Measuring fundamental jet properties with multiwavelength fast timing of the black hole X-ray binary MAXI J1820+070

A. J. Tetarenko, P. Casella, J. C.A. Miller-Jones, G. R. Sivakoff, J. A. Paice, F. M. Vincentelli, T. J. Maccarone, P. Gandhi, V. S. Dhillon, T. R. Marsh, T. D. Russell, P. Uttley

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


We present multiwavelength fast timing observations of the black hole X-ray binary MAXI J1820+070 (ASASSN-18ey), taken with the Karl G. Jansky Very Large Array (VLA), Atacama Large Millimeter/Sub-Millimeter Array (ALMA), Very Large Telescope (VLT), New Technology Telescope (NTT), Neutron Star Interior Composition Explorer (NICER), and XMM-Newton. Our data set simultaneously samples 10 different electromagnetic bands (radio - X-ray) over a 7-h period during the hard state of the 2018-2019 outburst. The emission we observe is highly variable, displaying multiple rapid flaring episodes. To characterize the variability properties in our data, we implemented a combination of cross-correlation and Fourier analyses. We find that the emission is highly correlated between different bands, measuring time-lags ranging from hundreds of milliseconds between the X-ray/optical bands to minutes between the radio/sub-mm bands. Our Fourier analysis also revealed, for the first time in a black hole X-ray binary, an evolving power spectral shape with electromagnetic frequency. Through modelling these variability properties, we find that MAXI J1820+070 launches a highly relativistic (Gamma =6.81 +1.06 -1.15}$) and confined (phi =0.45 +0.13 -0.11 deg) jet, which is carrying a significant amount of power away from the system (equivalent to sim 0.6 , L-{1-100{rm keV}). We additionally place constraints on the jet composition and magnetic field strength in the innermost jet base region. Overall, this work demonstrates that time-domain analysis is a powerful diagnostic tool for probing jet physics, where we can accurately measure jet properties with time-domain measurements alone.

Original languageEnglish
Pages (from-to)3862-3883
Number of pages22
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
StatePublished - Jul 1 2021


  • ASASSN-18ey
  • ISM: jets and outflows
  • X-rays: binaries
  • black hole physics
  • radio continuum: stars
  • stars: individual: MAXI J1820+070
  • submillimetre: stars


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