Low particle acceleration found with MAGIC during the microquasars V404 Cygni flare

What is it about?

A MAGIC paper reporting the results of the low-mass microquasar V404 Cygni has been published in Monthly Notices of the Royal Astronomical Society (MNRAS). This system is composed of a star that orbits with a black hole of around 10 times the mass of our Sun. The compactness of the binary system and the gravitational attraction of the black hole pulls a stream of mass out from the companion star, producing an accretion disk around the black hole and a jet. V404 Cygni underwent exceptional X-ray outbursts in June 2015 after more than 25 years in quiescent state. The flaring was observed by many instruments, including MAGIC, providing extensive multi-wavelength coverage from radio to gamma rays ( see https://www.nasa.gov/…/nasa-missions-monitor-a-waking-black…"). The paper is posted as https://arxiv.org/abs/1707.00887.

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Why is it important?

The MAGIC non-detection sets an upper limit on the very-high-energy gamma-ray emission, above 200 GeV. Considering the gamma-ray opacity during the flare, MAGIC results point to a low particle acceleration rate inside the microquasar's relativistic radio jets.

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