Fumihiko Usui

About

Fumihiko Usui is an observational astrophysicist specializing in gamma-ray burst (GRB) afterglow studies and robotic telescope systems for rapid transient detection. His research focuses on capturing early-time optical emission from GRBs, a critical window for understanding progenitor environments and jet physics. Usui’s major contributions include the development and operation of the WIDGET (Wide-Field Telescope for GRB Early Timing) robotic system, which autonomously monitors the HETE-2 satellite’s field-of-view to detect optical flashes coincident with or preceding GRB triggers. This innovative approach enables the study of prompt optical emission and potential precursor activity. His most cited work, “A Multiband Study of the Optically Dark GRB 051028” (10 citations), exemplifies his method: combining data from the Lulin 1.0m telescope and WIDGET to characterize an optically faint burst, revealing dust extinction as the cause of its darkness. Though his citation counts are modest, Usui’s technical achievements—designing a wide-field (62°×62°) robotic imager covering ~80% of HETE-2’s field—represent a significant engineering contribution to time-domain astronomy. His work bridges the gap between satellite triggers and ground-based follow-up, enabling the earliest possible optical observations of cosmic explosions.

Research Focus

Key Achievements

Top Papers

1. 1
   A Multiband Study of the Optically Dark GRB 051028

   10 citations · 2007
2. 2
   The search for optical emission on and before the GRB trigger with the WIDGET telescope

   4 citations · 2005

Key Collaborators

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