deletions | additions       diff --git a/Scientific Justification.tex b/Scientific Justification.tex  index fff2173..611fd45 100644  --- a/Scientific Justification.tex  +++ b/Scientific Justification.tex 
...
\section{Scientific Justification}  The Herschel observations of nearby molecular clouds find ubiquitous filamentary morphology of dust emission projected on the plane of sky. Although the ubiquity suggests that the filamentary morphology of projected emission is the result of filamentary structures in the 3D space, the spatial structure in the line of sight dimension of a single filament is rarely examined. While a direct measurement is impossible, {\bf  the line of sight ``thickness'' can be deduced from the dependence of molecular line emission on the volume density density}  and {\bf  the dependence of the Spectral Correlation Function on the spatial scales of self-similarity. self-similarity}.  \subsection{Line of sight ``thickness'' measured by cyano-molecules}  Molecular transitions of cyano-molecules are sensitive to the local volume density. The ratio of emission from a higher transition to that from a lower transition is characterized by a sharp transition as a function of volume density (Fig. ?; Green \& Chapman 1978, Wernli et al. 2007). By measuring multiple transition of cyanoacetylene (HC_3N), Avery et al. (1982) and Schloerb et al. (1983) were able to derive a volume density for the TMC-1 region, and thus the line of sight ``thickness'' of the region by comparing to the column density measurements. Li et al. (2012) applied the same method to the Taurus B213 filament (Li et al. 2012) with HC_3N (4-3) and (10-9) transitions. The result in B213 successfully re-confirms that B213 is a cylindrical filament (Hacar et al. 2013) and has a ``thickness'' of 0.12 pc in the line of sight direction. This result also conforms with the width in the plane of sky of \~ 0.1 pc, as derived from the density profile across the filament (Herschel ref?).