  Suzaku deep observations have discovered two highly significant nonthermal
X-ray sources, Suzaku J1804$-$2142 (Src 1) and Suzaku J1804$-$2140 (Src 2),
positionally coincident with the unidentified TeV $\gamma$-ray source, HESS
J1804$-$216. The X-ray sources are not time variable and show no counterpart in
other wavebands, except for the TeV source. Src 1 is unresolved at Suzaku
spatial resolution, whereas Src 2 is extended or composed of multiple sources.
The X-ray spectra are highly absorbed, hard, and featureless, and are well
fitted by absorbed power-law models with best-fit photon indices and absorption
columns of $-0.3_{-0.5}^{+0.5}$ and $0.2_{-0.2}^{+2.0}\times 10^{22}$ cm$^{-2}$
for Src 1, and $1.7_{-1.0}^{+1.4}$ and $1.1_{-0.6}^{+1.0}\times 10^{23}$
cm$^{-2}$ for Src 2. The measured X-ray absorption to the latter source is
significantly larger than the total Galactic neutral hydrogen column in that
direction. The unabsorbed 2--10 keV band luminosities are $7.5\times
10^{32}(d/{\rm 5 kpc})^2$ ergs s$^{-1}$ (Src 1) and $1.3\times 10^{33}(d/{\rm 5
kpc})^2$ ergs s$^{-1}$ (Src 2), where $d$ is the source distance. Among the
handful of TeV sources with known X-ray counterparts, HESS J1804$-$216 has the
largest ratio of TeV $\gamma$-ray to hard X-ray fluxes. We discuss the nature
of the emission and propose the Suzaku sources as plausible counterparts to the
TeV source, although further observations are necessary to confirm this.

Astrophysics