deletions | additions       diff --git a/section_Description_of_the_data__.tex b/section_Description_of_the_data__.tex  index def075c..ec58c98 100644  --- a/section_Description_of_the_data__.tex  +++ b/section_Description_of_the_data__.tex 
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This project uses observations made by ALMA under project 2012.1.00762.S proposed by Hirota et al. We used the Quality Assurance, step 2 data (QA2) downloaded from the Japanese Virtual Observatory site, which images the CO(1-0) line at $1.34\times 0.83$ arcsec resolution, corresponding to $29\times 18$ pc at the 4.5 Mpc distance of M83 \citep{Thim_2003}. The imaged data cube has a velocity resolution of 2.57 km~s$^{-1}$. With a median brightness sensitivity of $\sigma=0.89$~K per beam, the data set are ideally suited for the identification and decomposition of GMCs \citep{Rosolowsky_2006}. Through this analysis, we adopt a CO-to-H$_2$ conversion factor of X$_{\mathrm{CO}} = 2\times 10^{20}$~(K~km~s$^{-1}$)$^{-1}$~cm$^{-2}$ \cite{Bolatto_2013}. With this conversion factor, the data cube has a $1\sigma$ mass surface density sensitivity of 9.9 $M_{\odot}~\mathrm{pc}^{-2}$ and a per-beam mass sensitivity of $6\times 10^3~M_{\odot}$.   Since the Quality Assurance data delivered as part of the project do not include total power or short spacing data, the resulting image is affected by some negative artifacts from when the cleaning process applied to the interferometer maps. These artifacts are most noticeable noticable  toward the bright emission in the nucleus of the galaxy. These artifacts The data  are driven by also likely  missing flux from large-scale, large scale,  diffuse CO  emission components \citep[e.g.,][]{Pety_2013} and sidelobes around bright sources. The data show no evidence for bad calibration and, apart \citep[e.g.,][]{Pety_2013}. Apart  fromthe effects of  spatial filtering, filtering effects,  the data are of high quality (Figure \ref{fig:tmax}). The data and  arenonetheless  well-suited for the task at hand, namely identifying the GMCs in hand. The spatial scales to which ALMA is sensitive (20 pc to 200 pc) are well matched to  the galaxy as bright scales of  compact features in the CO molecular cloud  emission and then characterizing their properties. the spatial filtering eliminates the diffuse gas that is not associated with the compact star forming clouds.