Determining the Morphology of IRAS 08740-4243 for Calibration of BLAST

While we know that magnetic fields are important in star formation, how they alter from clouds down to disks has yet to be well determined. Knowing how the morphology of these fields changes is imperative to understanding their influence on important processes such as mass accretion, winds, and planet formation. BLAST-TNG is a balloon-borne telescope, launched from Antarctica, that seeks to probe magnetic fields at these intermediate size scales. In order to accurately do so, it is necessary to obtain multi-band observations of the main calibration source of BLAST-TNG, IRAS 087040-4243, to determine the shape of the beam. SOFIA is the only telescope that can do this, as its resolution is slightly better than the best resolution of BLAST-TNG (19'' vs 22''), and its polarization properties are well-known. It also offers wavelength coverage (Band E is 214 μm) that is close to BLAST's (shortest observing wavelength is 250 μm). Obtaining total intensity and polarimetric observations of IRAS 087040-4243 using Bands D and E will be critical for constraining our point spread function, as well as calibrating any off-axis instrument polarization.