The Herschel and JCMT Gould Belt Surveys: Constraining Dust Properties in the Perseus B1 Clump With Pacs, Spire, and Scuba-2

Abstract

2in the Perseus molecular cloud. We determined the dust emissivity index using four different techniques to combine the Herschel PACS+SPIRE data at 160 − 500 µm with the SCUBA-2 data at 450 µm and 850 µm. Of our four techniques, we found the most robust method was to filter-out the large-scale emission in the Herschel bands to match the spatial scales recovered by the SCUBA-2 reduction pipeline. Using this method, we find β ≈ 2 towards the filament region and moderately dense material and lower β values (β 1.6) towards the dense protostellar cores, possibly due to dust grain growth. We find that β and temperature are more robust with the inclusion of the SCUBA-2 data, improving estimates from Herschel data alone by factors of ∼ 2 for β and by ∼ 40% for temperature. Furthermore, we find core mass differences of 30% compared to Herschel-only estimates with an adopted β = 2, highlighting the necessity of long wavelength submillimeter data for deriving accurate masses of prestellar and protostellar cores.1. We applied the colour correction factors in Table 1 to the Herschel bands.

The JCMT Gould Belt Survey: first results from the SCUBA-2 observations of the Ophiuchus molecular cloud and a virial analysis of its prestellar core population

“…SCUBA-2 450-µm flux densities have previously been seen to show an excess over the values predicted from interpolation of the Herschel 350-µm and 500-µm bands (Sadavoy et al 2013). This discrepancy was also seen in our data when they were brought to a common resolution using the published beam models.…”

“…In order to make SCUBA-2 and Herschel observations comparable, the large-scale structure must be removed from the Herschel observations. To accomplish this, the SCUBA-2 pipeline was applied to the Herschel observations following the method described by Sadavoy et al (2013), in which the Herschel data are added to the SCUBA-2 bolometer time series, and the reduction process, as described in Section 2.1, is repeated, including the application of the mask shown in Figure A5 to the Herschel data. The original SCUBA-2 reduction of the data is then subtracted from the Herschel +SCUBA-2 map, leaving the spatially-filtered Herschel signal.…”

Far-infrared/submillimetre properties of pre-stellar cores L1521E, L1521F and L1689B as revealed by theHerschelSPIRE instrument – I. Central positions

“…We use the dust opacity law from Hildebrand (1983) to be consistent with other papers on dense cores (e.g. André et al 2010;Sadavoy et al 2013). However, recent results from dust models have shown that κ 1000 can vary by up to a factor of 2.0 (e.g.…”

Alma Resolves the Torus of NGC 1068: Continuum and Molecular Line Emission

“…This imaging covered 50 square degrees of nearby clouds within the Gould Belt, including well-known regions such as Auriga (Broekhoven-Fiene et al 2016), Ophiuchus (Pattle et al 2015), Orion (Salji et al 2015a(Salji et al , 2015bKirk et al 2016aKirk et al , 2016bLane et al 2016;Mairs et al 2016), Perseus (Hatchell et al 2013;Sadavoy et al 2013;Chen et al 2016), SerpensMWC297 (Rumble et al 2015), Taurus (Buckle et al 2015;Ward-Thompson et al 2016), and W40 (Rumble et al 2016). Among these targets, the GBS survey covered approximately 2.5 square degrees of the IC 5146 starforming region.…”

“…The 12 CO = -J 3 2 ( ) emission line lies within the SCUBA-2 850 μm bandpass, and can therefore "contaminate" the thermal dust emission measured (Johnstone et al 2003;Drabek et al 2012). Previous observations suggest that the amount of CO contamination is generally small, typically less than 20% (Johnstone et al 2003;Drabek et al 2012;Hatchell et al 2013;Sadavoy et al 2013;Buckle et al 2015;Pattle et al 2015;Salji et al 2015a;Coudé et al 2016;Kirk et al 2016a), though in zones with weak 850 μm emission and a strong CO outflow, CO has been observed to contribute up to 90% of the flux.…”