  In recent years a number of surveys and telescopes have observed the
plane-of-sky component of magnetic fields associated with molecular clouds.
However, observations of their line-of-sight magnetic field remain limited. To
address this issue, Tahani et al. (2018) developed a technique based on Faraday
rotation. The technique incorporates an ON-OFF approach to identify the
rotation measure induced by the magnetic fields associated with the cloud. The
upcoming abundance of Faraday rotation observations from the Square Kilometer
Array and its pathfinders necessitates robustly-tested software to
automatically obtain line-of-sight magnetic fields of molecular clouds. We
developed software, called MC-BLOS (Molecular Cloud Line-of-Sight Magnetic
Field), to carry out the technique in an automated manner. The software's input
are Faraday rotation of point sources (extra-galactic sources or pulsars),
extinction or column density maps, chemical evolution code results, and a
text/CSV file, which allows the user to specify the cloud name or other
parameters pertaining to the technique. For each cloud, the software invokes a
set of predefined initial parameters such as density, temperature, and
surrounding boundary, which the user can modify. The software then runs the
technique automatically, outputting line-of-sight magnetic field maps and
tables (including uncertainties) at the end of the process. This automated
approach significantly reduces analysis time compared to manual methods. We
have tested the software on previously-published clouds, and the results are
consistent within the reported uncertainty range. This software will facilitate
the analysis of forthcoming Faraday rotation observations, enabling a better
understanding of the role of magnetic fields in molecular cloud dynamics and
star formation.
