A mysterious blast that perplexed the astronomers!

Earlier this year a mysterious white light was seen flashing through the sky. The Astronomers argued that it was a monster black hole that swallowed the passing by star shredding it into million pieces. Other astronomers exclaimed that there might be new black hole being born.

On last week 233rd conference held by AAS, astronomers met in Seattle, on stressed on the appearance of   unusual flash in the night sky, speckled all over the world, on June 16, 2018. For succeeding three days, something exploded and produced mysterious flashing light that could be 10 times brighter than that of explosion by typical supernova, or exploding star. The light spreads, illuminating the dark sky and then faded away, not long before this mysterious event became the most studied event in the history of astrology.

It is thought that this mysterious event occurred in our parallel galaxy star-forming galaxy known as CGCG 137-068. In the direction of our constellation Hercules, this galaxy is as far as 200 million light-years away. The blast is named as AT2018cow and is called out from its nickname “the Cow” as its official designation. Astronomer Ryan Chornock at Ohio University, who studied this event in depth passed a statement that:

“We knew right away that this source went from inactive to peak luminosity within just a few days. That was enough to get everybody excited, because it was so unusual and, by astronomical standards, it was very close by”.

Researchers have established two possible hypotheses of this occurred mysterious event which in Seattle at a board discussion on January 10, 2019. The two groups shared two different opinion on the origin of this “Cow”. The published papers of one group explained that Cow is actually a monstrous black hole that engulfed a star, shredding it into pieces illuminating light. The other published work of second group suggested that the luminating light indicated the birth of a black hole or a neutron star. If considering the second scenario, this discovery could indeed mark for a supernova.

However, which scenario is actual truth?

Mystery explosion AAT2018cow discovery
Image Credit: Stephen Smartt/ATLAS

Black Hole Shredding a passing by star?

Astronomers believe that a black hole has power to shred an evolving star known as a white dwarf into million pieces . Astronomers claims this event as tidal disruption, in this event one body’s gravity act upon another’s. This mechanism is same as the action of moon’s gravity on the earth tidal waves. NASA states that in the locality of a black hole gravity – the tidal pull is same as our moon’s pull but much more powerful. Such powerful pull can be monstrous, tearing the passing by star into stream or gas particles.

The research team used several data to support their claim such from infrared radiation to high-energy gamma rays, to NASA’s orbiting Swift Observatory and other observatories. Astronomer Amy Lien of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, supportive to this scenario said:

“We’ve never seen anything exactly like the Cow, which is very exciting. We think a tidal disruption created the quick, really unusual burst of light at the beginning of the event and best explains Swift’s multiwavelength observations as it faded over the next few months”.

Astronomers have calculated that mass for the black hole and expressed it to be 100,000 to 1 million times that of the sun. Paul Kuin at University College London leading this research further explained this scenario as “The Cow produced a large cloud of debris in a very short time. Shredding a bigger star to produce a cloud like this would take a bigger black hole, result in a slower brightness increase and take longer for the debris to be consumed”.

The astronomers further pointed out that it’s very unusual to see something of this large size outside of a galactic center and claimed that: “it’s possible the Cow occurred in a nearby satellite galaxy or a globular star cluster whose older stellar populations could have a higher proportion of white dwarfs than average galaxies”.

The second scenario: A new Black Hole or Neutron Star is Born?

The second team of scientists gathered the data of broader range of wavelengths for cow that, spanned from radio waves to gamma rays. The claimed data assures supernova is born out of the Cow and directs them to the birth of a black hole or neutron star. Astronomer Raffaella Margutti at Northwestern University described this scenario as

“We know from theory that black holes and neutron stars form when a star dies, but we’ve never seen them right after they are born. Never”.

Margutti’s team analyzed from the data available from NASA’s NuSTAR, ESA’s XMM-Newton and INTEGRALsatellites, and the National Science Foundation’s Very Large Array and proposed the born of new black hole. They explained that the luminating or flashing light from the Cow signaled birth of supernova and elliminating the X- that fell onto a compact object is from the gas radiating energy.

Astronomer Daniel Perley from Liverpool John Moores University in England favored this hypothesis and stated that: “The properties of the Cow strain nearly all models we have tried to devise to explain it”.

All these studies are enough to confirm that whatever this something may be, it has evolved from a very energetic yet an extremely dense shell of material similar to the explosion antecedent.

The astronomers studied the cow for half year to figure out its organ and are still perplexed on its origin, continuing their debate on its births.

AT2018cow – aka the Cow – erupted in or near a galaxy known as CGCG 137-068
Image Credit: Sloan Digital Sky Survey

What is it we can conclude about AT2018cow? simply known as Cow blasted in a nearby galaxy known as CGCG 137-068, which 200 million light-years away apart in the direction and constellation of Hercules.

Bottom line: Astronomers are in conflict over a mysterious flash observed in the night sky in June 2018. They named it as Cow. One group of astronomers claims that it was a monstrous black hole tearing apart a passing star. Others argue the birth of a black-hole.

Source: An embedded X-ray source shines through the aspherical AT2018cow: revealing the inner workings of the most luminous fast-evolving optical transients

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