The search for the largest black hole in the universe took us to unimaginable scales for the human mind, but if you're wondering about the latest scientific news about these cosmic titans... we have one surrounded by rings of cosmic dust. Thanks to the records from the Chandra and Swift observatories of NASA, today we can appreciate a fabulous group of rings surrounding the black hole in the V404 Cygni system, located about 7,800 light-years from Earth.
What exactly do we know about V404 Cygni? Its general characteristics reveal a binary configuration with a giant star of 0.6-0.7 solar masses, and a black hole of 9 solar masses. Due to the proximity between the two, the star loses mass, which accumulates in an accretion disk and is eventually devoured by the black hole. The 'V' in its name confirms that it is a variable star, changing its brightness over time.
Light Echoes: The Dust Rings of the Black Hole in V404 Cygni
V404 Cygni had its moment of fame in June 2015, when it became the point of origin for an X-ray outburst recorded by NASA's Neil Gehrels Swift Observatory and the Pennsylvania State University. That event gave rise to a special phenomenon described by NASA as "light echoes." To better understand this phenomenon, the agency used an excellent example: Instead of having sound waves bouncing off the walls of a canyon, light echoes are produced when X-rays bounce off dust clouds between V404 Cygni and Earth.
Composite images result from combining X-rays detected by the Chandra observatory (in light blue) and optical information from the Pan-STARRS telescope in Hawaii. The team analyzed a total of 50 observations made by Swift between June 30 and August 25, 2015, while Chandra studied the system between July 11 and 25 of the same year. The event was so bright that Chandra's operators decided to place V404 Cygni "between detectors" to avoid damage.
What do these rings teach us? Besides revealing the behavior of the black hole, they also help us understand the "landscape" between V404 Cygni and Earth. The light echoes are thin and not wide, because the X-ray event lasted relatively little time. Another very important fact is the composition of those dust clouds, calculated from the absorbed energy levels. The team believes the dust contains a mixture of graphite and silicate grains, and that its density is not uniform in all directions.
Access the images: Click here
Sources: NASA, Slashgear
