  Following our discovery of radio pulsations from the newly recognized
Anomalous X-ray Pulsar (AXP) 1E 1547.0-5408, we initiated X-ray monitoring with
the Swift X-ray Telescope, and obtained a single target-of-opportunity
observation with the Newton X-ray Multi-Mirror Mission (XMM-Newton). In
comparison with its historic minimum flux of 3e-13 ergs cm^-2 s^-1, the source
was found to be in a record high state, f_X(1-8 keV) = 5e-12 ergs cm^-2 s^-1,
or L_X = 1.7e35(d/9 kpc)^2 ergs s^-1, and declining by 25% in 1 month.
Extrapolating the decay, we bound the total energy in this outburst to 1e42 < E
< 1e43 ergs. The spectra (fitted with a Comptonized blackbody) show that an
increase in the temperature and area of a hot region, to 0.5 keV and ~16% of
the surface area of the neutron star, respectively, are primarily responsible
for its increase in luminosity. The energy, spectrum, and timescale of decay
are consistent with a deep crustal heating event, similar to an interpretation
of the X-ray turn-on of the transient AXP XTE J1810-197. Simultaneous with the
4.6 hour XMM-Newton observation, we observed at 6.4 GHz with the Parkes
telescope, measuring the phase relationship of the radio and X-ray pulse. The
X-ray pulsed fraction of 1E 1547.0-5408 is only ~7%, while its radio pulse is
relatively broad for such a slow pulsar, which may indicate a nearly aligned
rotator. As also inferred from the transient behavior of XTE J1810-197, the
only other AXP known to emit in the radio, the magnetic field rearrangement
responsible for this X-ray outburst of 1E 1547.0-5408 is probably the cause of
its radio turn-on.
