relatively simple and known to fit the observations reasonably well. $$\phi(\theta) = \frac{a}{4\pi}\frac{(1-g^2)}{[1+g^2-2g\cos(\theta)]^{1.5}}$$ where *a* and *g* are the albedo and phase function asymmetry factor of dust grains, respectively, and $\theta$ is the scattering angle measured from the direction of the incident photon. The simulation code adopted the peeling-off method [@yus84]: while each photon experiences multiple scatterings in random directions as it propagates through the dust cloud, the code keeps track of the fraction of a photon in the direction toward the Sun from each scattering, which is summed up for the final intensity. The Monte Carlo simulation code is described in more detail in @seo09 and Seon et al. (2012, to be submitted).

We took a 400 pc $\times$ 400 pc $\times$ 800 pc rectangular box as a simulation domain, with 800 pc chosen to be the distance to the rear face from the Sun in view of the size of the OES region whose distance is known to be $\sim$155 pc at the near-side and $\sim$586 pc at the far-side. The central axis was chosen along the line of sight toward the center of OES, ($\alpha$, $\delta$) = (60$^\circ$, -5$^\circ$), with the Sun placed at the center of 