The recurrent nova T Pyx underwent its sixth historical outburst in 2011, and
became the subject of an intensive multi-wavelength observational campaign. We
analyze data from the Swift and Suzaku satellites to produce a detailed X-ray
light curve augmented by epochs of spectral information. X-ray observations
yield mostly non-detections in the first four months of outburst, but both a
super-soft and hard X-ray component rise rapidly after Day 115. The super-soft
X-ray component, attributable to the photosphere of the nuclear-burning white
dwarf, is relatively cool (~45 eV) and implies that the white dwarf in T Pyx is
significantly below the Chandrasekhar mass (~1 M_sun). The late turn-on time of
the super-soft component yields a large nova ejecta mass (>~10^-5 M_sun),
consistent with estimates at other wavelengths. The hard X-ray component is
well fit by a ~1 keV thermal plasma, and is attributed to shocks internal to
the 2011 nova ejecta. The presence of a strong oxygen line in this thermal
plasma on Day 194 requires a significantly super-solar abundance of oxygen and
implies that the ejecta are polluted by white dwarf material. The X-ray light
curve can be explained by a dual-phase ejection, with a significant delay
between the first and second ejection phases, and the second ejection finally
released two months after outburst. A delayed ejection is consistent with
optical and radio observations of T Pyx, but the physical mechanism producing
such a delay remains a mystery.Comment: Re-submitted to ApJ after revision
