Where is SGR 1806−20?

Abstract

We apply a statistical method to derive very precise locations for soft gamma repeaters using data from the interplanetary network. We demonstrate the validity of the method by deriving a 600 arcsec2 error ellipse for SGR 1900+ 14 whose center agrees well with the VLA source position. We then apply it to SGR 1806-20, for which we obtain a 230 arcsec2 error ellipse, the smallest burst error box to date. We find that the most likely position of the source has a small but significant displacement from that of the nonthermal core of the radio supernova remnant G 10.0-0.3, which was previously thought to be the position of the repeater. We propose a different model to explain the changing supernova remnant morphology and the positions of the luminous blue variable and the bursting source.