Back to Volume
Paper: ALMA and VLA Measurements of Frequency-Dependent Time Lags in Sagittarius A*: Evidence for a Relativistic Outflow
Volume: 499, Revolution in Astronomy with ALMA: The Third Year
Page: 167
Authors: Brinkerink, C. D.
Abstract: Using ALMA and the VLA, we have measured simultaneous light curves of Sgr A* across a broad frequency range to constrain the speed of the radio-emitting plasma in the vicinity of the black hole. We detected and fit the maxima of an observed minor flare where flux density varied by ∼10%. The fitted times at frequencies from 100 GHz to 19 GHz reveal a simple frequency-dependent time lag relation where maxima at higher frequencies lead those at lower frequencies. Using the size-frequency relation of Sgr A*, these time lags suggest a moderately relativistic (lower estimates: 0.5c for two-sided, 0.77c for one-sided) collimated outflow.
Back to Volume