An extremely soft and weak fast X-ray transient associated with a luminous supernova

W. -X. Li, Z. -P. Zhu, X. -Z. Zou +101

Long gamma-ray bursts (LGRBs), including their subclasses of low-luminosity GRBs (LL-GRBs) and X-ray flashes (XRFs) characterized by low spectral peak energies, are known to be ass…