deletions | additions       diff --git a/using_rotation_curves.tex b/using_rotation_curves.tex  index d5ce0a1..a0c9c59 100644  --- a/using_rotation_curves.tex  +++ b/using_rotation_curves.tex 
...
\subsection{Using Rotation Curves and Velocity Measurements to Place Nessie in 3D}  Ever since velocity-resolved observations of stars and gas have been possible, astronomers have been modeling the rotation pattern of the Milky Way. Using a measured rotation curve for the Milky Way's gas, \citep[e.g.][ ]{McClureGriffiths2007}, one can translate observed LSR velocities to a unique distance in the Outer Galaxy, and to one of two possible (``Near" or ``Far") distances toward the Inner Galaxy. Figure \ref{fig:topview} shows iso-$v_{LSR}$ contours toward the Inner Galaxy, around the longitude range of Nessie, superimposed on the data-driven cartoon of our current understanding of the Milky Way's structure. As Figure \ref{fig:topview} shows, Notice that  velocities associated with the near-side of the Scutum-Centaurus Arm in Nessie's longitude range should be near 40 km\ s$^{-1}$. Combining the a  modern measurements of estimate for  the Sun's height above the plane ($z\sim ($z_{\rm Sun}\sim  25$ pc), with the IAU galactic Galactic  coordinate definitions as described in Figure \ref{fig:topview}, definitions,  we can determine where the physical  mid-Plane of the Galaxy should \textit{should}  appear in the $(l^{II}, b^{II})$ system at any particular distance from the Sun. Sun (cf. Figure \ref {fig:xx}).  Figure \ref{fig:coloredlines} shows where the Scutum-Centaurus Arm would appear on the Sky (for a distance to SrgA* of 8.5 kpc, a rotation speed for the Milky Way of 220 km\ s$^{-1}$, and (U,V,W) motion for the Sun of 11.1, 12.4, and 7.2 km\ s$^{-1}$, respectively). As its caption explains in detail, Figure \ref{fig:coloredlines}'s colored lines are associated with the near part of the Scutum-Centaurus Arm (shown as short, yellow-greeen line segment in Figure \ref{fig:topview}; note the different color schemes, chosen to emphasize different velocity ranges, in Figures \ref{fig:topview} and \ref{fig:coloredlines}). Arm.  The dashed colored line in Figure \ref{fig:coloredlines}, indicating the predicted position of the Galactic Plane on the Sky at the distance to the near side of the Scutum-Centaurus Arm, passes almost directly through Nessie. Solid colored lines show 20 pc above and below the Plane at the distance to the Scutum-Centaurus Arm, so Figure \ref{fig:coloredlines} makes it is very clear that Nessie lies within just a few pc of the Plane, along its entire length. This is either an extremely fortuitous coincidence, or an indication that Nessie is tracing a significant feature that effectively marks the mean location of the Galactic Plane. Given the waviness of the plane on 10 pc scales (see above, \citep{Malhotra1994}), the location at even less than 10 pc from the mean plane is likely fortuitous--but the location so close to the mean is not.