Extremely Soft X-ray Flash as the indicator of off-axis orphan GRB afterglow

Yuji Urata, Kuiyun Huang, Ryo Yamazaki +1

We verified the off-axis jet model of X-ray flashes (XRFs) and examined a discovery of off-axis orphan gamma-ray burst (GRBs) afterglows. The XRF sample was selected on the basis o…