WIDGET: System Performance and GRB Prompt Optical Observations

Abstract

The WIDeField telescope for Gamma-ray burst Early Timing (WIDGET) is used for a fully automated, ultra-wide-field survey aimed at detecting the prompt optical emission associated with Gamma-ray Bursts (GRBs). WIDGET surveys the HETE-2 and Swift/BAT pointing directions covering a total field of view of 62 degree x 62 degree every 10 secounds using an unfiltered system. This monitoring survey allows exploration of the optical emission before the gamma-ray trigger. The unfiltered magnitude is well converted to the SDSS r' system at a 0.1 mag level. Since 2004, WIDGET has made a total of ten simultaneous and one pre-trigger GRB observations. The efficiency of synchronized observation with HETE-2 is four times better than that of Swift. There has been no bright optical emission similar to that from GRB 080319B. The statistical analysis implies that GRB080319B is a rare event. This paper summarizes the design and operation of the WIDGET system and the simultaneous GRB observations obtained with this instrument.

19 pages, 11 figures, Accepted to appear in PASJ

References in corpus (8)

• Observations of the Naked-Eye GRB 080319B: Implications of Nature's Brightest Explosion
• Energy input and response from prompt and early optical afterglow emission in gamma-ray bursts
• Prior Emission Model for X-ray Plateau Phase of Gamma-Ray Burst Afterglows
• Calibrated griz magnitudes of Tycho stars: All-sky photometric calibration using bright stars
• Multi-color Shallow Decay and Chromatic Breaks in the GRB 050319 Optical Afterglow
• Extensive multiband study of the X-ray rich GRB 050408. A likely off-axis event with an intense energy injection
• Testing the External Shock Model of Gamma-Ray Bursts using the Late-Time Simultaneous Optical and X-ray Afterglows
• Prompt optical observations of GRBs with "Pi of the Sky" system

Cited by in corpus (4)

• Bulk Lorentz factors of Gamma-Ray Bursts
• A new era of sub-millimeter GRB afterglow follow-ups with the Greenland Telescope
• The Optical Luminosity Function of Gamma-ray Bursts deduced from ROTSE-III Observations
• Delayed Onset and Fast Rise of Prompt Optical-UV Emission from Gamma-Ray Bursts in Molecular Clouds