Beam Size, Shape and Efficiencies for the ATNF Mopra Radio Telescope at 86–115 GHz

Ladd, Ned; Purcell, Cormac; Wong, Tony; Robertson, Stuart

doi:10.1071/as04068

Cited by 177 publications

(218 citation statements)

References 6 publications

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“…The Monolithic Microwave Integrated Circuit (MMIC) receiver covers the spectral range from 77 to 117 GHz and the 8-GHz bandpass of the MOPS was centred at 112.5 GHz to include these four isotopologues. The angular resolution of the Mopra beam size is 33 arcsec FWHM (Ladd et al 2005), and after the median filter convolution applied in the data reduction is around 35 arcsec in the final data set. The extended beam efficiency, η XB = 0.55 at 115 GHz, was also determined by Ladd et al This is used to convert brightness temperatures into line fluxes for determination of source parameters (rather than the main beam efficiency factor, of η MB = 0.42).…”

Section: Observationsmentioning

confidence: 99%

The Mopra Southern Galactic Plane CO Survey

Burton

Braiding

Glueck

et al. 2013

Publ. Astron. Soc. Aust.

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We present the first results from a new carbon monoxide (CO) survey of the southern Galactic plane being conducted with the Mopra radio telescope in Australia. The 12 CO, 13 CO, and C 18 O J = 1-0 lines are being mapped over the l = 305 • -345 • , b = ±0.5 • portion of the fourth quadrant of the Galaxy, at 35 arcsec spatial and 0.1 km s −1 spectral resolution. The survey is being undertaken with two principal science objectives: (i) to determine where and how molecular clouds are forming in the Galaxy and (ii) to probe the connection between molecular clouds and the 'missing' gas inferred from gamma-ray observations. We describe the motivation for the survey, the instrumentation and observing techniques being applied, and the data reduction and analysis methodology. In this paper, we present the data from the first degree surveyed, l = 323 • -324 • , b = ±0.5 • . We compare the data to the previous CO survey of this region and present metrics quantifying the performance being achieved; the rms sensitivity per 0.1 km s −1 velocity channel is ß1.5 K for 12 CO and ß0.7 K for the other lines. We also present some results from the region surveyed, including line fluxes, column densities, molecular masses, 12 CO/ 13 CO line ratios, and 12 CO optical depths. We also examine how these quantities vary as a function of distance from the Sun when averaged over the 1 square degree survey area. Approximately 2 × 10 6 M of molecular gas is found along the G323 sightline, with an average H 2 number density of n H 2 ∼ 1 cm −3 within the Solar circle. The CO data cubes will be made publicly available as they are published.

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Section: Observationsmentioning

confidence: 99%

The Mopra Southern Galactic Plane CO Survey

Burton

Braiding

Glueck

et al. 2013

Publ. Astron. Soc. Aust.

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“…The references are: (a) Mookerjea et al (2004); (b) Becklin et al (1973); (c) Murphy et al (2010); (d) Figuerêdo et al (2005); (e) Breen et al (2007); (f) Caswell (1998); (g) Caswell et al (1995). Ladd et al (2005) and the beam efficiencies used are as listed there. The observing bandwidth was configured so that the central channel corresponded to −50 km s −1 , the approximate velocity at which the emission from the GMC complex is centred.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

“…where T * A is the measured intensity and ην the beam efficiency (taken as 0.55 from Ladd et al (2005)). f is the beam filling factor for the emission, Jν (T ) = [hν/k]/[e (hν/kT ) − 1] with Tex being the excitation temperature and TBG being the temperature of the cosmic background radiation (i.e.…”

Section: Molecular Lines: Optical Depthsmentioning

confidence: 99%

Infall, outflow, and turbulence in massive star-forming cores in the G333 giant molecular cloud

Wiles

Redman

et al. 2015

Mon. Not. R. Astron. Soc.

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We present molecular line imaging observations of three massive molecular outflow sources, G333.6-0.2, G333.1-0.4, and G332.8-0.5, all of which also show evidence for infall, within the G333 giant molecular cloud (GMC). All three are within a beam size (36 arcseconds) of IRAS sources, 1.2-mm dust clumps, various masing species and radio continuum-detected Hii regions and hence are associated with high-mass star formation. We present the molecular line data and derive the physical properties of the outflows including the mass, kinematics, and energetics and discuss the inferred characteristics of their driving sources. Outflow masses are of 10 to 40 M ⊙ in each lobe, with core masses of order 10 3 M ⊙ . outflow size scales are a few tenth of a parsec, timescales are of several ×10 4 years, mass loss rates a few ×10 −4 M ⊙ /yr. We also find the cores are turbulent and highly supersonic.

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“…Note that all spectra and Gaussian profile fitting are shown and performed on the T * A scale. To convert to main-beam brightness temperature (T mb ), the antenna temperature (T * A ) should be divided by the main-beam efficiency (η mb ) of 0.49 (Ladd et al 2005).…”

Section: Spectra Towards Each High-mass Clumpmentioning

confidence: 99%

Molecular Line Emission Towards High-Mass Clumps: The MALT90 Catalogue

Rathborne

Whitaker

Jackson

et al. 2016

Publ. Astron. Soc. Aust.

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The Millimetre Astronomy Legacy Team 90 GHz survey aims to characterise the physical and chemical evolution of high-mass clumps. Recently completed, it mapped 90 GHz line emission towards 3 246 high-mass clumps identified from the ATLASGAL 870 μm Galactic plane survey. By utilising the broad frequency coverage of the Mopra telescope's spectrometer, maps in 16 different emission lines were simultaneously obtained. Here, we describe the first catalogue of the detected line emission, generated by Gaussian profile fitting to spectra extracted towards each clumps' 870 μm dust continuum peak. Synthetic spectra show that the catalogue has a completeness of >95%, a probability of a false-positive detection of <0.3%, and a relative uncertainty in the measured quantities of <20% over the range of detection criteria. The detection rates are highest for the (1-0) transitions of HCO + , HNC, N 2 H + , and HCN (∼77-89%). Almost all clumps (∼95%) are detected in at least one of the molecular transitions, just over half of the clumps (∼53%) are detected in four or more of the transitions, while only one clump is detected in 13 transitions. We find several striking trends in the ensemble of properties for the different molecular transitions when plotted as a function of the clumps' evolutionary state as estimated from Spitzer mid-IR images, including (1) HNC is relatively brighter in colder, less evolved clumps than those that show active star formation, (2) N 2 H + is relatively brighter in the earlier stages, (3) that the observed optical depth decreases as the clumps evolve, and (4) the optically thickest HCO + emission shows a 'blue-red asymmetry' indicating overall collapse that monotonically decreases as the clumps evolve. This catalogue represents the largest compiled database of line emission towards high-mass clumps and is a valuable data set for detailed studies of these objects.

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Beam Size, Shape and Efficiencies for the ATNF Mopra Radio Telescope at 86–115 GHz

Cited by 177 publications

References 6 publications

The Mopra Southern Galactic Plane CO Survey

The Mopra Southern Galactic Plane CO Survey

Infall, outflow, and turbulence in massive star-forming cores in the G333 giant molecular cloud

Molecular Line Emission Towards High-Mass Clumps: The MALT90 Catalogue

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