An optical search for transients lasting a few seconds

TL;DR

This study used a high-cadence wide-field optical survey to search for short-duration transients, setting upper limits on their occurrence rate due to the absence of detections.

Contribution

It introduces a novel high-speed wide-field optical survey method capable of detecting transients lasting a few seconds, establishing constraints on their occurrence rates.

Findings

No transient sources detected in the survey.

Set upper limits on the rate of short-duration optical transients.

Demonstrated the effectiveness of high-cadence wide-field imaging for transient searches.

Abstract

Using a prototype of the Tomo-e Gozen wide-field CMOS mosaic camera, we acquire wide-field optical images at a cadence of 2 Hz and search them for transient sources of duration 1.5 to 11.5 seconds. Over the course of eight nights, our survey encompasses the equivalent of roughly two days on one square degree, to a fluence equivalent to a limiting magnitude about $V = 15.6$ in a 1-second exposure. After examining by eye the candidates identified by a software pipeline, we find no sources which meet all our criteria. We compute upper limits to the rate of optical transients consistent with our survey, and compare those to the rates expected and observed for representative sources of ephemeral optical light.