Automated reduction of sub-millimetre single-dish heterodyne data from the James Clerk Maxwell Telescope using orac-dr

Jenness, Tim; Currie, Malcolm J.; Tilanus, R. P. J.; Cavanagh, B.; Berry, D. S.; Leech, J.; Rizzi, L.

doi:10.1093/mnras/stv1545

Cited by 39 publications

(32 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For The initial reduction of the JCMT jiggle maps was performed using the most up-to-date version of the starlink 5 reduction package orac-dr (Jenness et al 2015). Similar initial reduction was performed for the APEX data using gildas-class 6 .…”

Section: Resultsmentioning

confidence: 99%

Outflows, infall and evolution of a sample of embedded low-mass protostars

Mottram

Dishoeck

Kristensen

et al. 2017

A&A

123

View full text Add to dashboard Cite

Context. Herschel observations of water and highly excited CO (J >9) have allowed the physical and chemical conditions in the more active parts of protostellar outflows to be quantified in detail for the first time. However, to date, the studied samples of Class 0/I protostars in nearby star-forming regions have been selected from bright, well-known sources and have not been large enough for statistically significant trends to be firmly established. Aims. We aim to explore the relationships between the outflow, envelope and physical properties of a flux-limited sample of embedded low-mass Class 0/I protostars. Methods. We present spectroscopic observations in H 2 O, CO and related species with Herschel HIFI and PACS, as well as ground-based follow-up with the JCMT and APEX in CO, HCO + and isotopologues, of a sample of 49 nearby (d <500 pc) candidate protostars selected from Spitzer and Herschel photometric surveys of the Gould Belt. This more than doubles the sample of sources observed by the WISH and DIGIT surveys. These data are used to study the outflow and envelope properties of these sources. We also compile their continuum spectral energy distributions (SEDs) from the near-IR to mm wavelengths in order to constrain their physical properties (e.g. L bol , T bol and M env ). Results. Water emission is dominated by shocks associated with the outflow, rather than the cooler, slower entrained outflowing gas probed by ground-based CO observations. These shocks become less energetic as sources evolve from Class 0 to Class I. Outflow force, measured from low-J CO, also decreases with source evolutionary stage, while the fraction of mass in the outflow relative to the total envelope (i.e. M out /M env ) remains broadly constant between Class 0 and I. The median value of ∼1% is consistent with a core to star formation efficiency on the order of 50% and an outflow duty cycle on the order of 5%. Entrainment efficiency, as probed by F CO /Ṁ acc , is also invariant with source properties and evolutionary stage. The median value implies a velocity at the wind launching radius of 6.3 km s −1 , which in turn suggests an entrainment efficiency of between 30 and 60% if the wind is launched at ∼1AU, or close to 100% if launched further out. L[O i] is strongly correlated with L bol but not with M env , in contrast to low-J CO, which is more closely correlated with the latter than the former. This suggests that [O i] traces the present-day accretion activity of the source while CO traces time-averaged accretion over the dynamical timescale of the outflow. H 2 O is more strongly correlated with M env than L bol , but the difference is smaller than low-J CO, consistent with water emission primarily tracing actively shocked material between the wind, traced by [O i], and the entrained molecular outflow, traced by low-J CO. L[O i] does not vary from Class 0 to Class I, unlike CO and H 2 O. This is likely due to the ratio of atomic to molecular gas in the wind increasing as the source evolves, balancing out the decrease in ...

show abstract

Section: Resultsmentioning

confidence: 99%

Outflows, infall and evolution of a sample of embedded low-mass protostars

Mottram

Dishoeck

Kristensen

et al. 2017

A&A

123

View full text Add to dashboard Cite

show abstract

“…We reduce the data using the Starlink 41 software package ORAC-DR (Currie et al 2014;Jenness et al 2015) to obtain pipeline-processed data and then convert the spectra to GILDAS/CLASS 42 format for further data processing. A recipe of REDUCE_SCIENCE_BROADLINE with default parameters was adopted for the ORAC-DR pipeline.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

The MALATANG Survey: The L_GAS–L_IR Correlation on Sub-kiloparsec Scale in Six Nearby Star-forming Galaxies as Traced by HCN J = 4 → 3 and HCO⁺ J = 4 → 3

Tan

Gao

Zhang

et al. 2018

ApJ

Self Cite

View full text Add to dashboard Cite

We present J HCN 4 3 =  and J HCO 4 3 =  + maps of six nearby star-forming galaxies, NGC 253, NGC 1068, IC 342, M82, M83, and NGC 6946, obtained with the James Clerk Maxwell Telescope as part of the MALATANG survey. All galaxies were mapped in the central 2′×2′region at 14″ (FWHM) resolution (corresponding to linear scales of ∼0.2-1.0 kpc). The L IR -L′ dense relation, where the dense gas is traced by the J HCN 4 3 =  and the J HCO 4 3 =  + emission, measured in our sample of spatially resolved galaxies is found to follow the linear correlation established globally in galaxies within the scatter. We find that the luminosity ratio, L IR /L′ dense , shows systematic variations with L IR within individual spatially resolved galaxies, whereas the galaxy-integrated ratios vary little. A rising trend is also found between L IR /L′ dense ratio and the warm-dust temperature gauged by the 70 μm/100 μm flux ratio. We find that the luminosity ratios of IR/HCN (4-3) and IR/HCO + (4-3), which can be taken as a proxy for the star formation efficiency (SFE) in the dense molecular gas

show abstract

“…All HARP data were processed with the ORAC-DR heterodyne pipeline (Jenness et al 2015) using the REDUCED_SCIENCE_NAR-ROWLINE recipe. In brief, this sorts the time series into temporal order and identifies and rejects spectra affected by high-frequency noise and low-frequency nonastronomical signal using a nonlinearity coefficient of 0.08 (where the best spectra have coefficients <0.025).…”

Section: Harpmentioning

confidence: 99%

The JCMT Gould Belt Survey: A First Look at the Auriga–California Molecular Cloud with SCUBA-2

Broekhoven-Fiene

Matthews

Harvey

et al. 2018

ApJ

View full text Add to dashboard Cite

We present 850 and 450 μm observations of the dense regions within the Auriga-California molecular cloud using SCUBA-2 as part of the JCMT Gould Belt Legacy Survey to identify candidate protostellar objects, measure the masses of their circumstellar material (disk and envelope), and compare the star formation to that in the Orion A molecular cloud. We identify 59 candidate protostars based on the presence of compact submillimeter emission, complementing these observations with existing Herschel/SPIRE maps. Of our candidate protostars, 24 are associated with young stellar objects (YSOs) in the Spitzer and Herschel/PACS catalogs of 166 and 60 YSOs, respectively (177 unique), confirming their protostellar nature. The remaining 35 candidate protostars are in regions, particularly around LkHα101, where the background cloud emission is too bright to verify or rule out the presence of the compact 70 μm emission that is expected for a protostellar source. We keep these candidate protostars in our sample but note that they may indeed be prestellar in nature. Our observations are sensitive to the high end of the mass distribution in Auriga-Cal. We find that the disparity between the richness of infrared star-forming objects in Orion A and the sparsity in AurigaCal extends to the submillimeter, suggesting that the relative star formation rates have not varied over the Class II lifetime and that Auriga-Cal will maintain a lower star formation efficiency.

show abstract

Automated reduction of sub-millimetre single-dish heterodyne data from the James Clerk Maxwell Telescope using orac-dr

Cited by 39 publications

References 38 publications

Outflows, infall and evolution of a sample of embedded low-mass protostars

Outflows, infall and evolution of a sample of embedded low-mass protostars

The MALATANG Survey: The L_GAS–L_IR Correlation on Sub-kiloparsec Scale in Six Nearby Star-forming Galaxies as Traced by HCN J = 4 → 3 and HCO⁺ J = 4 → 3

The JCMT Gould Belt Survey: A First Look at the Auriga–California Molecular Cloud with SCUBA-2

Contact Info

Product

Resources

About

Automated reduction of sub-millimetre single-dish heterodyne data from the James Clerk Maxwell Telescope using orac-dr

Cited by 39 publications

References 38 publications

Outflows, infall and evolution of a sample of embedded low-mass protostars

Outflows, infall and evolution of a sample of embedded low-mass protostars

The MALATANG Survey: The LGAS–LIR Correlation on Sub-kiloparsec Scale in Six Nearby Star-forming Galaxies as Traced by HCN J = 4 → 3 and HCO+ J = 4 → 3

The JCMT Gould Belt Survey: A First Look at the Auriga–California Molecular Cloud with SCUBA-2

Contact Info

Product

Resources

About

The MALATANG Survey: The L_GAS–L_IR Correlation on Sub-kiloparsec Scale in Six Nearby Star-forming Galaxies as Traced by HCN J = 4 → 3 and HCO⁺ J = 4 → 3