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Updated: Oct 7, 2026

The Generation of Higher-order Laguerre-Gauss Optical Beams for High-precision Interferometry
Published on: August 12, 2013
Measuring the jet-black hole spin misalignment in MAXI J1820 + 070
Yuan Feng1, Ye-Fei Yuan1, Shuang-Nan Zhang2
1School of Astronomy and Space Science, University of Science and Technology of China, Hefei 230026, China; Department of Astronomy, University of Science and Technology of China, Hefei 230026, China.
Abstract:
Compact relativistic jets are commonly observed across multiple wavelengths during the hard-state outbursts of black hole X-ray binaries. If the axis of the jet is misaligned with the black hole spin, the jet will precess due to the effect of frame dragging of the spinning black hole. In this work, we present the first measurement of this jet-spin misalignment by modeling the phase-resolved spectra of X-ray quasi-periodic oscillations (QPOs) detected in MAXI J1820 + 070 during its hard state. We find the misalignment angle to be 30.3°-3.1°+3.2°, demonstrating significant evolution throughout the hard state, with the statistical significance much greater than 5σ. This result supports a geometric origin for QPOs within the black hole spacetime and provides direct observational evidence that the low-frequency QPOs (LFQPOs) in MAXI J1820 + 070 arise from jet precession. The measured large jet-spin misalignment provides geometric constraints on jet formation models, indicating that relativistic jets are launched in a highly non-axisymmetric environment. These findings offer valuable insights into refining theories of jet acceleration and magnetic field configuration near the event horizon.
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