The finding has been obtained thanks to observations with the OSIRIS instrument of the Gran Telescopio Canarias.
SPAIN – A team of researchers from the Institute of Institute of Astrophysics of the Canary Islands have observed for the first time by the Gran Telescopio Canarias (GTC), a wind of neutral material around a black hole, V404 Cygni, according to a study published in journal Nature.
This black hole is part of a binary system in the constellation Cygnus, about 8,000 light-years away. It is one of the closest to Earth and has a large accretion disk-about 10 million kilometers of radio, which makes its eruptions are extremely bright in all spectral ranges: X rays, visible emission, infrared and radio waves.
On June 15, 2015, the black hole V404 Cygni erupted after more than 25 years of inactivity. During this period its brightness increased a million times in a few days, becoming the brightest source of X-ray sky.
During the two weeks of the eruption, the GTC of 10.4 meters, made spectroscopic observations using a program specifically designed for this type of event.
Almost a year later, the investigations have revealed the presence of a wind-hydrogen and helium neutral material not ionized formed in the outer layers of the accretion disk. A phenomenon that regulates the process of ‘swallowed’ material by the black hole and to estimate the amount of mass ejected into the interstellar medium.
“We believe that what we have observed in V404 Cygni happens, at least in other black holes with accretion disks large,” concluded Jorge Casares, one of the discoverers of this black hole in 1992.
This wind moves at high speed 3000 kilometers per second to escape the gravitational field of the black hole. Their presence helps explain why the eruption, despite being light and very violent with constant changes of brightness and coronal mass ejections, was also very briefly.
Wind to feed the hole
“The eruption of V404 Cygni, by its complexity and the large number and quality of observations obtained, will help us understand how black holes ‘swallow’ matter through their accretion disks,” explains Teo Muñoz Darias, Institute of Institute of Astrophysics of the Canary Islands researcher and one of the authors of the study.
The V404 Cygni belongs to a type of system, of which less than 50 are known in which a black hole, of ten times the mass of the Sun, devours material from a nearby star, the star companion.
During this process, the material falls into the black hole, forming an accretion disk that emits X-rays in their internal and hottest areas. In outer areas, however, it can be studied this disc with visible light. This part of the spectrum is working in the GTC.
The research team consists of astrophysicists Institute of Institute of Astrophysics of the Canary Islands, the Universities of Oxford and Southampton in the UK, and research institutes in Germany, France and Japan.
In addition to the data obtained by the GTC, the work has included both X-ray observations by INTEGRAL and Swift satellites, such as the AMI radio interferometer in UK.
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