XMM-Newton Detection of X-ray Emission from the Metal-Polluted White Dwarf G 29-38

TL;DR

This study confirms X-ray emission from the metal-polluted white dwarf G 29-38, likely due to debris accretion, using archival XMM-Newton data that supports previous Chandra findings and suggests possible iron line emission.

Contribution

Reanalysis of archival XMM-Newton data to confirm X-ray emission from G 29-38 and distinguish it from nearby sources, supporting debris accretion as the emission origin.

Findings

X-ray emission from G 29-38 is confirmed with consistent luminosities.

Spectral analysis suggests the presence of an iron emission line.

Proper motion analysis supports the association of X-ray emission with G 29-38.

Abstract

A recent analysis of Chandra X-ray data of the metal-polluted white dwarf (WD) G29-38 has revealed X-ray emission that can be attributed to the accretion of debris from a planetary body. In the light of this detection we revisit here archival XMM-Newton observations of G29-38 from which only an upper limit was derived in the past due to the presence of a relatively bright nearby X-ray source. An analysis of these data in multiple energy bands allows disentangling the X-ray emission at the location of G29-38 from that of the nearby source. The similar spectral properties of the source in the XMM-Newton and Chandra observations and their spatial shift, consistent with the proper motion of G29-38 between these observations, strengthen the origin of that X-ray emission from G29-38. The X-ray luminosities from both observations are consistent within 1-$\sigma$ uncertainties, so too are the best-fit plasma temperatures. Although the count number is small, there is tantalizing evidence for line emission in the 0.7-0.8 keV energy band from an optically-thin hot plasma. The most likely candidate for this line emission would be the Fe complex at 16 \r{A}.