  Dihadron angular correlations in $d$+Au collisions at $\sqrt{s_{\rm NN}}=200$
GeV are reported as a function of the measured zero-degree calorimeter neutral
energy and the forward charged hadron multiplicity in the Au-beam direction. A
finite correlated yield is observed at large relative pseudorapidity
($\Delta\eta$) on the near side (i.e. relative azimuth $\Delta\phi\sim0$). This
correlated yield as a function of $\Delta\eta$ appears to scale with the
dominant, primarily jet-related, away-side ($\Delta\phi\sim\pi$) yield. The
Fourier coefficients of the $\Delta\phi$ correlation, $V_{n}=\langle\cos
n\Delta\phi\rangle$, have a strong $\Delta\eta$ dependence. In addition, it is
found that $V_{1}$ is approximately inversely proportional to the mid-rapidity
event multiplicity, while $V_{2}$ is independent of it with similar magnitude
in the forward ($d$-going) and backward (Au-going) directions.
