Reliability of Radio Transients Detected in the Nasu Sky Survey

This article reports on the reliability of 11 radio transients detected in the Nasu sky survey. We derived false detection rates and evaluated the statistical significance of each transient source. A single source, labeled WJN J1443+3439, was statistically significant at the 10(-5) significance level; the other 10 sources were insignificant. On the basis of this single detection, the sky surface density of live radio transients was estimated to be 2(-1.9)(+9) x 10(-6) deg(-2) at a flux density above 3 Jy and a frequency of 1.42 GHz. Since this result is comparable with other survey results and known transients, WJN J1443+3439 could not be excluded. The sky surface density supported a power-law distribution of source count versus flux density. For transient events, the power-law exponent was approximately -3/2. These results are expected to assist radio variable/transient surveys in next-generation facilities such as the Square Kilometre Array.