SCUBA and Spitzer observations of the Taurus molecular cloud - pulling the bull's tail

We present continuum data from the Submillimetre Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (JCMT), and the multiband imaging Photometer for Spitzer (MIPS) on the Spitzer Space Telescope, at submillimetre and infrared wavelengths, respectively. We study the Taurus molecular cloud 1 (TMC1) and, in particular, the region of the Taurus Molecular Ring (TMR). In the continuum data, we see no real evidence for a ring, but rather we see one side of it only, appearing as a filament. We name the filament ‘the bull's tail’. The filament is seen in emission at 850, 450 and 160 μm, and in absorption at 70 μm. We compare the data with archive data from the Infrared Astronomical Satellite (IRAS) at 12, 25, 60, 100 μm, in which the filament is also seen in absorption. We find that the emission from the filament consists of two components: a narrow, cold (∼8 K), central core, and a broader, slightly warmer (∼12 K), shoulder of emission. We use a radiative transfer code to model the filament's appearance, either in emission or absorption, simultaneously at each of the different wavelengths. Our best-fitting model uses a Plummer-like density profile and a homogeneous interstellar dust grain population. Unlike previous work on a similar, but different filament in Taurus, we require no grain coagulation to explain our data.