Two new Perseus arm supernova remnants discovered in the Canadian Galactic Plane Survey

Abstract

We report the discovery of two new second-quadrant supernova remnants, G96.0+2.0 and G113.0+0.2, in the data of the Canadian Galactic Plane Survey. The two SNRs are residents of the Perseus spiral arm at distances of 4.0 kpc and 3.1 kpc, respectively. The distances were determined kinematically by associating the objects with neutral hydrogen and molecular material. G96.0+2.0 is most likely located at the edge of a large stellar wind bubble with a systemic velocity of about −44 km s −1 . It consists of a relatively bright shell where the shock is encountering the wall of H i and slowly fades away towards the interior of the stellar wind bubble. The visible part of the remnant has a diameter of about 30 pc and a radio spectral index of α ≈− 0.66 (S ∼ ν α ), indicating that it is a shell-type remnant in an early stage of development. The SNR is most likely the remnant of a type Ib/c supernova explosion. G113.0+0.2 is located in an area of confusing thermal emission not far from the radio-bright supernova remnant Cassiopeia A. It has an unusual elongated structure consisting of a long polarized filament and a more complex head structure that is interacting with a small molecular cloud; it resides in a butterfly-shaped H i cavity, probably a stellar wind bubble. It is about 36 pc long and 15 pc wide at a position angle of 70 ◦ with the Galactic Plane. A pulsar with a relatively low period derivative, giving it a characteristic age of 10 million years, is located close to the centre of the radio continuum emission at a Perseus arm distance. Whether the pulsar is the result of the same supernova explosion that created G113.0+0.2 or if it was left behind by an earlier supernova that also shaped the stellar wind bubble remains uncertain.