Wednesday, September 20, 2017

Discovery of the Closest Binary Supermassive Black Hole System in the Galaxy NGC 7674

The two compact radio sources separated by less than a light year at the center of the galaxy NGC 7674. The two sources correspond to the location of the two active supermassive black holes which form a binary and orbit around each other. Credit: TIFR-NCRA and RIT, USA

Dr. Preeti Kharb and Dr. Dharam Vir Lal from NCRA-TIFR, Pune, and David Merritt from the Rochester Institute of Technology, USA, have discovered the closest ever binary supermassive black hole system in a spiral galaxy named NGC 7674, located about 400 million light years from earth. The apparent separation of the two black holes in the binary system is less than one light year. This is much less than the previous record holder, which was a black hole binary with a separation of about 24 light years.

This discovery is very significant because this is a direct observational proof of the existence of close supermassive black hole binary systems inside galaxies, which are potential sources of gravitational waves.

Black holes are among most fascinating objects and even more the binary black-holes (two black holes orbiting around each other). The existence of binary black holes, roughly ten times the mass of Sun, got confirmed by the recent detection of gravitational waves by the LIGO telescope in 2015.

Astrophysicists have long predicted the existence of a second class of binaries, consisting of supermassive black holes, each having a mass upwards of one million times the mass of the Sun. Single supermassive black holes are known to be present at the centers of most galaxies, and since galaxies are observed to merge with other galaxies, it is possible to form gravitationally bound black hole pairs. In due course of time, these two supermassive black holes would coalesce via the emission of gravitational waves.

The above binary system was detected using a technique called very long baseline interferometry (VLBI), in which separate radio telescopes around the world can work together as a single large telescope, achieving an angular resolution of milli- or microarcseconds - roughly ten million times the angular resolution of the human eye. Using VLBI techniques, two compact sources of radio emission were detected at the center of NGC 7674. "The two radio sources have properties that are known to be associated with massive black holes that are accreting gas," Preeti Kharb said, "implying the presence of two black holes." The combined mass of the two black holes is roughly forty million times the mass of the Sun. Kharb et al. estimate the orbital period of the binary to be about one hundred thousand years.

"Detection of a binary supermassive black hole in this galaxy also confirms a theoretical prediction that such binaries should be present in so-called Z-shaped radio sources," David Merritt stated. NGC 7674 is such a radio source. The name "Z-shaped" refers to the twisted morphology of the galaxy's radio emission on much larger scales. This morphology is thought to result from the combined effects of the galaxy merger followed by the formation of the massive binary.

Credit: eurekalert.org

2 comments:

  1. It is quite probable, but it is impossible for any interferometer based GW receiver to sense such a GW wave from a future merger of these reported suspected black holes. It is impossible, even, if the interferometer is thousands of miles long. Primarily, because, gravity still travels at infinite speed as proposed by Newton; Einstein, indeed, could not change the speed. Let me add, 6 years earlier, minuscule gravitational waves of a wide frequency range (nearly zero to around 3 KHz) were first produced and detected in my lab late in 2010 and were reported in a US patent application which now is a US patent 8521029. You can find the patent detail on the USPTO site as well as on google patents . You can check out gravitational waves and my work on Wikipedia. Let me also add, even if I am letting out a little secret, it is impossible to register any black hole mergers otherwise too, primarily because of the sheer volume of mergers — I cannot talk more on this subject — besides due to too much of GW noise present around us (read in my patent about how this noise is generated). So, let me tell you, LIGO actually never detected any black hole mergers in the past too. The least I can say is that the reported mergers were a result of the intense imagination of the LIGO folks, to say the least. Unless LIGO is not confident of their so-called GW wave findings from BH mergers, why should they be tweeting this research with excitement? Then let us not forget it is a finding by a low-credibility Indian team and India has staked USD300 million for a disused LIGO setup to be shipped to India with a new name INDIGO.

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    1. Anadish Kumar Pal, I will suggest to make your theories factually correct, Gravitaional Waves are quite real and travel at speed of light [not infinite speed] GW are not based on Newtonian Mechanics. LIGO and it's work has confirmed the works of This Year's Nobel Laureates in Physics. Definitely your claim of LIGO's findings being imagination, is factually wrong. I suggest, please read on what You are opposing, and your claims are not backed Scientifically [Yes you have patents, but LIGO works at much more Sensitivity, and please study the Scientific concepts behind it, and dont claim thing like why they tweeted, they tweeted it after getting the assurance of publication for results.]

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