The nature of the soft X-ray source in DG Tau

TL;DR

This paper investigates the spatial separation of soft and hard X-ray emissions in DG Tau, revealing that the soft X-ray source coincides with optical emission regions, indicating a shared physical origin.

Contribution

It demonstrates the spatial offset between soft and hard X-ray components in DG Tau using Chandra data, confirming the offset is physical and correlates with optical emission peaks.

Findings

Soft and hard X-ray components are spatially separated by ~0.2 arcsec.

The soft X-ray emission peak coincides with optical emission lines.

The spatial offset is confirmed to be physical, not instrumental.

Abstract

The classical T Tauri star DG Tau shows all typical signatures of X-ray activity and, in particular, harbors a resolved X-ray jet. We demonstrate that its soft and hard X-ray components are separated spatially by approximately 0.2 arcsec by deriving the spatial offset between both components from the event centroids of the soft and hard photons utilizing the intrinsic energy-resolution of the Chandra ACIS-S detector. We also demonstrate that this offset is physical and cannot be attributed to an instrumental origin or to low counting statistics. Furthermore, the location of the derived soft X-ray emission peak coincides with emission peaks observed for optical emission lines, suggesting that both, soft X-rays and optical emission, have the same physical origin.