FRB 20121102A was the first repeating fast radio burst ever discovered, shattering the theory that all FRBs are cataclysmic one-off events. Localized by the VLA to a low-mass, low-metallicity dwarf galaxy at z = 0.193, it exhibits one of the highest Faraday rotation measures ever observed (|RM| ~ 10^5 rad m⁻²), pointing to an environment near a massive black hole or dense supernova remnant.
| Observatory / Instrument | Spectral Regime | Observational Detection & Counterpart Findings |
|---|---|---|
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EVN (European VLBI)
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Radio VLBI
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Pinpointed burst position to < 12 milliarcseconds, coincident with persistent compact radio source.
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Gemini North
|
Optical (r-band)
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Identified host galaxy morphology and low-metallicity H II regions.
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Chandra / XMM-Newton
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X-ray
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Deep upper limits on persistent X-ray emission rule out super-Eddington accretion.
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