Extraordinary multi-wavelength flaring of V404 Cygni
The extraordinary multi-wavelength flaring of V404 Cygni during
the 2015 outburst is presented for the first time with full radio
coverage from the Arcminute Microkelvin Imager (AMI) and the enhanced
Multi-Element Radio Linked Interferometer Network (e-MERLIN). The superb
X-ray coverage was provided by INTEGRAL. An estimated minimum of 250
powerful relativistic ejections were tracked during this period. For 86
individual ejection / particle acceleration events one was able to
measure the internal energy, physical size and magnetic field at the
point where the flare peaks to synchrotron self-absorption, the most
comprehensive study of the astrophysics of relativistic ejections to date.
For the first time a clear and near-linear flux-rms correlation in the
radio flux densities is reported. Modelling the multi-wavelength
coverage of the radio flares requires an extended phase of particle
acceleration in contrast to simple impulsive injection models. The
largest radio flare is preceded by a phase of optical oscillations and
followed one day later by a smaller but optically thin flare, likely due
to ejecta interacting with the interstellar medium. Comparing the radio
emission to contemporaneous X-ray (INTEGRAL/JEM-X and ISGRI) and optical
data, we find that the X-ray and radio measurements are correlated on
all timescales from seconds to one day. Correlation with the optical
flux densities is weak at short time scales, but becomes significant on
time scales greater than a few hours. If the total estimated kinetic
energy budget was deposited locally to the source, as implied by the
failure to detect jets on angular scales larger than milliarcsec (and
may be related to the strong and variable local absorption), then one
predicts that a nova-like shell could have been formed.
Credits:
"Comprehensive coverage of particle acceleration and kinetic feedback
from the stellar mass black hole V404 Cygni",
Fender, R.P.; Mooley, K.P.; Motta, S.E.; Bright, J.S.; Williams,
D.R.A.; Rushton, A.P.; Beswick, R.J.; Miller-Jones, J.C.A.; Kimura, M.;
Isogai, K.; Kato, T.
2022, MNRAS, in press
https://arxiv.org/abs/2206.09831
