Hard X-ray and Infrared Emission from Apparently Single White Dwarfs

Y. -H. Chu; R. A. Gruendl; M. A. Guerrero; K. Y. -L. Su

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arXiv · astro-ph/0701025

Hard X-ray and Infrared Emission from Apparently Single White Dwarfs

Y. -H. Chu·R. A. Gruendl·M. A. Guerrero·K. Y. -L. Su

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Abstract

The photospheric emission of a white dwarf (WD) is not expected to be detectable in hard X-rays or the mid-IR. Hard X-ray (~1 keV) emission associated with a WD is usually attributed to a binary companion; however, emission at 1 keV has been detected from three WDs without companions: KPD 0005+5106, PG 1159, and WD 2226-210. The origin of their hard X-ray emission is unknown, although it has been suggested that WD 2226-210 has a late-type companion whose coronal activity is responsible for the hard X-rays. Recent Spitzer observations of WD 2226-210 revealed mid-IR excess emission indicative of the existence of a dust disk. It now becomes much less clear whether WD 2226-210's hard X-ray emission originates from the corona of a late-type companion or from the accretion of the disk material. High-quality X-ray observations and mid-IR observations of KPD 0005+5106 and PG 1159 are needed to help us understand the origin of their hard X-ray emission.

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BibTeX RIS

Y. -H. Chu, R. A. Gruendl, M. A. Guerrero, K. Y. -L. Su. 2007-01-01. Hard X-ray and Infrared Emission from Apparently Single White Dwarfs. https://arxiv.org/abs/astro-ph/0701025

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