2014MNRAS.438.1081X

GSH 90-28-17 is a high-latitude Galactic Hi supershell, identified in the Hi supershell catalogues with a velocity vlsr ∼ -17 km/s. We used the new Galactic Arecibo L-band Feed Array (GALFA) Hi survey data, which have much higher resolution and sensitivity than was previously available, to re-examine the properties of the supershell. We derived a new distance of 400 pc for GSH 90-28-17 and suggested that it is related to the Lac OB1 association. The radius of GSH 90-28-17 is 66.0±3.5 pc. The Hi mass of the shell is (3.1±0.1)x10⁴ M_☉. It has an age of ∼ 4.5 Myr and a total kinetic energy of (8.2±0.3)x10⁴⁸ erg. We extracted radio continuum data for the GSH 90-28-17 region from the 408-MHz All-Sky Survey and Bonn 1420-MHz survey and filtered the diffuse background Galactic emission. A radio loop-like ridge is found to be associated with the Hi shell at both frequencies and shows a non-thermal origin, with a temperature-temperature (TT)-plot index of α = -1.35±0.69. In addition, the pulsar J2307+2225, with a similar distance, is found in the shell region. We conclude that GSH 90-28-17 is probably an old, type II supernova remnant in the solar neighbourhood.