Dartmouth Events

Abstract: Since fast radio bursts (FRBs) are short in duration, and emit at long wavelengths, their signal is highly affected by propagation through ionised, magnetised and turbulent media. Inhomogeneities in the interstellar medium (ISM) scatter the radio waves in multiple directions, acting as astrophysical lenses. Constructive and destructive interference along these different paths causes intensity modulations, known as scintillation. Decoherence of the scintillation will occur if the source size is large with respect to the diffractive scale of the lens, resulting in reduced modulation of the intensity fluctuations. Therefore, the strength of the scintillation from media in the FRB galaxy can be used to constrain the size of the emission region. In this talk, I will present the discovery of two mutually coherent scintillation scales in FRB 20221022A's spectrum: one from the Milky Way ISM, and another from the local environment or host galaxy. I will present the first ever constraint of an FRB emission region size using scintillation, confirming that FRB 20221022A originates from within the magnetosphere of a compact object. For this FRB, we rule out emission models that operate at large radial distances. To conclude, I will elaborate on the potential for exploring the FRB emission physics and local environment properties using scintillation on a larger FRB sample in the future. 

Hosted by Professor Jens Mahlmann

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https://dartmouth.zoom.us/j/92751420885?pwd=QnIwN0RiSGkzMUtjQVZxRlZLMkcwQT09

Meeting ID: 927 5142 0885

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