GRB 060505 was a 4-second May 2006 long gamma-ray burst (LGRB).
It stimulated research and analysis because such LGRBs are theorized
to be generated by core collapse supernovae, and though a host
galaxy was discovered (2dFGRS S173Z112, with
redshift 0.089), it had no such supernova. Among the possibilities
considered is the GRB came from core collapse that did not
produce a supernova, or that the GRB was from somewhere far beyond
the galaxy.
GRB 060505 is classified as a LGRB, being more than 2 seconds in length.
However, LGRBs average around 30 seconds, making GRB 060505 a short LGRB.
The term short gamma-ray burst (SGRB) is used for GRBs of less than 2 seconds.