XMM-Newton, Chandra, and CGPS observations of the Supernova Remnants G85.4+0.7 and G85.9-0.6

Abstract

We present an XMM-Newton detection of two low radio surface brightness supernova remnants (SNRs), G85.4+0.7 and G85.9-0.6, discovered with the Canadian Galactic Plane Survey (CGPS). High-resolution XMM-Newton images revealing the morphology of the diffuse emission, as well as discrete point sources, are presented and correlated with radio and Chandra images. The new data also permit a spectroscopic analysis of the diffuse emission regions, and a spectroscopic and timing analysis of the point sources. Distances have been determined from H I and CO data to be 3.5 +/- 1.0 kpc for SNR G85.4+0.7 and 4.8 +/- 1.6 kpc for SNR G85.9-0.6. The SNR G85.4+0.7 is found to have a temperature of ~12-13 MK and a 0.5-2.5 keV luminosity of ~(1-4) × 10³³D²_3.5 erg s^-1 (where D_3.5 is the distance in units of 3.5 kpc), with an electron density n_e of ~(0.07-0.16) (fD_3.5)^-1/2 cm^-3 (where f is the volume filling factor) and a shock age of ~(9-49) (fD_3.5)^1/2 kyr. The SNR G85.9-0.6 is found to have a temperature of ~15-19 MK and a 0.5-2.5 keV luminosity of ~(1-4) × 10³⁴D²_4.8 erg s^-1 (where D_4.8 is the distance in units of 4.8 kpc), with an electron density n_e of ~(0.04-0.10) (fD_4.8)^-1/2 cm^-3 and a shock age of ~(12-42) (fD_4.8)^1/2 kyr. Based on the data presented here, none of the point sources appears to be the neutron star associated with either SNR.