A Question of Mass: Accounting for all the Dust in the Crab Nebula with the Deepest Far Infrared Maps

Supernovae represent significant sources of dust in the interstellar medium. In this work, deep far-infrared (FIR) observations of the Crab Nebula are studied to provide a new and reliable constraint on the amount of dust present in this supernova remnant. Deep exposures between 70 and 500 $\mu$m taken by PACS and SPIRE instruments on-board the Herschel Space Telescope, compiling all observations of the nebula including PACS observing mode calibration, are refined using advanced processing techniques, thus providing the most accurate data ever generated by Herschel on the object. We carefully find the intrinsic flux of each image by masking the source and creating a 2D polynomial fit to deduce the background emission. After subtracting the estimated non-thermal synchrotron component, two modified blackbodies were found to best fit the remaining infrared continuum, the cold component with T$_c$ = 8.3 $\pm$ 3.0 K and M$_d$ = 0.27 $\pm$ 0.05 M$_{\odot}$ and the warmer component with T$_w$ = 27.2 $\pm$ 1.3 K and M$_d$ = (1.3 $\pm$ 0.4) $\times$10$^{-3}$ M$_{\odot}$.