead to a change of path of the smaller কৃষ্ণ গহ্বর, and in turn change the timing of the black hole’s collision with the accretion disk on that particular কক্ষপথ, thus causing a change in the time of appearance of the flares observed.
যেমনটা আশা করা যায়, কালো গর্ত are hard to probe. Hence, as we move forward, many more experimental observations regarding কৃষ্ণ গহ্বর 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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তথ্যসূত্র:
- ভ্যালটোনেন ভি., জোলা এস., এট আল. 2016, "OJ287-এ প্রাথমিক ব্ল্যাক হোল স্পিন যেমন জেনারেল রিলেটিভিটি সেন্টেনারি ফ্লেয়ার দ্বারা নির্ধারিত", অ্যাস্ট্রোফিস৷ জে. লেট। 819 (2016) নং 2, L37। DOI: https://doi.org/10.3847/2041-8205/819/2/L37
- অ্যাবট বিপি।, এট আল. 2016. (LIGO Scientific Collaboration and Virgo Collaboration), “Abservation of Gravitational Waves from a Binary Black Hole Merger”, Phys. রেভ. লেট। 116, 061102 (2016)। DOI: https://doi.org/10.1103/PhysRevLett.116.061102
- দে এল., ভালটনেন এমজে., গোপকুমার এ. এট আল 2018. "OJ 287 এর সাধারণ আপেক্ষিক শতবর্ষী ফ্লেয়ার ব্যবহার করে একটি আপেক্ষিক বিশাল ব্ল্যাক হোল বাইনারির উপস্থিতি প্রমাণীকরণ: উন্নত অরবিটাল প্যারামিটার", অ্যাস্ট্রোফিস। জে. 866, 11 (2018)। DOI: https://doi.org/10.3847/1538-4357/aadd95
- লেইন এস., ডে এল., এট আল 2020. "ব্লাজার ওজে 287 থেকে পূর্বাভাসিত এডিংটন ফ্লেয়ারের স্পিটজার পর্যবেক্ষণ"। Astrophysical Journal Letters, vol. 894, নং 1 (2020)। DOI: https://doi.org/10.3847/2041-8213/ab79a4
- Gürlebeck, N., 2015. "অ্যাস্ট্রোফিজিক্যাল এনভায়রনমেন্টে ব্ল্যাক হোলসের জন্য নো-হেয়ার থিওরেম", দৈহিক পর্যালোচনা চিঠি 114, 151102 (2015)। DOI: https://doi.org/10.1103/PhysRevLett.114.151102
- Hawking Stephen W., et al 2016. ব্ল্যাক হোলসের উপর নরম চুল। https://arxiv.org/pdf/1601.00921.pdf
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