deletions | additions       diff --git a/sectionMethdology_To.tex b/sectionMethdology_To.tex  index 3924426..452dc6d 100644  --- a/sectionMethdology_To.tex  +++ b/sectionMethdology_To.tex 
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Regardless of this initial visual inspection, the true nature of these filaments, and their association with a spiral feature, can only be established by looking at radial velocity data. The filament must have similar line-of-sight velocities along its length. Moreover, the measured radial velocities should be very close to those predicted by the Milky Way's rotation curve for arms at a known distance. To investigate the velocity structure of these fifteen filaments, we employ radial velocity data from four separate radio surveys: HOPS \citep{Purcell_2012,Walsh_2011}, MALT90 \citep{Foster_2011,Jackson_2013}, BGPS \citep{Schlingman_2011} and GRS \citep{Jackson_2006}. The HOPS, MALT90, and BGPS surveys are all geared towards probing dense regions hosting the early stages of high mass star formation. From the HOPS survey, we utilize the thermal line from ammonia. With a critical density of about $10^{4}\textrm{ cm}^{-3}$, ammonia traces dense molecular gas and is often found in dense, cool clouds with temperatures less than 100 K \citep{Purcell_2012}. The $\mathrm{N_2H^{+}}$ and $\textrm{HCO}^{+}$ thermal line we utilize from the MALT90 and BGPS surveys are also particularly strong in cold dense regions. While the HOPS and BGPS surveys are complete over 100 and 170 square degrees, respectively, MALT90 was a follow-up survey targeted towards $\approx2000$ dense molecular clumps first identified in the ATLASGAL 870 $\mu\textrm{m}$ Galactic plane survey \citep{Schuller_2009}. As infrared dark clouds tend to harbor cool, high density clumps of gas which fuel the formation of massive stars, all three of these databases contain spectra for hundreds of regions within the longitude range of the potential bone-like filaments.  In cases where HOPS, MALT90, and BGPS catalog data are not available along the extinction feature, we were also able to extract spectra from GRS (high resolution $^{13}$CO (1-0) data) and MALT90 p-p-v cubes using the spectrum extracter tool in Glue. A demonstration of the procedure used to extract velocities in Glue is shown in figure \ref{fig:glue}. As CO traces lower density gas (on average $10^2 \textrm{ cm}^{-3}$) and $\mathrm{N_2H+}$, $\textrm{HCO}^+$, and $\textrm{NH}_3$ trace high density gas ($>10^4 \textrm{ cm}^{-3}$), the dense gas sources provide much stronger evidence for the velocity of cold, dense, filamentary IRDCs. When dense gas sources were not available, the complete and unbiased high resolution GRS survey, although less desirable, allows us to roughly gauge the velocity along entire lengths of filaments. In filaments composed entirely of GRS spectra, we took HOPS spectra over the entire filament using Glue and confirmed that this HOPS-determined velocity agreed with GRS-determined average velocity to within 5 km/s.In the future, we hope to take higher resolution spectra of high density tracers to better pinpoint the velocity of these IRDCs.  By overlaying the HOPS, MALT90, BGPS, and GRS determined velocities on a p-v diagram of CO emission, we determine whether these filaments are physical spines or simply a chance projection of mid-infrared extinction features along our line-of-sight. For this study, we use the whole-galaxy \citet{Dame_2001} CO survey to locate each of the arms in p-p-v space. Of the approximately fifteen candidates identified visually, ten of these candidates are within 10 km/s of the Scutum-Centaurus and Norma-Cygnus arms. The central coordinates for these ten filaments, along with their average lengths, LSR velocities, and distances, are listed in figure \ref{fig:candidates}. We plot these ten candidates in p-p-v space, as shown in figure \ref{fig:skeleton}. In addition to showing our Bone candidates, we show several different predictions of the positions of two spiral arms toward the inner Galaxy in longitude-velocity space, from \citet{Dame_2011}, \citet{Sanna_2014}, \citet{Shane_1972}, and \citet{Vallee_2008}. For reference, we note that the new BeSSeL (maser) results from \citet{Sato_2014} in the first quadrant favor the oldest, HI-based \citet{Shane_1972}, fits for the Scutum arm.   After narrowing down our list to ten filaments with kinematic structure consistent with Galactic rotation, we develop a set of quantitative criteria for objects to be called "bones:"