Why do some intermediate polars show soft X-ray emission? A survey of XMM-Newton spectra
P. A. Evans
C. Hellier
2381/18859
https://figshare.le.ac.uk/articles/journal_contribution/Why_do_some_intermediate_polars_show_soft_X-ray_emission_A_survey_of_XMM-Newton_spectra/10113773
We make a systematic analysis of the XMM-Newton X-ray spectra of intermediate polars (IPs) and find that, contrary to the traditional picture, most show a soft blackbody component. We compare the results with those from AM Her stars and deduce that the blackbody emission arises from reprocessing of hard X-rays, rather than from the blobby accretion sometimes seen in AM Hers. Whether an IP shows a blackbody component appears to depend primarily on geometric factors: a blackbody is not seen in those that have accretion footprints that are always obscured by accretion curtains or are only visible when foreshortened on the white-dwarf limb. Thus we argue against previous suggestions that the blackbody emission characterizes a separate subgroup of IPs that are more akin to AM Hers, and develop a unified picture of the blackbody emission in these stars.
2012-10-24 09:06:04
Science & Technology
Physical Sciences
Astronomy & Astrophysics
accretion
accretion disks
novae
cataclysmic variables
X-rays : binaries
MAGNETIC CATACLYSMIC VARIABLES
ACCRETING WHITE-DWARF
SPIN PULSE
ROSAT OBSERVATIONS
FO-AQUARII
AO PISCIUM
GK-PERSEI
PQ GEM
MASS
EXCESS