Poster Presentation

Possible ALMA Counterpart of FRB 121102

Author(s): Keng-Wei Wu (NTHU), Tomotsugu Goto(NTHU), Tetsuya Hashinoto(NCHU)

Presenter: Keng-Wei Wu (NTHU)

Fast radio bursts (FRBs) are millisecond transients of unknown origins, most of which are
occurring at cosmological distances. Detecting their sub-mm counterparts is crucial to better
understand the origin of FRBs. However, no sub-mm counterpart has been reported up to
date. Here, we report possible brightening events of FRB121102, a repeating FRB which is
hosted by a star-forming dwarf galaxy at z = 0.193. Two brightening events were marginally
detected with ALMA Band 3 (∼ 100 GHz) at the position of the host galaxy within ∼1 hour
during its active phase. The flux densities of these sub-mm brightening events are ∼ 0.1-0.2
mJy, which are comparable to the prediction from magnetosphere models if the time scale of
the sb-mm counterparts is about 1 min. Furthermore, the cadence of the sub-mm detection
events is lower than that of FRBs in its active phase, being qualitatively consistent with the
magnetosphere models. Also, no radio observation of FRB121102 has been reported during
the time of this ALMA observation. If the sub-mm brightening events are indeed simultaneous
counterparts of FRBs, this would be the first detection of such case, which is a major step
forward in constraining the origins and physical mechanisms of FRBs.