V404 Cygni tagged posts

A precise measurement of the magnetic field in the corona of the black hole binary V404 Cygni. Science, 2017; 358 (6368): 1299 http://science.sciencemag.org/content/358/6368/1299

Chris Packham, associate professor of physics and astronomy at The University of Texas at San Antonio (UTSA), has collaborated on a new study that expands the scientific community’s understanding of black holes in our galaxy and the magnetic fields that surround them. Packham and astronomers observed the magnetic field of a black hole within our own galaxy from multiple wavelengths for the first time.

Black holes usually form when a massive star explodes and the remnant core collapses under the force of intense gravity...

Artist’s impression of the V404 Cygni black hole jet. Credit: G Perez Diaz IAC

They are nature’s very own Death Star beams – ultra-powerful jets of energy that shoot out from the vicinity of black holes like deadly rays from the Star Wars super-weapon. Now a team of scientists led by the University of Southampton has moved a step closer to understanding these mysterious cosmic phenomena – known as relativistic jets – by measuring how quickly they ‘switch on’ and start shining brightly once they are launched.

How these jets form is still a puzzle. One theory suggests that they develop within the ‘accretion disc’...

an artistic view of the accretion disc surrounding the black hole V404 Cygni, where the intense wind detected by GTC becomes evident. Credit: Gabriel Pérez, SMM (IAC)

An international team of astrophysicists have detected an intense wind from one of the closest known black holes to the Earth. During observations of V404 Cygni, which went into a bright and violent outburst in June 2015 after more than 25 years of quiescence, the team began taking optical measurements of the black hole’s accretion disc using the 10.4m Gran Telescopio CANARIAS (GTC) – the biggest optical-infrared telescope in the world in the Roque de los Muchachos Observatory (Garafía, La Palma) in the Canary Islands.

The results show a wind of neutral material (unionised H and He), formed in the outer layers of the accret...

Image shows an artist’s impression of a black hole, similar to V404 Cyg, devouring material from an orbiting companion star. Credit: ESO/L. Calçada

Violent red flashes, lasting just fractions of a second, have been observed during one of the brightest black hole outbursts in recent years. June 2015, a black hole called V404 Cygni underwent dramatic brightening for about 2 weeks, as it devoured material that it had stripped off an orbiting companion star. V404 Cygni, which is ~7,800 light years from Earth, was the first definitive black hole to be identified in our Galaxy and can appear extremely bright when it is actively devouring material.

The astronomers associated the red colour with fast-moving jets of matter that were ejected from close to the black hole...