Black holes are the most Baffling, Bashful and Boisterous objects that always steal the heart of science lovers. For the astronomers and for many other people, it is a supervillain. Sometimes these fabulous things can be related to ferocious Beasts. This Massive Black Evil always hunts down the stars which are in its vicinity. Even light cannot escape from its huge gravity trap.
Last day NASA published an article. It was about an intermediate version of this supervillain. Intermediate..? What does that actually mean..? Who is this new guy..?
Oh..okay, it’s not a new guy but not much familiar; the Intermediate-mass black hole.
So there must be a younger and old version of this big buddy, isn’t? Yeah, exactly. Most of us might have heard about the Supermassive black hole (the Big old one); one at the centre of galaxies. Another one is the stellar-mass black hole; the teenager one among the 3 stages of black hole evolution.
Stellar-mass black holes are born as per the theory that everyone must have already known from their childhood textbook. These black holes are formed by the gravitational collapse of a star. When all stellar energy sources are exhausted, the star will step into its final stage which can be related to the concept of ‘life after death’. If the mass of the collapsing part of the star is below the Tolman–Oppenheimer–Volkoff (TOV) limit for neutron-degenerate matter, the end product is a compact star — either a white dwarf (for masses below the Chandrasekhar limit) or a neutron star or a hypothetical quark star. If the collapsing star has a mass exceeding the TOV limit, the crush will continue until zero volume is achieved and a black hole is formed around that point in space. The largest known mass of a stellar-mass black hole was 15.65±1.45 solar masses. The lowest one has a mass of 5 to 10 solar masses. These black holes are comparable to the zombies, which are supposed to be living dead. Like zombie eating its former form, the black hole engulfs and destroy other stars around it to become more Boisterous. The stellar-mass black holes can be a few hundred times the solar mass.
Few hundreds! Is that a small number!!
Mm. Yeah, compared to the big guy at the centre of the galaxy; Supermassive black holes which are not hundred times, not thousands, not even millions but several billion times the mass of the sun. These big giant black holes are the most attractive one in our universe, which mostly active by producing jets and emitting x-rays. Like the recently found big explosion in Ophiuchus galaxy cluster.
But a guy was missing in between them. Scientists were in search of that object, known as an intermediate-mass black hole (IMBH). This black hole has a mass in the range of 1000 to 1 lakh times the mass of the sun. This black hole is a very mysterious one among the three. It is very difficult to find this black hole. Because they are mostly inactive and present in some star clusters. They are a kind of silent killer. They hide behind the darkness and engulf the stars which pass close to it. As a result, it emits radiations and jets and becomes active for some years. This scenario can be related to a giant monster producing burp after eating humans.
Due to this mysterious nature, no one could easily find this type of black holes. Few of IMBHs have been observed by our scientists. But there were many doubts in each invention and no one was ever fully satisfied. So scientists were actually looking for perfect observational evidence. Even the HLX-1 was not 100% acceptable. Because to show it’s an IMBH it should exhibit its ferocious behaviour of engulfing the stars. Since HLX-1 was always an active one, scientists were unable to find such an event happening there.
Scientists have been searching for that kind of event to occur in space. They finally got one. Yeah. With the help of observation made by NASA’s Chandra X-ray Observatory, Hubble Space Telescope, and ESA’s XMM-Newton they found huge multi-wavelength flare of radiations from the outskirts of a galaxy 740 million light-years away. The study and continuous observations on its spectral shapes and X-ray luminosity revealed that it was an intermediate-mass black hole. They named it as 3XMM J215022.4−055108 (or J2150−0551 for short). They found this rays are from a globular cluster or more likely a remnant nucleus of a tidally stripped dwarf galaxy in a minor merger.
The X-ray actually formed when the IMBH tears apart a star which was moving close to it. This event was actually started in October 2003 and fading over the next decade. The distribution of photons and its relation to black hole mass helped them to calculate its size.
Intermediate-mass black holes are believed to be the key way to understand the evolution of black holes. There was a missing link between the stellar and supermassive black holes. After many studies, Scientists reached into a conclusion that there is an intermediate guy called IMBH. This IMBH is mysterious even in its Birth. There are 3 possible ways in which these black holes are formed.
The first possibility is that these Intermediate-mass black holes are formed when stellar-mass black holes and other Compact objects merged together by means of accretion.
The second possibility is the formation of IMBH by the collapse of Big giant stars which formed by the collision of massive stars. More intermediate-mass black holes are formed When stars in a cluster collide in a chain reaction. These many black holes then merged together to form the supermassive Black holes at the centre of the galaxy.
3rd possibility tells us about a hypothetical black hole which is formed soon after the big bang. This one is called the Primordial black holes. high densities and heterogeneous conditions could have led sufficiently dense regions to undergo gravitational collapse, forming these black holes. So we also believe that Intermediate-mass black holes are Primordial black holes.
So it is necessary to know about the intermediate-mass black hole before we go to understand the big guy. I believe, it is as important as to watch Infinity War before the Endgame.
Many intermediate-mass black holes are still missing and believed to be in the vicinity of big galaxies in the universe. We can expect more in the coming future.
– Arun S
Courtesy: – NASA, ESA and D. Lin (University of New Hampshire), Wikipedia
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