The First X-Ray Proper-Motion Measurements of the Forward Shock in the Northeastern Limb of SN 1006

TL;DR

This study presents the first X-ray proper-motion measurements of the forward shock in SN 1006's northeastern limb, confirming shock velocity and expansion consistent with models and previous radio data.

Contribution

It provides the first X-ray proper-motion measurement of SN 1006's forward shock, aligning with radio observations and offering insights into the remnant's expansion and ambient density.

Findings

Proper motion of 0.48 arcsec/yr measured.

Expansion index of ~0.54 consistent with supernova models.

Estimated ambient density of ~0.085/cm^3.

Abstract

We report on the first X-ray proper-motion measurements of the nonthermally-dominated forward shock in the northeastern limb of SN 1006, based on two Chandra observations taken in 2000 and 2008. We find that the proper motion of the forward shock is about 0.48 arcsec/yr and does not vary around the rim within the ~10% measurement uncertainties. The proper motion measured is consistent with that determined by the previous radio observations. The mean expansion index of the forward shock is calculated to be ~0.54 which matches the value expected based on an evolutionary model of a Type Ia supernova with either a power-law or an exponential ejecta density profile. Assuming pressure equilibrium around the periphery from the thermally-dominated northwestern rim to the nonthermally-dominated northeastern rim, we estimate the ambient density to the northeast of SN 1006 to be about 0.085/cm^3.