  We present XMM-Newton observations of the dusty Wolf-Rayet star WR 48a. This
is the first detection of this object in X-rays. The XMM-Newton EPIC spectra
are heavily absorbed and the presence of numerous strong emission lines
indicates a thermal origin of the WR 48a X-ray emission, with dominant
temperature components at kT_cool approx. 1 keV and kT_hot approx. 3~keV, the
hotter component dominating the observed flux. No significant X-ray variability
was detected on time scales < 1 day. Although the distance to WR 48a is
uncertain, if it is physically associated with the open clusters Danks 1 and 2
at d ~ 4 kpc, then the resultant X-ray luminosity L_X ~ 10^(35) ergs/s makes it
the most X-ray luminous Wolf-Rayet star in the Galaxy detected so far, after
the black-hole candidate Cyg X-3. We assume the following scenarios as the most
likely explanation for the X-ray properties of WR 48a: (1) colliding stellar
winds in a wide WR+O binary system, or in a hierarchical triple system with
non-degenerate stellar components; (2) accretion shocks from the WR 48a wind
onto a close companion (possibly a neutron star). More specific information
about WR48a and its wind properties will be needed to distinguish between the
above possibilities.
