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151. The Herschel and JCMT Gould Belt Surveys: constraining dust properties in the Perseus B1 clump with PACS, SPIRE, and SCUBA-2

Author

Sadavoy, S. I., Di Francesco, J., Johnstone, D., Currie, M. J., Drabek, E., Hatchell, J., Nutter, D., André, Ph., Arzoumanian, D., Benedettini, M., Bernard, J.-P., Duarte-Cabral, A., Fallscheer, C., Friesen, R., Greaves, J., Hennemann, M., Hill, T., Jenness, T., Könyves, V., Matthews, B., Mottram, J. C., Pezzuto, S., Roy, A., Rygl, K., Schneider-Bontemps, N., Spinoglio, L., Testi, L., Tothill, N., Ward-Thompson, D., White, G., Sadavoy, S. I., Di Francesco, J., Johnstone, D., Currie, M. J., Drabek, E., Hatchell, J., Nutter, D., André, Ph., Arzoumanian, D., Benedettini, M., Bernard, J.-P., Duarte-Cabral, A., Fallscheer, C., Friesen, R., Greaves, J., Hennemann, M., Hill, T., Jenness, T., Könyves, V., Matthews, B., Mottram, J. C., Pezzuto, S., Roy, A., Rygl, K., Schneider-Bontemps, N., Spinoglio, L., Testi, L., Tothill, N., Ward-Thompson, D., and White, G.

Abstract

We present Herschel observations from the Herschel Gould Belt Survey and SCUBA-2 science verification observations from the JCMT Gould Belt Survey of the B1 clump in 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 that the most robust method was filtering 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 toward the filament region and moderately dense material and lower β values (β >~ 1.6) toward 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.

152. The JCMT Gould Belt Survey: evidence for radiative heating and contamination in the W40 complex

Author

Rumble, D., Hatchell, J., Pattle, K., Kirk, H., Wilson, T., Buckle, J., Berry, D.S., Broekhoven-Fiene, H., Currie, M.J., Fich, M., Jenness, T., Johnstone, D., Mottram, J. C., Nutter, D., Pineda, J.E., Quinn, C., Salji, C., Tisi, S., Walker-Smith, S., Di Francesco, J., Hogerheijde, M.R., Ward-Thompson, D., Bastien, P., Bresnahan, D., Butner, H., Chen, M., Chrysostomou, A., Coude, S., Davis, C.J., Drabek-Maunder, E., Duarte-Cabral, A., Fiege, J., Friberg, P., Friesen, R., Fuller, G.A., Graves, S., Greaves, J., Gregson, J., Holland, W., Joncas, G., Kirk, J. M., Knee, L. B. G., Mairs, S., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Mowat, C., Rawlings, J., Richer, J., Robertson, D., Rosolowsky, E., Sadavoy, S., Thomas, H., Tothill, N., Viti, S., White, G. J., Wouterloot, J., Yates, J., Zhu, M., Rumble, D., Hatchell, J., Pattle, K., Kirk, H., Wilson, T., Buckle, J., Berry, D.S., Broekhoven-Fiene, H., Currie, M.J., Fich, M., Jenness, T., Johnstone, D., Mottram, J. C., Nutter, D., Pineda, J.E., Quinn, C., Salji, C., Tisi, S., Walker-Smith, S., Di Francesco, J., Hogerheijde, M.R., Ward-Thompson, D., Bastien, P., Bresnahan, D., Butner, H., Chen, M., Chrysostomou, A., Coude, S., Davis, C.J., Drabek-Maunder, E., Duarte-Cabral, A., Fiege, J., Friberg, P., Friesen, R., Fuller, G.A., Graves, S., Greaves, J., Gregson, J., Holland, W., Joncas, G., Kirk, J. M., Knee, L. B. G., Mairs, S., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Mowat, C., Rawlings, J., Richer, J., Robertson, D., Rosolowsky, E., Sadavoy, S., Thomas, H., Tothill, N., Viti, S., White, G. J., Wouterloot, J., Yates, J., and Zhu, M.

Abstract

We present SCUBA-2 450 μm and 850 μm observations of the W40 complex in the Serpens-Aquila region as part of the James Clerk Maxwell Telescope (JCMT) Gould Belt Survey (GBS) of nearby star-forming regions. We investigate radiative heating by constructing temperature maps from the ratio of SCUBA-2 fluxes using a fixed dust opacity spectral index, β = 1.8, and a beam convolution kernel to achieve a common 14.8 arcsec resolution. We identify 82 clumps ranging between 10 and 36 K with a mean temperature of 20 ± 3 K. Clump temperature is strongly correlated with proximity to the external OB association and there is no evidence that the embedded protostars significantly heat the dust. We identify 31 clumps that have cores with densities greater than 105cm-3. 13 of these cores contain embedded Class 0/I protostars. Many cores are associated with bright-rimmed clouds seen in Herschel 70 μm images. From JCMT HARP observations of the 12CO 3-2 line, we find contamination of the 850 μm band of up to 20 per cent. We investigate the free-free contribution to SCUBA-2 bands from large-scale and ultracompact HII regions using archival VLA data and find the contribution is limited to individual stars, accounting for 9 per cent of flux per beam at 450 μm or 12 per cent at 850 μm in these cases. We conclude that radiative heating has potentially influenced the formation of stars in the Dust Arc sub-region, favouring Jeans stable clouds in the warm east and fragmentation in the cool west.

153. The JCMT and Herschel Gould Belt Surveys: a comparison of SCUBA-2 and Herschel data of dense cores in the Taurus dark cloud L1495

Author

Ward-Thompson, D., Pattle, K., Kirk, J. M., Marsh, K., Buckle, J., Hatchell, J., Nutter, D. J., Griffin, M. J., Di Francesco, J., André, P., Beaulieu, S., Berry, D., Broekhoven-Fiene, H., Currie, M., Fich, M., Jenness, T., Johnstone, D., Kirk, H., Mottram, J., Pineda, J., Quinn, C., Sadavoy, S., Salji, C., Tisi, S., Walker-Smith, S., White, G. J., Hill, T., Könyves, V., Palmeirim, P., Pezzuto, S., Ward-Thompson, D., Pattle, K., Kirk, J. M., Marsh, K., Buckle, J., Hatchell, J., Nutter, D. J., Griffin, M. J., Di Francesco, J., André, P., Beaulieu, S., Berry, D., Broekhoven-Fiene, H., Currie, M., Fich, M., Jenness, T., Johnstone, D., Kirk, H., Mottram, J., Pineda, J., Quinn, C., Sadavoy, S., Salji, C., Tisi, S., Walker-Smith, S., White, G. J., Hill, T., Könyves, V., Palmeirim, P., and Pezzuto, S.

Abstract

We present a comparison of Submillimetre Common User Bolometer Array-2 (SCUBA-2) 850-μm and Herschel 70-500-μm observations of the L1495 filament in the Taurus Molecular Cloud with the goal of characterizing the SCUBA-2 Gould Belt Survey (GBS) data set. We identify and characterize starless cores in three data sets: SCUBA-2 850-μm, Herschel 250-μm, and Herschel 250-μm spatially filtered to mimic the SCUBA-2 data. SCUBA-2 detects only the highest-surface-brightness sources, principally detecting protostellar sources and starless cores embedded in filaments, while Herschel is sensitive to most of the cloud structure, including extended low-surface-brightness emission. Herschel detects considerably more sources than SCUBA-2 even after spatial filtering. We investigate which properties of a starless core detected by Herschel determine its detectability by SCUBA-2, and find that they are the core's temperature and column density (for given dust properties). For similar-temperature cores, such as those seen in L1495, the surface brightnesses of the cores are determined by their column densities, with the highest-column-density cores being detected by SCUBA-2. For roughly spherical geometries, column density corresponds to volume density, and so SCUBA-2 selects the densest cores from a population at a given temperature. This selection effect, which we quantify as a function of distance, makes SCUBA-2 ideal for identifying those cores in Herschel catalogues that are closest to forming stars. Our results can now be used by anyone wishing to use the SCUBA-2 GBS data set.

154. The JCMT Gould Belt Survey: a first look at Southern Orion A with SCUBA-2

Author

Mairs, S., Johnstone, D., Kirk, H., Buckle, J., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Graves, S., Hatchell, J., Jenness, T., Mottram, J. C., Nutter, D., Pattle, K., Pineda, J. E., Salji, C., Di Francesco, J., Hogerheijde, M. R., Ward-Thompson, D., Bastien, P., Bresnahan, D., Butner, H., Chen, M., Chrysostomou, A., Coudé, S., Davis, C. J., Drabek-Maunder, E., Duarte-Cabral, A., Fiege, J., Friberg, P., Friesen, R., Fuller, G. A., Greaves, J., Gregson, J., Holland, W., Joncas, G., Kirk, J. M., Knee, L. B. G., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Mowat, C., Rawlings, J., Richer, J., Robertson, D., Rosolowsky, E., Rumble, D., Sadavoy, S., Thomas, H., Tothill, N., Viti, S., White, G. J., Wouterloot, J., Yates, J., Zhu, M., Mairs, S., Johnstone, D., Kirk, H., Buckle, J., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Graves, S., Hatchell, J., Jenness, T., Mottram, J. C., Nutter, D., Pattle, K., Pineda, J. E., Salji, C., Di Francesco, J., Hogerheijde, M. R., Ward-Thompson, D., Bastien, P., Bresnahan, D., Butner, H., Chen, M., Chrysostomou, A., Coudé, S., Davis, C. J., Drabek-Maunder, E., Duarte-Cabral, A., Fiege, J., Friberg, P., Friesen, R., Fuller, G. A., Greaves, J., Gregson, J., Holland, W., Joncas, G., Kirk, J. M., Knee, L. B. G., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Mowat, C., Rawlings, J., Richer, J., Robertson, D., Rosolowsky, E., Rumble, D., Sadavoy, S., Thomas, H., Tothill, N., Viti, S., White, G. J., Wouterloot, J., Yates, J., and Zhu, M.

Abstract

We present the JCMT Gould Belt Survey's first look results of the southern extent of the Orion A Molecular Cloud (δ ≤ -5:31:27.5). Employing a two-step structure identification process, we construct individual catalogues for large-scale regions of significant emission labelled as islands and smaller-scale subregions called fragments using the 850 μm continuum maps obtained using SCUBA-2. We calculate object masses, sizes, column densities, and concentrations. We discuss fragmentation in terms of a Jeans instability analysis and highlight interesting structures as candidates for follow-up studies. Furthermore, we associate the detected emission with young stellar objects (YSOs) identified by Spitzer and Herschel. We find that although the population of active star-forming regions contains a wide variety of sizes and morphologies, there is a strong positive correlation between the concentration of an emission region and its calculated Jeans instability. There are, however, a number of highly unstable subregions in dense areas of the map that show no evidence of star formation. We find that only ˜72 per cent of the YSOs defined as Class 0+I and flat-spectrum protostars coincide with dense 850 μm emission structures (column densities >3.7 × 1021 cm-2). The remaining 28 per cent of these objects, which are expected to be embedded in dust and gas, may be misclassified. Finally, we suggest that there is an evolution in the velocity dispersion of YSOs such that sources which are more evolved are associated with higher velocities.

155. The JCMT Gould Belt Survey: evidence for dust grain evolution in Perseus star-forming clumps

Author

Chen, Michael Chun-Yuan, Di Francesco, J., Johnstone, D., Sadavoy, S., Hatchell, J., Mottram, J. C., Kirk, H., Buckle, J., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Jenness, T., Nutter, D., Pattle, K., Pineda, J. E., Quinn, C., Salji, C., Tisi, S., Hogerheijde, M. R., Ward-Thompson, D., Bastien, P., Bresnahan, D., Butner, H., Chrysostomou, A., Coude, S., Davis, C. J., Drabek-Maunder, E., Duarte-Cabral, A., Fiege, J., Friberg, P., Friesen, R., Fuller, G. A., Graves, S., Greaves, J., Gregson, J., Holland, W., Joncas, G., Kirk, J. M., Knee, L. B. G., Mairs, S., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Mowat, C., Pezzuto, S., Rawlings, J., Richer, J., Robertson, D., Rosolowsky, E., Rumble, D., Schneider-Bontemps, N., Thomas, H., Tothill, N., Viti, S., White, G. J., Wouterloot, J., Yates, J., Zhu, M., Chen, Michael Chun-Yuan, Di Francesco, J., Johnstone, D., Sadavoy, S., Hatchell, J., Mottram, J. C., Kirk, H., Buckle, J., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Jenness, T., Nutter, D., Pattle, K., Pineda, J. E., Quinn, C., Salji, C., Tisi, S., Hogerheijde, M. R., Ward-Thompson, D., Bastien, P., Bresnahan, D., Butner, H., Chrysostomou, A., Coude, S., Davis, C. J., Drabek-Maunder, E., Duarte-Cabral, A., Fiege, J., Friberg, P., Friesen, R., Fuller, G. A., Graves, S., Greaves, J., Gregson, J., Holland, W., Joncas, G., Kirk, J. M., Knee, L. B. G., Mairs, S., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Mowat, C., Pezzuto, S., Rawlings, J., Richer, J., Robertson, D., Rosolowsky, E., Rumble, D., Schneider-Bontemps, N., Thomas, H., Tothill, N., Viti, S., White, G. J., Wouterloot, J., Yates, J., and Zhu, M.

Abstract

The dust emissivity spectral index, β, is a critical parameter for deriving the mass and temperature of star-forming structures and, consequently, their gravitational stability. The β value is dependent on various dust grain properties, such as size, porosity, and surface composition, and is expected to vary as dust grains evolve. Here we present β, dust temperature, and optical depth maps of the star-forming clumps in the Perseus Molecular Cloud determined from fitting spectral energy distributions to combined Herschel and JCMT observations in the 160, 250, 350, 500, and 850 μm bands. Most of the derived β and dust temperature values fall within the ranges of 1.0-2.7 and 8-20 K, respectively. In Perseus, we find the β distribution differs significantly from clump to clump, indicative of grain growth. Furthermore, we also see significant localized β variations within individual clumps and find low-β regions correlate with local temperature peaks, hinting at the possible origins of low-β grains. Throughout Perseus, we also see indications of heating from B stars and embedded protostars, as well evidence of outflows shaping the local landscape.

156. The JCMT Gould Belt Survey: SCUBA-2 observations of circumstellar discs in L 1495

Author

Buckle, J. V., Drabek-Maunder, E., Greaves, J., Richer, J. S., Matthews, B. C., Johnstone, D., Kirk, H., Beaulieu, S. F., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Hatchell, J., Jenness, T., Mottram, J. C., Nutter, D., Pattle, K., Pineda, J. E., Salji, C., Tisi, S., Di Francesco, J., Hogerheijde, M. R., Ward-Thompson, D., Bastien, P., Butner, H., Chen, M., Chrysostomou, A., Coude, S., Davis, C. J., Duarte-Cabral, A., Friberg, P., Friesen, R., Fuller, G. A., Graves, S., Gregson, J., Holland, W., Joncas, G., Kirk, J. M., Knee, L. B. G., Mairs, S., Marsh, K., Moriarty-Schieven, G., Rawlings, J., Rosolowsky, E., Rumble, D., Sadavoy, S., Thomas, H., Tothill, N., Viti, S., White, G. J., Wilson, C. D., Wouterloot, J., Yates, J., Zhu, M., Buckle, J. V., Drabek-Maunder, E., Greaves, J., Richer, J. S., Matthews, B. C., Johnstone, D., Kirk, H., Beaulieu, S. F., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Hatchell, J., Jenness, T., Mottram, J. C., Nutter, D., Pattle, K., Pineda, J. E., Salji, C., Tisi, S., Di Francesco, J., Hogerheijde, M. R., Ward-Thompson, D., Bastien, P., Butner, H., Chen, M., Chrysostomou, A., Coude, S., Davis, C. J., Duarte-Cabral, A., Friberg, P., Friesen, R., Fuller, G. A., Graves, S., Gregson, J., Holland, W., Joncas, G., Kirk, J. M., Knee, L. B. G., Mairs, S., Marsh, K., Moriarty-Schieven, G., Rawlings, J., Rosolowsky, E., Rumble, D., Sadavoy, S., Thomas, H., Tothill, N., Viti, S., White, G. J., Wilson, C. D., Wouterloot, J., Yates, J., and Zhu, M.

Abstract

We present 850 and 450 μm data from the James Clerk Maxwell Telescope (JCMT) Gould Belt Survey obtained with Submillimetre Common-User Bolometer Array 2 (SCUBA-2) and characterize the dust attributes of Class I, Class II and Class III disc sources in L 1495. We detect 23 per cent of the sample at both wavelengths, with the detection rate decreasing through the Classes from I to III. The median disc mask is 1.6 × 10-3 M⊙, and only 7 per cent of Class II sources have disc masses larger than 20 Jupiter masses. We detect a higher proportion of discs towards sources with stellar hosts of spectral type K than spectral type M. Class II discs with single stellar hosts of spectral type K have higher masses than those of spectral type M, supporting the hypothesis that higher mass stars have more massive discs. Variations in disc masses calculated at the two wavelengths suggest that there may be differences in dust opacity and/or dust temperature between discs with hosts of spectral types K to those with spectral type M.

157. The JCMT Gould Belt survey: a first look at dense cores in Orion B

Author

Kirk, H., Francesco, J. Di, Johnstone, D., Duarte-Cabral, A., Sadavoy, S., Hatchell, J., Mottram, J. C., Buckle, J., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Jenness, T., Nutter, D., Pattle, K., Pineda, J. E., Quinn, C., Salji, C., Tisi, S., Hogerheijde, M. R., Ward-Thompson, D., Bastien, P., Bresnahan, D., Butner, H., Chen, M., Chrysostomou, A., Coude, S., Davis, C. J., Drabek-Maunder, E., Fiege, J., Friberg, P., Friesen, R., Fuller, G. A., Graves, S., Greaves, J., Gregson, J., Holland, W., Joncas, G., Kirk, J. M., Knee, L. B. G., Mairs, S., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Mowat, C., Rawlings, J., Richer, J., Robertson, D., Rosolowsky, E., Rumble, D., Thomas, H., Tothill, N., Viti, S., White, G. J., Wouterloot, J., Yates, J., Zhu, M., Kirk, H., Francesco, J. Di, Johnstone, D., Duarte-Cabral, A., Sadavoy, S., Hatchell, J., Mottram, J. C., Buckle, J., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Jenness, T., Nutter, D., Pattle, K., Pineda, J. E., Quinn, C., Salji, C., Tisi, S., Hogerheijde, M. R., Ward-Thompson, D., Bastien, P., Bresnahan, D., Butner, H., Chen, M., Chrysostomou, A., Coude, S., Davis, C. J., Drabek-Maunder, E., Fiege, J., Friberg, P., Friesen, R., Fuller, G. A., Graves, S., Greaves, J., Gregson, J., Holland, W., Joncas, G., Kirk, J. M., Knee, L. B. G., Mairs, S., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Mowat, C., Rawlings, J., Richer, J., Robertson, D., Rosolowsky, E., Rumble, D., Thomas, H., Tothill, N., Viti, S., White, G. J., Wouterloot, J., Yates, J., and Zhu, M.

Abstract

We present a first look at the SCUBA-2 observations of three sub-regions of the Orion B molecular cloud: LDN 1622, NGC 2023/2024, and NGC 2068/2071, from the JCMT Gould Belt Legacy Survey. We identify 29, 564, and 322 dense cores in L1622, NGC 2023/2024, and NGC 2068/2071 respectively, using the SCUBA-2 850 μm map, and present their basic properties, including their peak fluxes, total fluxes, and sizes, and an estimate of the corresponding 450 μm peak fluxes and total fluxes, using the FellWalker source extraction algorithm. Assuming a constant temperature of 20 K, the starless dense cores have a mass function similar to that found in previous dense core analyses, with a Salpeter-like slope at the high-mass end. The majority of cores appear stable to gravitational collapse when considering only thermal pressure; indeed, most of the cores which have masses above the thermal Jeans mass are already associated with at least one protostar. At higher cloud column densities, above 1–2 × 1023 cm−2, most of the mass is found within dense cores, while at lower cloud column densities, below 1 × 1023 cm−2, this fraction drops to 10% or lower. Overall, the fraction of dense cores associated with a protostar is quite small (<8%), but becomes larger for the densest and most centrally concentrated cores. NGC 2023/2024 and NGC 2068/2071 appear to be on the path to forming a significant number of stars in the future, while L1622 has little additional mass in dense cores to form many new stars.

158. First results from the Herschel Gould Belt Survey in Taurus

Author

Kirk, J. M., Ward-Thompson, D., Palmeirim, P., André, Ph., Griffin, M. J., Hargrave, P. J., Könyves, V., Bernard, J.- P., Nutter, D. J., Sibthorpe, B., Di Francesco, J., Abergel, A., Arzoumanian, D., Benedettini, M., Bontemps, S., Elia, D., Hennemann, M., Hill, T., Men'shchikov, A., Motte, F., Nguyen-Luong, Q., Peretto, N., Pezzuto, S., Rygl, K. L. J., Sadavoy, S. I., Schisano, E., Schneider, N., Testi, L., White, G., Kirk, J. M., Ward-Thompson, D., Palmeirim, P., André, Ph., Griffin, M. J., Hargrave, P. J., Könyves, V., Bernard, J.- P., Nutter, D. J., Sibthorpe, B., Di Francesco, J., Abergel, A., Arzoumanian, D., Benedettini, M., Bontemps, S., Elia, D., Hennemann, M., Hill, T., Men'shchikov, A., Motte, F., Nguyen-Luong, Q., Peretto, N., Pezzuto, S., Rygl, K. L. J., Sadavoy, S. I., Schisano, E., Schneider, N., Testi, L., and White, G.

Abstract

The whole of the Taurus region (a total area of 52 deg2) has been observed by the Herschel Spectral and Photometric Imaging Receiver (SPIRE) and Photodetector Array Camera and Spectrometer (PACS) instruments at wavelengths of 70, 160, 250, 350 and 500 μm as part of the Herschel Gould Belt Survey. In this paper we present the first results from the part of the Taurus region that includes the Barnard 18 and L1536 clouds. A new source-finding routine, the Cardiff Source-finding AlgoRithm (CSAR), is introduced, which is loosely based on CLUMPFIND, but that also generates a structure tree, or dendrogram, which can be used to interpret hierarchical clump structure in a complex region. Sources were extracted from the data using the hierarchical version of CSAR and plotted on a mass-size diagram. We found a hierarchy of objects with sizes in the range 0.024-2.7 pc. Previous studies showed that gravitationally bound prestellar cores and unbound starless clumps appeared in different places on the mass-size diagram. However, it was unclear whether this was due to a lack of instrumental dynamic range or whether they were actually two distinct populations. The excellent sensitivity of Herschel shows that our sources fill the gap in the mass-size plane between starless and pre-stellar cores, and gives the first clear supporting observational evidence for the theory that unbound clumps and (gravitationally bound) prestellar cores are all part of the same population, and hence presumably part of the same evolutionary sequence.

159. The JCMT Gould Belt Survey: first results from SCUBA-2 observations of the Cepheus Flare region

Author

Pattle, K., Ward-Thompson, D., Kirk, J. M., Di Francesco, J., Kirk, H., Mottram, J. C., Keown, J., Buckle, J., Beaulieu, S. F., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Hatchell, J., Jenness, T., Johnstone, D., Nutter, D., Pineda, J. E., Quinn, C., Salji, C., Tisi, S., Walker-Smith, S., Hogerheijde, M. R., Bastien, P., Bresnahan, D., Butner, H., Chen, M., Chrysostomou, A., Coudé, S., Davis, C. J., Drabek-Maunder, E., Duarte-Cabral, A., Fiege, J., Friberg, P., Friesen, R., Fuller, G. A., Graves, S., Greaves, J., Gregson, J., Holland, W., Joncas, G., Knee, L. B. G., Mairs, S., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Mowat, C., Rawlings, J., Richer, J., Robertson, D., Rosolowsky, E., Rumble, D., Sadavoy, S., Thomas, H., Tothill, N., Viti, S., White, G. J., Wouterloot, J., Yates, J., Zhu, M., Pattle, K., Ward-Thompson, D., Kirk, J. M., Di Francesco, J., Kirk, H., Mottram, J. C., Keown, J., Buckle, J., Beaulieu, S. F., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Hatchell, J., Jenness, T., Johnstone, D., Nutter, D., Pineda, J. E., Quinn, C., Salji, C., Tisi, S., Walker-Smith, S., Hogerheijde, M. R., Bastien, P., Bresnahan, D., Butner, H., Chen, M., Chrysostomou, A., Coudé, S., Davis, C. J., Drabek-Maunder, E., Duarte-Cabral, A., Fiege, J., Friberg, P., Friesen, R., Fuller, G. A., Graves, S., Greaves, J., Gregson, J., Holland, W., Joncas, G., Knee, L. B. G., Mairs, S., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Mowat, C., Rawlings, J., Richer, J., Robertson, D., Rosolowsky, E., Rumble, D., Sadavoy, S., Thomas, H., Tothill, N., Viti, S., White, G. J., Wouterloot, J., Yates, J., and Zhu, M.

Abstract

We present observations of the Cepheus Flare obtained as part of the James Clerk Maxwell Telescope (JCMT) Gould Belt Legacy Survey (GBLS) with the SCUBA-2 instrument. We produce a catalogue of sources found by SCUBA-2, and separate these into starless cores and protostars. We determine masses and densities for each of our sources, using source temperatures determined by the Herschel Gould Belt Survey. We compare the properties of starless cores in four different molecular clouds: L1147/58, L1172/74, L1251 and L1228. We find that the core mass functions for each region typically show shallower-than Salpeter behaviour. We find that L1147/58 and L1228 have a high ratio of starless cores to Class II protostars, while L1251 and L1174 have a low ratio, consistent with the latter regions being more active sites of current star formation, while the former are forming stars less actively.We determine that if modelled as thermally supported Bonnor–Ebert spheres, most of our cores have stable configurations accessible to them.We estimate the external pressures on our cores using archival 13CO velocity dispersion measurements and find that our cores are typically pressure confined, rather than gravitationally bound.We perform a virial analysis on our cores, and find that they typically cannot be supported against collapse by internal thermal energy alone, due primarily to the measured external pressures. This suggests that the dominant mode of internal support in starless cores in the Cepheus Flare is either non-thermal motions or internal magnetic fields.

160. 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

Author

Pattle, K., Ward-Thompson, D., Kirk, J. M., White, G. J., Drabek-Maunder, E., Buckle, J., Beaulieu, S. F., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Hatchell, J., Kirk, H., Jenness, T., Johnstone, D., Mottram, J. C., Nutter, D., Pineda, J. E., Quinn, C., Salji, C., Tisi, S., Walker-Smith, S., Di Francesco, J., Hogerheijde, M. R., André, Ph., Bastien, P., Bresnahan, D., Butner, H., Chen, M., Chrysostomou, A., Coude, S., Davis, C. J., Duarte-Cabral, A., Fiege, J., Friberg, P., Friesen, R., Fuller, G. A., Graves, S., Greaves, J., Gregson, J., Griffin, M. J., Holland, W., Joncas, G., Knee, L. B. G., Könyves, V., Mairs, S., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Rawlings, J., Richer, J., Robertson, D., Rosolowsky, E., Rumble, D., Sadavoy, S., Spinoglio, L., Thomas, H., Tothill, N., Viti, S., Wouterloot, J., Yates, J., Zhu, M., Pattle, K., Ward-Thompson, D., Kirk, J. M., White, G. J., Drabek-Maunder, E., Buckle, J., Beaulieu, S. F., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Hatchell, J., Kirk, H., Jenness, T., Johnstone, D., Mottram, J. C., Nutter, D., Pineda, J. E., Quinn, C., Salji, C., Tisi, S., Walker-Smith, S., Di Francesco, J., Hogerheijde, M. R., André, Ph., Bastien, P., Bresnahan, D., Butner, H., Chen, M., Chrysostomou, A., Coude, S., Davis, C. J., Duarte-Cabral, A., Fiege, J., Friberg, P., Friesen, R., Fuller, G. A., Graves, S., Greaves, J., Gregson, J., Griffin, M. J., Holland, W., Joncas, G., Knee, L. B. G., Könyves, V., Mairs, S., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Rawlings, J., Richer, J., Robertson, D., Rosolowsky, E., Rumble, D., Sadavoy, S., Spinoglio, L., Thomas, H., Tothill, N., Viti, S., Wouterloot, J., Yates, J., and Zhu, M.

Abstract

In this paper, we present the first observations of the Ophiuchus molecular cloud performed as part of the James Clerk Maxwell Telescope (JCMT) Gould Belt Survey (GBS) with the SCUBA-2 instrument. We demonstrate methods for combining these data with previous HARP CO, Herschel, and IRAM N2H+ observations in order to accurately quantify the properties of the SCUBA-2 sources in Ophiuchus. We produce a catalogue of all of the sources found by SCUBA-2. We separate these into protostars and starless cores. We list all of the starless cores and perform a full virial analysis, including external pressure. This is the first time that external pressure has been included in this level of detail. We find that the majority of our cores are either bound or virialized. Gravitational energy and external pressure are on average of a similar order of magnitude, but with some variation from region to region. We find that cores in the Oph A region are gravitationally bound prestellar cores, while cores in the Oph C and E regions are pressure-confined. We determine that N2H+ is a good tracer of the bound material of prestellar cores, although we find some evidence for N2H+ freeze-out at the very highest core densities. We find that non-thermal linewidths decrease substantially between the gas traced by C18O and that traced by N2H+, indicating the dissipation of turbulence at higher densities. We find that the critical Bonnor-Ebert stability criterion is not a good indicator of the boundedness of our cores. We detect the pre-brown dwarf candidate Oph B-11 and find a flux density and mass consistent with previous work. We discuss regional variations in the nature of the cores and find further support for our previous hypothesis of a global evolutionary gradient across the cloud from south-west to north-east, indicating sequential star formation across the region.

161. The JCMT Gould Belt Survey: constraints on prestellar core properties in Orion A North

Author

Salji, C. J., Richer, J. S., Buckle, J. V., Hatchell, J., Kirk, H., Beaulieu, S. F., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Jenness, T., Johnstone, D., Mottram, J. C., Nutter, D., Pattle, K., Pineda, J. E., Quinn, C., Tisi, S., Walker-Smith, S., Francesco, J. D., Hogerheijde, M. R., Ward-Thompson, D., Bastien, P., Butner, H., Chen, M., Chrysostomou, A., Coude, S., Davis, C. J., Drabek-Maunder, E., Duarte-Cabral, A., Fiege, J., Friberg, P., Friesen, R., Fuller, G. A., Graves, S., Greaves, J., Gregson, J., Holland, W., Joncas, G., Kirk, J. M., Knee, L. B. G., Mairs, S., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Rawlings, J., Robertson, D., Rosolowsky, E., Rumble, D., Sadavoy, S., Thomas, H., Tothill, N., Viti, S., White, G. J., Wilson, C. D., Wouterloot, J., Yates, J., Zhu, M., Salji, C. J., Richer, J. S., Buckle, J. V., Hatchell, J., Kirk, H., Beaulieu, S. F., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Jenness, T., Johnstone, D., Mottram, J. C., Nutter, D., Pattle, K., Pineda, J. E., Quinn, C., Tisi, S., Walker-Smith, S., Francesco, J. D., Hogerheijde, M. R., Ward-Thompson, D., Bastien, P., Butner, H., Chen, M., Chrysostomou, A., Coude, S., Davis, C. J., Drabek-Maunder, E., Duarte-Cabral, A., Fiege, J., Friberg, P., Friesen, R., Fuller, G. A., Graves, S., Greaves, J., Gregson, J., Holland, W., Joncas, G., Kirk, J. M., Knee, L. B. G., Mairs, S., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Rawlings, J., Robertson, D., Rosolowsky, E., Rumble, D., Sadavoy, S., Thomas, H., Tothill, N., Viti, S., White, G. J., Wilson, C. D., Wouterloot, J., Yates, J., and Zhu, M.

Abstract

We employ SCUBA-2 (Submillimetre Common-User Bolometer Array 2) observations of the Orion A North molecular cloud to derive column density and temperature maps. We apply a novel, Hessian-based structural identification algorithm for detection of prestellar cores to these data, allowing for automated generation of the prestellar mass function. The resulting mass function is observed to peak at $1.39^{+0.18}_{{-}0.19} M_{\odot}$, indicating a star-forming efficiency lower limit of ∼14 per cent when compared with the Orion nebula Cluster initial mass function (IMF) peak. Additionally, the prestellar mass function is observed to decay with a high-mass powerlaw exponent $\alpha = 2.53^{+0.16}_{{-}0.14}$, indicating approximate functional similarity with the Salpeter IMF ($\alpha = 2.35$). This result, when combined with the results of previous investigations suggests a regional dependence of the star-forming efficiency.

162. 2010 BLASTPol Observations of the magnetic field of the filamentary galactic cloud 'Lupus I'

Author

Matthews, Tristan, Ade, P., Angile, F. E., Benton, S. J., Chapman, N. L., Devlin, M. J., Dober, B., Fissel, L. M., Fukui, Y., Gandilo, N., Gundersen, J. O., Hargrave, P., Galitzki, N. B., Klein, J., Korotkov, A., Moncelsi, L., Mroczkowski, T., Netterfield, C., Novak, G., Nutter, D., Olmi, L., Poidevin, F., Savini, G., Scott, D., Shariff, J., Soler, J. D., Thomas, N. E., Truch, M., Tucker, C. E., Tucker, G. S., Ward-Thompson, D., Matthews, Tristan, Ade, P., Angile, F. E., Benton, S. J., Chapman, N. L., Devlin, M. J., Dober, B., Fissel, L. M., Fukui, Y., Gandilo, N., Gundersen, J. O., Hargrave, P., Galitzki, N. B., Klein, J., Korotkov, A., Moncelsi, L., Mroczkowski, T., Netterfield, C., Novak, G., Nutter, D., Olmi, L., Poidevin, F., Savini, G., Scott, D., Shariff, J., Soler, J. D., Thomas, N. E., Truch, M., Tucker, C. E., Tucker, G. S., and Ward-Thompson, D.

Abstract

We present here 350 and 500 micron polarization observations of the Lupus I molecular cloud taken during the 2010 BLASTPol Antarctic flight. Lupus I is a nearby, isolated, young, and filamentary molecular cloud making it an ideal target to test magnetically regulated star formation models. In the presence of intermediate to strong magnetic fields (in comparison to turbulence), these models predict the formation of large filaments extended perpendicular to the local magnetic field direction as gas preferentially collapses along the field lines. We compare the BLASTPol polarization observations with previous optical polarimetry and find a uniform large-scale field direction from low to high density in Lupus I, consistent with magnetically regulated star formation models.

163. Thermal design and performance of the balloon-borne large aperture submillimeter telescope for polarimetry BLASTPol

Author

Soler, J. D., Ade, P. A. R., Angile, F. E., Benton, S. J., Devlin, M. J., Dober, B., Fisel, L. M., Fukui, Y., Galitzki, N., Gandilo, N. N., Klein, J., Korotkov, A. L., Matthews, T. G., Moncelsi, L., Mroczkowski, A., Netterfield, C. B., Novak, G., Nutter, D., Pascale, E., Poidevin, F., Savini, G., Scott, D., Shariff, Jamil A., Thomas, N. E., Truch, M. D., Tucker, C. E., Tucker, G. S., Ward-Thompson, D., Soler, J. D., Ade, P. A. R., Angile, F. E., Benton, S. J., Devlin, M. J., Dober, B., Fisel, L. M., Fukui, Y., Galitzki, N., Gandilo, N. N., Klein, J., Korotkov, A. L., Matthews, T. G., Moncelsi, L., Mroczkowski, A., Netterfield, C. B., Novak, G., Nutter, D., Pascale, E., Poidevin, F., Savini, G., Scott, D., Shariff, Jamil A., Thomas, N. E., Truch, M. D., Tucker, C. E., Tucker, G. S., and Ward-Thompson, D.

Abstract

We present the thermal model of the Balloon-borne Large-Aperture Submillimeter Telescope for Polarimetry (BLASTPol). This instrument was successfully own in two circumpolar flights from McMurdo, Antarctica in 2010 and 2012. During these two flights, BLASTPol obtained unprecedented information about the magnetic field in molecular clouds through the measurement of the polarized thermal emission of interstellar dust grains. The thermal design of the experiment addresses the stability and control of the payload necessary for this kind of measurement. We describe the thermal modeling of the payload including the sun-shielding strategy. We present the in-flight thermal performance of the instrument and compare the predictions of the model with the temperatures registered during the flight. We describe the difficulties of modeling the thermal behavior of the balloon-borne platform and establish landmarks that can be used in the design of future balloon-borne instruments.

164. Attitude determination for balloon-borne experiments

Author

Stepp, Larry M., Gilmozzi, Roberto, Hall, Helen J., Gandilo, N. N., Ade, P. A. R., Amiri, M., Angilè, F. E., Benton, S. J., Bock, J. J., Bond, J. R., Bryan, S. A., Chiang, H. C., Contaldi, C. R., Crill, B. P., Devlin, M. J., Dober, B., Doré, O. P., Farhang, M., Filippini, J. P., Fissel, L. M., Fraisse, A. A., Fukui, Y., Galitzki, N., Gambrel, A. E., Golwala, S., Gudmundsson, J. E., Halpern, M., Hasselfield, M., Hilton, G. C., Holmes, W. A., Hristov, V. V., Irwin, K. D., Jones, W. C., Kermish, Z. D., Klein, J., Korotkov, A. L., Kuo, C. L., MacTavish, C. J., Mason, P. V., Matthews, T. G., Megerian, K. G., Moncelsi, L., Morford, T. A., Mroczkowski, T. K., Nagy, J. M., Netterfield, C. B., Novak, G., Nutter, D., O'Brient, R., Pascale, E., Poidevin, F., Rahlin, A. S., Reintsema, C. D., Ruhl, J. E., Runyan, M. C., Savini, G., Scott, D., Shariff, J. A., Soler, J. D., Thomas, N. E., Trangsrud, A., Truch, M. D., Tucker, C. E., Tucker, G. S., Tucker, R. S., Turner, A. D., Ward-Thompson, D., Weber, A. C., Wiebe, D. V., Young, E. Y., Stepp, Larry M., Gilmozzi, Roberto, Hall, Helen J., Gandilo, N. N., Ade, P. A. R., Amiri, M., Angilè, F. E., Benton, S. J., Bock, J. J., Bond, J. R., Bryan, S. A., Chiang, H. C., Contaldi, C. R., Crill, B. P., Devlin, M. J., Dober, B., Doré, O. P., Farhang, M., Filippini, J. P., Fissel, L. M., Fraisse, A. A., Fukui, Y., Galitzki, N., Gambrel, A. E., Golwala, S., Gudmundsson, J. E., Halpern, M., Hasselfield, M., Hilton, G. C., Holmes, W. A., Hristov, V. V., Irwin, K. D., Jones, W. C., Kermish, Z. D., Klein, J., Korotkov, A. L., Kuo, C. L., MacTavish, C. J., Mason, P. V., Matthews, T. G., Megerian, K. G., Moncelsi, L., Morford, T. A., Mroczkowski, T. K., Nagy, J. M., Netterfield, C. B., Novak, G., Nutter, D., O'Brient, R., Pascale, E., Poidevin, F., Rahlin, A. S., Reintsema, C. D., Ruhl, J. E., Runyan, M. C., Savini, G., Scott, D., Shariff, J. A., Soler, J. D., Thomas, N. E., Trangsrud, A., Truch, M. D., Tucker, C. E., Tucker, G. S., Tucker, R. S., Turner, A. D., Ward-Thompson, D., Weber, A. C., Wiebe, D. V., and Young, E. Y.

Abstract

An attitude determination system for balloon-borne experiments is presented. The system provides pointing information in azimuth and elevation for instruments flying on stratospheric balloons over Antarctica. In-flight attitude is given by the real-time combination of readings from star cameras, a magnetometer, sun sensors, GPS, gyroscopes, tilt sensors and an elevation encoder. Post-flight attitude reconstruction is determined from star camera solutions, interpolated by the gyroscopes using an extended Kalman Filter. The multi-sensor system was employed by the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol), an experiment that measures polarized thermal emission from interstellar dust clouds. A similar system was designed for the upcoming flight of Spider, a Cosmic Microwave Background polarization experiment. The pointing requirements for these experiments are discussed, as well as the challenges in designing attitude reconstruction systems for high altitude balloon flights. In the 2010 and 2012 BLASTPol flights from McMurdo Station, Antarctica, the system demonstrated an accuracy of < 5’ rms in-flight, and < 5” rms post-flight.

165. 2010 BLASTPol Observations of the magnetic field of the filamentary galactic cloud 'Lupus I'

Author

Matthews, Tristan, Ade, P., Angile, F. E., Benton, S. J., Chapman, N. L., Devlin, M. J., Dober, B., Fissel, L. M., Fukui, Y., Gandilo, N., Gundersen, J. O., Hargrave, P., Galitzki, N. B., Klein, J., Korotkov, A., Moncelsi, L., Mroczkowski, T., Netterfield, C., Novak, G., Nutter, D., Olmi, L., Poidevin, F., Savini, G., Scott, D., Shariff, J., Soler, J. D., Thomas, N. E., Truch, M., Tucker, C. E., Tucker, G. S., Ward-Thompson, D., Matthews, Tristan, Ade, P., Angile, F. E., Benton, S. J., Chapman, N. L., Devlin, M. J., Dober, B., Fissel, L. M., Fukui, Y., Gandilo, N., Gundersen, J. O., Hargrave, P., Galitzki, N. B., Klein, J., Korotkov, A., Moncelsi, L., Mroczkowski, T., Netterfield, C., Novak, G., Nutter, D., Olmi, L., Poidevin, F., Savini, G., Scott, D., Shariff, J., Soler, J. D., Thomas, N. E., Truch, M., Tucker, C. E., Tucker, G. S., and Ward-Thompson, D.

Abstract

We present here 350 and 500 micron polarization observations of the Lupus I molecular cloud taken during the 2010 BLASTPol Antarctic flight. Lupus I is a nearby, isolated, young, and filamentary molecular cloud making it an ideal target to test magnetically regulated star formation models. In the presence of intermediate to strong magnetic fields (in comparison to turbulence), these models predict the formation of large filaments extended perpendicular to the local magnetic field direction as gas preferentially collapses along the field lines. We compare the BLASTPol polarization observations with previous optical polarimetry and find a uniform large-scale field direction from low to high density in Lupus I, consistent with magnetically regulated star formation models.

166. BLASTbus electronics: general-purpose readout and control for balloon-borne experiments

Author

Benton, S. J., Ade, P. A., Amiri, M., Angile, F. E., Bock, J. J., Bond, J. R., Sryan, S. A., Chiang, H. C., Contaldi, C. R., Crill, B. P., Devlin, M. J., Dober, B., Dore, O. P., Farhang, M., Filippini, J. P., Fissel, L. M., Fraisse, A. A., Fukui, Y., Galitzki, N., Gambrel, A. E., Gandilo, N. N., Golwala, S. R., Gudmundsson, J. E., Halpern, M., Hasselfield, M., Hilton, G. C., Holmes, W. A., Hristov, V. V., Irwin, K. D., Jones, W. C., Kermish, Z. D., Klein, J., Korotkov, A. L., Kuo, C. L., MacTavish, C. J., Mason, P. V., Matthews, T. G., Megerian, K. G., Moncelsi, L., Morford, T. A., Mroczkowski, T. K., Nagy, J. M., Netterfield, C. B., Novak, G., Nutter, D., O'Brient, R., Ogburn IV, R. W., Pascale, E., Poidevin, F., Rahlin, A. S., Reintsema, C. D., Ruhl, J. E., Runyan, M. C., Savini, G., Scott, D., Shariff, J. A., Soler, J. D., Thomas, N. E., Trangsrud, A., Truch, M. D., Tucker, C. E., Tucker, G. S., Tucker, R. S., Turner, A. D., Ward-Thompson, D., Weber, A. C., Wiebe, D. V., Youn, E. Y., Benton, S. J., Ade, P. A., Amiri, M., Angile, F. E., Bock, J. J., Bond, J. R., Sryan, S. A., Chiang, H. C., Contaldi, C. R., Crill, B. P., Devlin, M. J., Dober, B., Dore, O. P., Farhang, M., Filippini, J. P., Fissel, L. M., Fraisse, A. A., Fukui, Y., Galitzki, N., Gambrel, A. E., Gandilo, N. N., Golwala, S. R., Gudmundsson, J. E., Halpern, M., Hasselfield, M., Hilton, G. C., Holmes, W. A., Hristov, V. V., Irwin, K. D., Jones, W. C., Kermish, Z. D., Klein, J., Korotkov, A. L., Kuo, C. L., MacTavish, C. J., Mason, P. V., Matthews, T. G., Megerian, K. G., Moncelsi, L., Morford, T. A., Mroczkowski, T. K., Nagy, J. M., Netterfield, C. B., Novak, G., Nutter, D., O'Brient, R., Ogburn IV, R. W., Pascale, E., Poidevin, F., Rahlin, A. S., Reintsema, C. D., Ruhl, J. E., Runyan, M. C., Savini, G., Scott, D., Shariff, J. A., Soler, J. D., Thomas, N. E., Trangsrud, A., Truch, M. D., Tucker, C. E., Tucker, G. S., Tucker, R. S., Turner, A. D., Ward-Thompson, D., Weber, A. C., Wiebe, D. V., and Youn, E. Y.

Abstract

We present the second generation BLASTbus electronics. The primary purposes of this system are detector readout, attitude control, and cryogenic housekeeping, for balloon-borne telescopes. Readout of neutron transmutation doped germanium (NTD-Ge) bolometers requires low noise and parallel acquisition of hundreds of analog signals. Controlling a telescope's attitude requires the capability to interface to a wide variety of sensors and motors, and to use them together in a fast, closed loop. To achieve these different goals, the BLASTbus system employs a flexible motherboard-daughterboard architecture. The programmable motherboard features a digital signal processor (DSP) and field-programmable gate array (FPGA), as well as slots for three daughterboards. The daughterboards provide the interface to the outside world, with versions for analog to digital conversion, and optoisolated digital input/output. With the versatility afforded by this design, the BLASTbus also finds uses in cryogenic, thermometry, and power systems. For accurate timing control to tie everything together, the system operates in a fully synchronous manner. BLASTbus electronics have been successfully deployed to the South Pole, and own on stratospheric balloons.

167. The JCMT Gould Belt Survey: first results from SCUBA-2 observations of the Cepheus Flare region

Author

Pattle, K., Ward-Thompson, D., Kirk, J. M., Di Francesco, J., Kirk, H., Mottram, J. C., Keown, J., Buckle, J., Beaulieu, S. F., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Hatchell, J., Jenness, T., Johnstone, D., Nutter, D., Pineda, J. E., Quinn, C., Salji, C., Tisi, S., Walker-Smith, S., Hogerheijde, M. R., Bastien, P., Bresnahan, D., Butner, H., Chen, M., Chrysostomou, A., Coudé, S., Davis, C. J., Drabek-Maunder, E., Duarte-Cabral, A., Fiege, J., Friberg, P., Friesen, R., Fuller, G. A., Graves, S., Greaves, J., Gregson, J., Holland, W., Joncas, G., Knee, L. B. G., Mairs, S., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Mowat, C., Rawlings, J., Richer, J., Robertson, D., Rosolowsky, E., Rumble, D., Sadavoy, S., Thomas, H., Tothill, N., Viti, S., White, G. J., Wouterloot, J., Yates, J., Zhu, M., Pattle, K., Ward-Thompson, D., Kirk, J. M., Di Francesco, J., Kirk, H., Mottram, J. C., Keown, J., Buckle, J., Beaulieu, S. F., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Hatchell, J., Jenness, T., Johnstone, D., Nutter, D., Pineda, J. E., Quinn, C., Salji, C., Tisi, S., Walker-Smith, S., Hogerheijde, M. R., Bastien, P., Bresnahan, D., Butner, H., Chen, M., Chrysostomou, A., Coudé, S., Davis, C. J., Drabek-Maunder, E., Duarte-Cabral, A., Fiege, J., Friberg, P., Friesen, R., Fuller, G. A., Graves, S., Greaves, J., Gregson, J., Holland, W., Joncas, G., Knee, L. B. G., Mairs, S., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Mowat, C., Rawlings, J., Richer, J., Robertson, D., Rosolowsky, E., Rumble, D., Sadavoy, S., Thomas, H., Tothill, N., Viti, S., White, G. J., Wouterloot, J., Yates, J., and Zhu, M.

Abstract

We present observations of the Cepheus Flare obtained as part of the James Clerk Maxwell Telescope (JCMT) Gould Belt Legacy Survey (GBLS) with the SCUBA-2 instrument. We produce a catalogue of sources found by SCUBA-2, and separate these into starless cores and protostars. We determine masses and densities for each of our sources, using source temperatures determined by the Herschel Gould Belt Survey. We compare the properties of starless cores in four different molecular clouds: L1147/58, L1172/74, L1251 and L1228. We find that the core mass functions for each region typically show shallower-than Salpeter behaviour. We find that L1147/58 and L1228 have a high ratio of starless cores to Class II protostars, while L1251 and L1174 have a low ratio, consistent with the latter regions being more active sites of current star formation, while the former are forming stars less actively.We determine that if modelled as thermally supported Bonnor–Ebert spheres, most of our cores have stable configurations accessible to them.We estimate the external pressures on our cores using archival 13CO velocity dispersion measurements and find that our cores are typically pressure confined, rather than gravitationally bound.We perform a virial analysis on our cores, and find that they typically cannot be supported against collapse by internal thermal energy alone, due primarily to the measured external pressures. This suggests that the dominant mode of internal support in starless cores in the Cepheus Flare is either non-thermal motions or internal magnetic fields.

168. The JCMT Gould Belt Survey: constraints on prestellar core properties in Orion A North

Author

Salji, C. J., Richer, J. S., Buckle, J. V., Hatchell, J., Kirk, H., Beaulieu, S. F., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Jenness, T., Johnstone, D., Mottram, J. C., Nutter, D., Pattle, K., Pineda, J. E., Quinn, C., Tisi, S., Walker-Smith, S., Francesco, J. D., Hogerheijde, M. R., Ward-Thompson, D., Bastien, P., Butner, H., Chen, M., Chrysostomou, A., Coude, S., Davis, C. J., Drabek-Maunder, E., Duarte-Cabral, A., Fiege, J., Friberg, P., Friesen, R., Fuller, G. A., Graves, S., Greaves, J., Gregson, J., Holland, W., Joncas, G., Kirk, J. M., Knee, L. B. G., Mairs, S., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Rawlings, J., Robertson, D., Rosolowsky, E., Rumble, D., Sadavoy, S., Thomas, H., Tothill, N., Viti, S., White, G. J., Wilson, C. D., Wouterloot, J., Yates, J., Zhu, M., Salji, C. J., Richer, J. S., Buckle, J. V., Hatchell, J., Kirk, H., Beaulieu, S. F., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Jenness, T., Johnstone, D., Mottram, J. C., Nutter, D., Pattle, K., Pineda, J. E., Quinn, C., Tisi, S., Walker-Smith, S., Francesco, J. D., Hogerheijde, M. R., Ward-Thompson, D., Bastien, P., Butner, H., Chen, M., Chrysostomou, A., Coude, S., Davis, C. J., Drabek-Maunder, E., Duarte-Cabral, A., Fiege, J., Friberg, P., Friesen, R., Fuller, G. A., Graves, S., Greaves, J., Gregson, J., Holland, W., Joncas, G., Kirk, J. M., Knee, L. B. G., Mairs, S., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Rawlings, J., Robertson, D., Rosolowsky, E., Rumble, D., Sadavoy, S., Thomas, H., Tothill, N., Viti, S., White, G. J., Wilson, C. D., Wouterloot, J., Yates, J., and Zhu, M.

Abstract

We employ SCUBA-2 (Submillimetre Common-User Bolometer Array 2) observations of the Orion A North molecular cloud to derive column density and temperature maps. We apply a novel, Hessian-based structural identification algorithm for detection of prestellar cores to these data, allowing for automated generation of the prestellar mass function. The resulting mass function is observed to peak at $1.39^{+0.18}_{{-}0.19} M_{\odot}$, indicating a star-forming efficiency lower limit of ∼14 per cent when compared with the Orion nebula Cluster initial mass function (IMF) peak. Additionally, the prestellar mass function is observed to decay with a high-mass powerlaw exponent $\alpha = 2.53^{+0.16}_{{-}0.14}$, indicating approximate functional similarity with the Salpeter IMF ($\alpha = 2.35$). This result, when combined with the results of previous investigations suggests a regional dependence of the star-forming efficiency.

169. 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

Author

Pattle, K., Ward-Thompson, D., Kirk, J. M., White, G. J., Drabek-Maunder, E., Buckle, J., Beaulieu, S. F., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Hatchell, J., Kirk, H., Jenness, T., Johnstone, D., Mottram, J. C., Nutter, D., Pineda, J. E., Quinn, C., Salji, C., Tisi, S., Walker-Smith, S., Di Francesco, J., Hogerheijde, M. R., André, Ph., Bastien, P., Bresnahan, D., Butner, H., Chen, M., Chrysostomou, A., Coude, S., Davis, C. J., Duarte-Cabral, A., Fiege, J., Friberg, P., Friesen, R., Fuller, G. A., Graves, S., Greaves, J., Gregson, J., Griffin, M. J., Holland, W., Joncas, G., Knee, L. B. G., Könyves, V., Mairs, S., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Rawlings, J., Richer, J., Robertson, D., Rosolowsky, E., Rumble, D., Sadavoy, S., Spinoglio, L., Thomas, H., Tothill, N., Viti, S., Wouterloot, J., Yates, J., Zhu, M., Pattle, K., Ward-Thompson, D., Kirk, J. M., White, G. J., Drabek-Maunder, E., Buckle, J., Beaulieu, S. F., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Hatchell, J., Kirk, H., Jenness, T., Johnstone, D., Mottram, J. C., Nutter, D., Pineda, J. E., Quinn, C., Salji, C., Tisi, S., Walker-Smith, S., Di Francesco, J., Hogerheijde, M. R., André, Ph., Bastien, P., Bresnahan, D., Butner, H., Chen, M., Chrysostomou, A., Coude, S., Davis, C. J., Duarte-Cabral, A., Fiege, J., Friberg, P., Friesen, R., Fuller, G. A., Graves, S., Greaves, J., Gregson, J., Griffin, M. J., Holland, W., Joncas, G., Knee, L. B. G., Könyves, V., Mairs, S., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Rawlings, J., Richer, J., Robertson, D., Rosolowsky, E., Rumble, D., Sadavoy, S., Spinoglio, L., Thomas, H., Tothill, N., Viti, S., Wouterloot, J., Yates, J., and Zhu, M.

Abstract

In this paper, we present the first observations of the Ophiuchus molecular cloud performed as part of the James Clerk Maxwell Telescope (JCMT) Gould Belt Survey (GBS) with the SCUBA-2 instrument. We demonstrate methods for combining these data with previous HARP CO, Herschel, and IRAM N2H+ observations in order to accurately quantify the properties of the SCUBA-2 sources in Ophiuchus. We produce a catalogue of all of the sources found by SCUBA-2. We separate these into protostars and starless cores. We list all of the starless cores and perform a full virial analysis, including external pressure. This is the first time that external pressure has been included in this level of detail. We find that the majority of our cores are either bound or virialized. Gravitational energy and external pressure are on average of a similar order of magnitude, but with some variation from region to region. We find that cores in the Oph A region are gravitationally bound prestellar cores, while cores in the Oph C and E regions are pressure-confined. We determine that N2H+ is a good tracer of the bound material of prestellar cores, although we find some evidence for N2H+ freeze-out at the very highest core densities. We find that non-thermal linewidths decrease substantially between the gas traced by C18O and that traced by N2H+, indicating the dissipation of turbulence at higher densities. We find that the critical Bonnor-Ebert stability criterion is not a good indicator of the boundedness of our cores. We detect the pre-brown dwarf candidate Oph B-11 and find a flux density and mass consistent with previous work. We discuss regional variations in the nature of the cores and find further support for our previous hypothesis of a global evolutionary gradient across the cloud from south-west to north-east, indicating sequential star formation across the region.

170. 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

Author

Pattle, K., Ward-Thompson, D., Kirk, J. M., White, G. J., Drabek-Maunder, E., Buckle, J., Beaulieu, S. F., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Hatchell, J., Kirk, H., Jenness, T., Johnstone, D., Mottram, J. C., Nutter, D., Pineda, J. E., Quinn, C., Salji, C., Tisi, S., Walker-Smith, S., Francesco, J. Di, Hogerheijde, M. R., André, Ph, Bastien, P., Bresnahan, D., Butner, H., Chen, M., Chrysostomou, A., Coude, S., Davis, C. J., Duarte-Cabral, A., Fiege, J., Friberg, P., Friesen, R., Fuller, G. A., Graves, S., Greaves, J., Gregson, J., Griffin, M. J., Holland, W., Joncas, G., Knee, L. B. G., Könyves, V., Mairs, S., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Rawlings, J., Richer, J., Robertson, D., Rosolowsky, E., Rumble, D., Sadavoy, S., Spinoglio, L., Thomas, H., Tothill, N., Viti, S., Wouterloot, J., Yates, J., Zhu, M., Pattle, K., Ward-Thompson, D., Kirk, J. M., White, G. J., Drabek-Maunder, E., Buckle, J., Beaulieu, S. F., Berry, D. S., Broekhoven-Fiene, H., Currie, M. J., Fich, M., Hatchell, J., Kirk, H., Jenness, T., Johnstone, D., Mottram, J. C., Nutter, D., Pineda, J. E., Quinn, C., Salji, C., Tisi, S., Walker-Smith, S., Francesco, J. Di, Hogerheijde, M. R., André, Ph, Bastien, P., Bresnahan, D., Butner, H., Chen, M., Chrysostomou, A., Coude, S., Davis, C. J., Duarte-Cabral, A., Fiege, J., Friberg, P., Friesen, R., Fuller, G. A., Graves, S., Greaves, J., Gregson, J., Griffin, M. J., Holland, W., Joncas, G., Knee, L. B. G., Könyves, V., Mairs, S., Marsh, K., Matthews, B. C., Moriarty-Schieven, G., Rawlings, J., Richer, J., Robertson, D., Rosolowsky, E., Rumble, D., Sadavoy, S., Spinoglio, L., Thomas, H., Tothill, N., Viti, S., Wouterloot, J., Yates, J., and Zhu, M.

Abstract

In this paper, we present the first observations of the Ophiuchus molecular cloud performed as part of the James Clerk Maxwell Telescope (JCMT) Gould Belt Survey (GBS) with the SCUBA-2 instrument. We demonstrate methods for combining these data with previous HARP CO, Herschel, and IRAM N2H+ observations in order to accurately quantify the properties of the SCUBA-2 sources in Ophiuchus. We produce a catalogue of all of the sources found by SCUBA-2. We separate these into protostars and starless cores. We list all of the starless cores and perform a full virial analysis, including external pressure. This is the first time that external pressure has been included in this level of detail. We find that the majority of our cores are either bound or virialized. Gravitational energy and external pressure are on average of a similar order of magnitude, but with some variation from region to region. We find that cores in the Oph A region are gravitationally bound prestellar cores, while cores in the Oph C and E regions are pressure-confined. We determine that N2H+ is a good tracer of the bound material of prestellar cores, although we find some evidence for N2H+ freeze-out at the very highest core densities. We find that non-thermal linewidths decrease substantially between the gas traced by C18O and that traced by N2H+, indicating the dissipation of turbulence at higher densities. We find that the critical Bonnor-Ebert stability criterion is not a good indicator of the boundedness of our cores. We detect the pre-brown dwarf candidate Oph B-11 and find a flux density and mass consistent with previous work. We discuss regional variations in the nature of the cores and find further support for our previous hypothesis of a global evolutionary gradient across the cloud from south-west to north-east, indicating sequential star formation across the region

197. Curriculum restructure to answer critical needs in packaging for energy efficiency/renewable energy systems, wireless, and mixed-signal systems areas

Author

Brown, W., primary, Elshabini, A., additional, Ang, S., additional, Balda, J., additional, Barlow, F., additional, Coubillion, R., additional, Malshe, A., additional, Malstrom, R., additional, Mantooth, A., additional, Martin, T., additional, Naseem, H., additional, Jones, R., additional, Waite, W., additional, Brown, R., additional, Schmitt, N., additional, Nutter, D., additional, Salamo, G., additional, Schaper, L., additional, Schmidt, W., additional, Selvam, R., additional, Singh, S., additional, Olejniczak, K., additional, Ulrich, R., additional, Yeargan, J., additional, Yaz, E., additional, and White, W., additional

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