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

TL;DR

This study uses XMM-Newton, Chandra, and CGPS data to analyze two faint supernova remnants, determining their properties, distances, and ruling out associated neutron stars, thereby enhancing understanding of their physical characteristics.

Contribution

The paper provides the first detailed X-ray analysis of SNRs G85.4+0.7 and G85.9-0.6, including morphology, spectroscopy, and distance estimates, with no associated neutron stars identified.

Findings

Distances: 3.5 and 4.8 kpc for the SNRs.

Temperatures: ~12-13 MK and ~15-19 MK.

No neutron star counterparts found.

Abstract

We present an XMM-Newton detection of two low radio surface brightness 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 HI 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 x 10^33 D(3.5)^2 erg/s (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 x 10^34 D(4.8)^2 erg/s (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.