ORCID Profile
0000-0001-7020-6176
Current Organisation
University of New South Wales
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Astronomical and Space Sciences | Astronomy And Astrophysics | Astronomical and Space Instrumentation | Astrobiology | High Energy Astrophysics; Cosmic Rays | Galactic Astronomy | Cosmology and Extragalactic Astronomy |
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Physical Sciences | Physical sciences | Higher education | Scientific instrumentation | Education and Training Systems not elsewhere classified | Education and Training not elsewhere classified
Related Links
Publications
A 3-mm molecular line study of the Central Molecular Zone
Publisher: EDP Sciences
Date: 2008
DOI: 10.1051/EAS:0831015
High-resolution observations of the J = 1-0 transition of cyanoacetylene in Sgr B2
Publisher: Oxford University Press (OUP)
Date: 1999
A Centimeter-wave Study of Methanol and Ammonia Isotopologues in Sgr B2(N): Physical and Chemical Differentiation between Two Hot Cores
Publisher: American Astronomical Society
Date: 18-12-2018
ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions – I. Survey description and a first look at G9.62+0.19
Publisher: Oxford University Press (OUP)
Date: 06-06-2020
Abstract: The ATOMS, standing for ALMA Three-millimeter Observations of Massive Star-forming regions, survey has observed 146 active star-forming regions with ALMA band 3, aiming to systematically investigate the spatial distribution of various dense gas tracers in a large s le of Galactic massive clumps, to study the roles of stellar feedback in star formation, and to characterize filamentary structures inside massive clumps. In this work, the observations, data analysis, and ex le science of the ATOMS survey are presented, using a case study for the G9.62+0.19 complex. Toward this source, some transitions, commonly assumed to trace dense gas, including CS J = 2−1, HCO+J = 1−0, and HCN J = 1−0, are found to show extended gas emission in low-density regions within the clump less than 25 per cent of their emission is from dense cores. SO, CH3OH, H13CN, and HC3N show similar morphologies in their spatial distributions and reveal well the dense cores. Widespread narrow SiO emission is present (over ∼1 pc), which may be caused by slow shocks from large–scale colliding flows or H ii regions. Stellar feedback from an expanding H ii region has greatly reshaped the natal clump, significantly changed the spatial distribution of gas, and may also account for the sequential high-mass star formation in the G9.62+0.19 complex. The ATOMS survey data can be jointly analysed with other survey data, e.g. MALT90, Orion B, EMPIRE, ALMA_IMF, and ALMAGAL, to deepen our understandings of ‘dense gas’ star formation scaling relations and massive protocluster formation.
Recent Science from Australian Large-Scale Millimetre Mapping Projects: Proceedings from a Swinburne University Workshop
Publisher: Cambridge University Press (CUP)
Date: 2009
DOI: 10.1071/AS08027
Abstract: Since the recent upgrades to the Australia Telescope National Facility (ATNF) Mopra telescope back-end and receiver system, it has risen from an under-subscribed facility to a sought-after instrument with heavy international competition to gain time. Furthermore, the introduction of the on-the-fly mapping capability in 2004 has made this technique one of Mopra's most popular observing modes. In addition, the recent upgrade of the NANTEN millimetre-wavelength telescope to the sub-millimetre NANTEN2 instrument, has provided a complementary, higher-frequency facility to Mopra. A two-day workshop was held at Swinburne University in June 2008 to disseminate the current state of ongoing large-scale mapping projects and associated spin-offs that the telescopes' upgrades have facilitated, and to decide upon future research directions. Here, we provide a summary of the result-oriented talks as a record of the state of Australian-access single-dish millimetre science in 2008.
Water masers and ammonia (1, 1) and (2, 2) towards six regions in the Carina Nebula
Publisher: Oxford University Press (OUP)
Date: 14-10-2018
MOPRA CO OBSERVATIONS OF THE BUBBLE H II REGION RCW 120
Publisher: American Astronomical Society
Date: 18-02-2015
Chemical differentiation in Sagittarius B2(N): first high resolution results
Publisher: Cambridge University Press (CUP)
Date: 10-2013
DOI: 10.1017/S174392131400057X
Abstract: Sgr B2 is an active high mass star forming region in the Galactic center and the pre-eminent interstellar source of organic chemistry. Newly available broad bandwidth radio interferometry data enables a spatially resolved study of the chemical environments within the Sgr B2(N) core. We present selections from a 30 - 50 GHz spectral line survey conducted with the ATCA.
PLANCK COLD CLUMPS IN THE λ ORIONIS COMPLEX. I. DISCOVERY OF AN EXTREMELY YOUNG CLASS 0 PROTOSTELLAR OBJECT AND A PROTO-BROWN DWARF CANDIDATE IN THE BRIG
Publisher: American Astronomical Society
Date: 14-01-2016
Low-Frequency Carbon Recombination Lines in the Orion Molecular Cloud Complex
Publisher: Cambridge University Press (CUP)
Date: 2018
DOI: 10.1017/PASA.2018.13
Abstract: We detail tentative detections of low-frequency carbon radio recombination lines from within the Orion molecular cloud complex observed at 99–129 MHz. These tentative detections include one alpha transition and one beta transition over three locations and are located within the diffuse regions of dust observed in the infrared at 100 μm, the Hα emission detected in the optical, and the synchrotron radiation observed in the radio. With these observations, we are able to study the radiation mechanism transition from collisionally pumped to radiatively pumped within the H ii regions within the Orion molecular cloud complex.
A Molecular Line Survey around Orion at Low Frequencies with the MWA
Publisher: American Astronomical Society
Date: 21-06-2018
Ionisation impact of high-mass stars on interstellar filaments
Publisher: EDP Sciences
Date: 24-01-2013
Water masers within the G 333.2 0.6 giant molecular cloud
Publisher: Cambridge University Press (CUP)
Date: 03-2007
DOI: 10.1017/S1743921307012720
Abstract: We report the results of a blind search for 22 GHz water masers in two regions, covering approximately half a square degree, within the G 333.2–0.6 giant molecular cloud. The complete search of the two regions was carried out with the 26 m Mount Pleasant radio telescope and resulted in the detection of nine water masers, five of which are new detections. Australia Telescope Compact Array (ATCA) observations of these detections have allowed us to obtain positions with arcsecond accuracy, allowing meaningful comparison with infrared and molecular data for the region. We find that for the regions surveyed there are more water masers than either 6.7 GHz methanol, or main-line OH masers. The water masers are concentrated towards the central axis of the star formation region, in contrast to the 6.7 GHz methanol masers which tend to be located near the periphery. The colours of the GLIMPSE point sources associated with the water masers are slightly less red than those associated with methanol masers. Statistical investigation of the properties of the 13 CO and 1.2 mm dust clumps with and without associated water masers shows that the water masers are associated with the more massive, denser and brighter 13 CO and 1.2 mm dust clumps. We present statistical models that can predict those 13 CO and 1.2 mm dust clumps likely to have associated water masers.
Observations and radiative transfer modelling of a massive dense cold core in G333
Publisher: Oxford University Press (OUP)
Date: 06-05-2011
Characterising the high-mass star forming filament G351.776–0.527 with Herschel and APEX dust continuum and gas observations
Publisher: EDP Sciences
Date: 2019
DOI: 10.1051/0004-6361/201833612
Abstract: G351.776-0.527 is among the most massive, closest, and youngest filaments in the inner Galactic plane and therefore it is an ideal laboratory to study the kinematics of dense gas and mass replenishment on a large scale. In this paper, we present far-infrared and submillimetre wavelength continuum observations combined with spectroscopic C 18 O (2–1) data of the entire region to study its temperature, mass distribution, and kinematics. The structure is composed of a main elongated region with an aspect ratio of ~23, which is associated with a network of filamentary structures. The main filament has a remarkably constant width of 0.2 pc. The total mass of the network (including the main filament) is ≥2600 M ⊙ , while we estimate a mass of ~2000 M ⊙ for the main structure. Therefore, the network harbours a large reservoir of gas and dust that could still be accreted onto the main structure. From the analysis of the gas kinematics, we detect two velocity components in the northern part of the main filament. The data also reveal velocity oscillations in C 18 O along the spine in the main filament and in at least one of the branches. Considering the region as a single structure, we find that it is globally close to virial equilibrium indicating that the entire structure is approximately in a stable state.
IAU volume 13 issue S332 Cover and Front matter
Publisher: Cambridge University Press (CUP)
Date: 03-2017
G351.77–0.51: ridge formation caught in the act
Publisher: EDP Sciences
Date: 2015
DOI: 10.1051/EAS/1575052
ABUNDANCES AND ISOTOPE RATIOS IN THE MAGELLANIC CLOUDS: THE STAR-FORMING ENVIRONMENT OF N 113
Publisher: American Astronomical Society
Date: 12-2008
A view of Large Magellanic Cloud H ii regions N159, N132, and N166 through the 345-GHz window
Publisher: Oxford University Press (OUP)
Date: 04-11-2015
The segregation of starless and protostellar clumps in the Hi-GALℓ= 224° region
Publisher: EDP Sciences
Date: 10-2016
High Mass Star Formation: Properties of NH$_3$ clumps in Southern Galactic Plane
Publisher: Cambridge University Press (CUP)
Date: 08-2016
DOI: 10.1017/S1743921316007638
Abstract: Massive stars are some of the most important objects in the Universe, shaping the evolution of galaxies, creating chemical elements, and hence shaping the evolution of the Universe. However, the processes by which they form, and how they shape their environment during their birth processes, are not well understood. We are using NH 3 data from the “The H 2 O Southern Galactic Plane Survey” (HOPS) to define the positions of dense cores/clumps of gas in the southern Galactic plane that are likely to form stars. We did a comparative study with different methods for finding clumps and found Fellwalker to be the best for this dataset. We detected ~ 500 clumps with mean kinetic temperature ~ 20 K and virial mass ~ 680 solar masses.
Supersonic turbulence in the cold massive core JCMT 18354���0649S���
Publisher: Oxford University Press (OUP)
Date: 21-11-2009
Intensity ratios for XDR/PDR identification
Publisher: Cambridge University Press (CUP)
Date: 08-2016
DOI: 10.1017/S1743921316007912
Abstract: The intensity ratios of HCO + /HCN and HNC/HCN (1-0) reveal the relative influence of star formation and active galactic nuclei (AGN) or black holes on the circum-nuclear gas of a galaxy, allowing the identification of X-ray dominated regions (XDRs) and Photon-dominated regions (PDRs). It is not always clear in the literature how this intensity ratio calculation has been, or should be performed. This paper discusses ratio calculation methods for interferometric data.
Spectral energy distribution modelling of southern candidate massive protostars using the Bayesian inference method
Publisher: Oxford University Press (OUP)
Date: 11-01-2009
ALMA OBSERVATIONS OF THE MASSIVE MOLECULAR OUTFLOW G331.512–0.103
Publisher: American Astronomical Society
Date: 14-08-2013
Turbulence in the G333 molecular cloud
Publisher: Cambridge University Press (CUP)
Date: 08-2006
DOI: 10.1017/S1743921307002177
Abstract: We are studying the molecular clouds in the region around G333.6-0.2 in a number of 3-mm transitions from different molecular species, to probe, among other things, the turbulent properties. The observations are being made by on-the-fly mapping with the 22-m diameter single-dish Mopra radio telescope. See Bains et al . (2006) and Cunningham et al . (2006 in these proceedings) for more details. During 2004 and 2005 we obtained 13 CO (1 – 0), C 18 O, CS (2 – 1) and C 34 S data. Using the different molecular tracers gives complementary information about the gas density structure, due to the different critical densities, and different isotopomers allows correction for optical depth effects.
ATOMS: ALMA three-millimeter observations of massive star-forming regions – II. Compact objects in ACA observations and star formation scaling relations
Publisher: Oxford University Press (OUP)
Date: 06-06-2020
Abstract: We report studies of the relationships between the total bolometric luminosity (Lbol or LTIR) and the molecular line luminosities of J = 1 − 0 transitions of H13CN, H13CO+, HCN, and HCO+ with data obtained from ACA observations in the ‘ATOMS’ survey of 146 active Galactic star-forming regions. The correlations between Lbol and molecular line luminosities $L^{\\prime }_{\\rm mol}$ of the four transitions all appear to be approximately linear. Line emission of isotopologues shows as large scatters in Lbol–$L^{\\prime }_{\\rm mol}$ relations as their main line emission. The log(Lbol/$L^{\\prime }_{\\rm mol}$) for different molecular line tracers have similar distributions. The Lbol-to-$L^{\\prime }_{\\rm mol}$ ratios do not change with galactocentric distances (RGC) and clump masses (Mclump). The molecular line luminosity ratios (HCN-to-HCO+, H13CN-to-H13CO+, HCN-to-H13CN, and HCO+-to-H13CO+) all appear constant against Lbol, dust temperature (Td), Mclump, and RGC. Our studies suggest that both the main lines and isotopologue lines are good tracers of the total masses of dense gas in Galactic molecular clumps. The large optical depths of main lines do not affect the interpretation of the slopes in star formation relations. We find that the mean star formation efficiency (SFE) of massive Galactic clumps in the ‘ATOMS’ survey is reasonably consistent with other measures of the SFE for dense gas, even those using very different tracers or examining very different spatial scales.
The Three-mm Ultimate Mopra Milky Way Survey. I. Survey Overview, Initial Data Releases, and First Results
Publisher: American Astronomical Society
Date: 05-10-2015
Molecular gas kinematics within the central 250 pc of the Milky Way
Publisher: Oxford University Press (OUP)
Date: 12-02-2016
DOI: 10.1093/MNRAS/STW121
High-Resolution Acta Observations of the Circumnuclear Molecular Clouds of Ngc 4945
Publisher: Springer Science and Business Media LLC
Date: 2005
Synthesis Imaging of Dense Molecular Gas in the N113 Hii Region of the Large Magellanic Cloud
Publisher: American Astronomical Society
Date: 20-09-2006
DOI: 10.1086/504968
THE THREE-mm ULTIMATE MOPRA MILKY WAY SURVEY. II. CLOUD AND STAR FORMATION NEAR THE FILAMENTARY MINISTARBURST RCW 106
Publisher: American Astronomical Society
Date: 05-10-2015
Footpoints of the giant molecular loops in the Galactic center region
Publisher: EDP Sciences
Date: 05-2018
DOI: 10.1051/0004-6361/201629065
Abstract: Aims. We aim to reveal the morphology, chemical composition, kinematics, and to establish the main processes prevalent in the gas at the footpoints of the giant molecular loops (GMLs) in the Galactic center region. Methods. Using the 22-m Mopra telescope, we mapped the M−3.8+0.9 molecular cloud, placed at the footpoints of a GML, in 3-mm range molecular lines. To derive the molecular hydrogen column density, we also observed the 13 CO(2 − 1) line at 1 mm using the 12-m APEX telescope. From the 3 mm observations 12 molecular species were detected, namely HCO + , HCN, H 13 CN, HNC, SiO, CS, CH 3 OH, N 2 H + , SO, HNCO, OCS, and HC 3 N. Results. Maps revealing the morphology and kinematics of the M−3.8+0.9 molecular cloud in different molecules are presented. We identify six main molecular complexes. We derive fractional abundances in 11 selected positions of the different molecules assuming local thermodynamical equilibrium. Conclusions. Most of the fractional abundances derived for the M−3.8+0.9 molecular cloud are very similar over the whole cloud. However, the fractional abundances of some molecules show significant difference with respect to those measured in the central molecular zone (CMZ). The abundances of the shock tracer SiO are very similar between the GMLs and the CMZ. The methanol emission is the most abundant species in the GMLs. This indicates that the gas is likely affected by moderate ~30 km s −1 or even high velocity (50 km s −1 ) shocks, consistent with the line profile observed toward one of the studied position. The origin of the shocks is likely related to the flow of the gas throughout the GMLs towards the footpoints.
A Search for biomolecules in Sagittarius B2 (LMH) with the Australia Telescope Compact Array
Publisher: Oxford University Press (OUP)
Date: 2007
Observations of HCN hyperfine line anomalies towards low- and high-mass star-forming cores
Publisher: Oxford University Press (OUP)
Date: 08-12-2011
The chemistry and kinematics of two molecular clouds near Sagittarius A*
Publisher: Oxford University Press (OUP)
Date: 09-08-2016
INFRARED DARK CLOUDS IN THE SMALL MAGELLANIC CLOUD?
Publisher: American Astronomical Society
Date: 03-09-2009
ASTE observations in the 345 GHz window towards the HII region N113 of the Large Magellanic Cloud
Publisher: EDP Sciences
Date: 27-11-2014
Physical and chemical conditions in methanol maser selected hot cores and UCHII regions
Publisher: Oxford University Press (OUP)
Date: 21-03-2009
Molecular line mapping of the giant molecular cloud associated with RCW 106 – II. Column density and dynamical state of the clumps
Publisher: Oxford University Press (OUP)
Date: 05-2008
The nuclear molecular clouds of NGC 4945
Publisher: Oxford University Press (OUP)
Date: 21-11-2005
The role of automated methods for filament finding in understanding the complex relationship between filaments, magnetic fields and star formation
Publisher: Cambridge University Press (CUP)
Date: 08-2018
DOI: 10.1017/S1743921319003132
Abstract: The discovery of the ubiquity of filaments in the interstellar medium in the last two decades has begged the question: “What role do filaments play in star formation?” Here we describe how our automated filament finding algorithms can combine with both magnetic field measurements and high-resolution observations of dense cores in these filaments, to provide a statistically large s le to investigate the effect of filaments on star formation. We find that filaments are likely actively accreting mass from the interstellar medium, explaining why some 60% of stars, and all massive stars, form “on-filament”.
Dense gas in nearby galaxies
Publisher: EDP Sciences
Date: 16-07-2004
Tracing H$_2$ Column Density with Atomic Carbon (C I) and CO Isotopologs
Publisher: American Astronomical Society
Date: 03-12-2014
Spectral imaging of the Central Molecular Zone in multiple 3-mm molecular lines
Publisher: Oxford University Press (OUP)
Date: 18-11-2011
Spectral imaging of the Sagittarius B2 region in multiple 3-mm molecular lines with the Mopra telescope
Publisher: Oxford University Press (OUP)
Date: 05-2008
Understanding star formation in molecular clouds
Publisher: EDP Sciences
Date: 19-02-2016
Tracing Multi-scale Magnetic Field Structure Using Multiple Chemical Tracers in Giant Molecular Clouds
Publisher: American Astronomical Society
Date: 18-10-2019
Spectral imaging of the Sagittarius B2 region in multiple 7-mm molecular lines
Publisher: Oxford University Press (OUP)
Date: 25-11-2011
Scaled up low-mass star formation in massive star-forming cores in the G333 giant molecular cloud
Publisher: Oxford University Press (OUP)
Date: 07-03-2016
DOI: 10.1093/MNRAS/STW525
Detection of SiO emission from a massive dense cold core
Publisher: Oxford University Press (OUP)
Date: 10-2007
Relative Alignment between the Magnetic Field and Molecular Gas Structure in the Vela C Giant Molecular Cloud Using Low- and High-density Tracers
Publisher: American Astronomical Society
Date: 19-06-2019
SpS1-From molecular clouds to massive stars
Publisher: Cambridge University Press (CUP)
Date: 11-2009
DOI: 10.1017/S1743921310010446
Abstract: The life cycles of massive stars have a major impact on the evolution of galaxies, while in turn, position in galaxy has a major impact on the efficiency and type of star formation which occurs in a molecular cloud (see e.g. Luna et al . 2006). However, exactly how massive stars form, on what timescales, and how they shape their environments during this active and energetic phase is poorly understood.
Molecular line mapping of the giant molecular cloud associated with RCW 106 - III. Multimolecular line mapping
Publisher: Oxford University Press (OUP)
Date: 11-05-2009
HOPS: The H$_2$O Southern Galactic Plane Survey
Publisher: EDP Sciences
Date: 2011
DOI: 10.1051/EAS/1152021
Search for High-Extinction Regions in the Small Magellanic Cloud
Publisher: Cambridge University Press (CUP)
Date: 11-2009
DOI: 10.1017/S1743921310010008
Abstract: We have applied the unsharp-masking technique to the 24 μm image of the SMC, obtained with the Spitzer , to search for high-extinction regions. Fifty-five candidate regions of high-extincion (namely high-contrast regions, HCRs) have been identified from the decremental contrast image. HCRs have a size of 8 - 14 pc and a peak contrast at 24 μm of 2 - 2.5%. To constrain physical properties of HCRs, we have performed observations of NH 3 , N 2 H + , HNC, HCO + , and HCN toward one of the HCRs, HCR LIRS36–east, using the ATCA and the Mopra telescope. No molecular line emission detected, but upper limits to column densities of molecular species suggest that HCRs are moderately dense with n ~ 10 3 cm −3 . Two interesting properties of HCRs are shown below.
Ammonia towards dust clumps in the giant molecular cloud associated with RCW 106
Publisher: Cambridge University Press (CUP)
Date: 08-2013
DOI: 10.1017/S1743921313000318
Abstract: High-mass stars are known to be born within giant molecular clouds (GMCs) However, the exact processes involved in forming a high-mass star are still not well understood. It is clear that high-mass stars do not form in isolation, and that the processes surrounding high-mass star formation may affect the environment of the entire molecular cloud. We are studying the GMC associated with RCW 106 (G333), which is one of the most active massive-star formation regions in the Galactic plane. This GMC, located at l = 333° b = − 0.5°, has been mapped in over 20 molecular line transitions with the Mopra radio telescope (83-110 GHz), in Australia, and with the Swedish-ESO Submillimeter Telescope (SEST) in the 1.2 mm cool dust continuum. The region is also within the Spitzer GLIMPSE infrared survey (3.6, 4.5, 5.8, and 8.0 μ m ) area. We have decomposed the dust continuum using a clump-finding algorithm (CLUMPFIND), and are using the multiple molecular line traditions from the Mopra radio telescope to classify the type and stage of star formation taking place therein. Having accurate physical temperatures of the star forming clumps is essential to constrain other parameters to within useful limits. To achieve this, we have obtained pointed NH 3 observations from the Tidbinbilla 70-m radio telescope, in Australia, towards these clumps.
SPLASH: the Southern Parkes Large-Area Survey in Hydroxyl - first science from the pilot region
Publisher: Oxford University Press (OUP)
Date: 07-02-2014
DOI: 10.1093/MNRAS/STU032
H$_2$O Southern Galactic Plane Survey (HOPS): Paper III - properties of dense molecular gas across the inner Milky Way
Publisher: Oxford University Press (OUP)
Date: 24-05-2017
A search for 22-GHz water masers within the giant molecular cloud associated with RCW 106
Publisher: Oxford University Press (OUP)
Date: 11-05-2007
A Spitzer Space Telescope survey of massive young stellar objects in the G333.2−0.4 giant molecular cloud
Publisher: Oxford University Press (OUP)
Date: 09-11-2011
Do dense molecular cores with broad emission spectra at |l| ≈ 5.4°, |b| ≈ 0.4° trace the Galactic bar? A multimolecular line study from HOPS
Publisher: Oxford University Press (OUP)
Date: 03-02-2020
Abstract: We used NH$\rm _3$(1,1) data from the H$\rm _2$O Southern Galactic Plane Survey (HOPS) between −60° & l & −2.7° and 3.9° & l & 30° and |b| & 0.5° to identify dense molecular regions/clumps of the Milky Way Galaxy that are likely to form high-mass stars. We identified ∼500 such clumps and in this paper we report on 14 of these clumps near the Central Molecular Zone that show broad emission spectral lines (with observed velocity widths between 19.8 and 47.6 km s−1 corresponding to intrinsic velocity widths between 7.1 and 25.2 km s−1). We find that these clumps are grouped into three clusters of dense molecular cores centred at l ≈ 5.4°, −5.4°, and −10°. We name them ‘Cluster-1’, ‘Cluster-2’ (also known as ‘Bania’s Clump 1’), and ‘Cluster-3’. We find that the same clumps exhibit broad emission spectra for other molecular lines – NH$\rm _3$(2,2), (3,3), and HC3N(3 − 2). The antisymmetry of Cluster-1 and Cluster-2 in the l − b plane, and the large velocity dispersion of each clump in these two clusters suggest that clusters 1 and 2 may be associated with the Galactic bar potential x−1 orbits. Our assessments show that the clumps of these three clusters host hot gases and their emission-line broadening are associated with shock heating. We find that Cluster-3 is likely to be undergoing high-mass star formation, as suggested by the presence of emission from H$\rm _2$O maser and radio recombination line (H69α) from HOPS.
Profiling young massive stars
Publisher: Cambridge University Press (CUP)
Date: 03-2007
DOI: 10.1017/S1743921307012665
Abstract: We present the results of spectral energy distribution analysis for 162 of the 405 sources reported in the SIMBA survey of Hill et al . (2005). The fits reveal source specific parameters including: the luminosity, mass, temperature, H 2 number density, the surface density and the luminosity-to-mass ratio. Each of these parameters are examined with respect to the four classes of source present in the s le. Obvious luminosity and temperature distinctions exist between the mm-only cores and those cores with methanol maser and/or radio continuum emission, with the former cooler and less luminous than the latter. The evidence suggests that the mm-only cores are a precursor to the methanol maser in the formation of massive stars. The mm-only cores comprise two distinct populations distinguished by temperature. Analysis and conclusions about the nature of the cool-mm and warm-mm cores comprising the mm-only population are drawn.
ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Detection of Extremely High-density Compact Structure of Prestellar Cores and Multiple Substructures Within
Publisher: American Astronomical Society
Date: 19-01-2021
Millimetre continuum observations of southern massive star formation regions – II. SCUBA observations of cold cores and the dust grain emissivity index (β)
Publisher: Oxford University Press (OUP)
Date: 13-04-2006
An ATCA survey of Sagittarius B2 at 7 mm: chemical complexity meets broad-band interferometry
Publisher: Oxford University Press (OUP)
Date: 10-08-2015
Removing Visual Bias in Filament Identification: A New Goodness-of-fit Measure
Publisher: American Astronomical Society
Date: 09-05-2017
Multi-generation massive star-formation in NGC 3576
Publisher: EDP Sciences
Date: 09-07-2009
High-mass star-forming cloud G0.38+0.04 in the Galactic center dust ridge contains H$_2$CO and SiO masers
Publisher: EDP Sciences
Date: 19-11-2015
Triggered star formation on the borders of the Galactic Hii region RCW 82
Publisher: EDP Sciences
Date: 22-12-2008
The Mopra DQS survey of the G333 region
Publisher: Cambridge University Press (CUP)
Date: 08-2006
DOI: 10.1017/S1743921307001925
Abstract: Any successful model of star formation must be able to explain the low star forming efficiency of molecular clouds in our Galaxy. If the collapse of gas is regulated only by gravity, then the star formation rate should be orders of magnitude larger than the 1 M per year within our galaxy. The standard model invokes magnetic fields to slow down the rate of collapse, but does not explain star formation in cluster mode, or the lack of observed variations in the chemistry of molecular clouds if they are long-lived entities.
Analysis of Hydrogen Cyanide Hyperfine Spectral Components towards Star Forming Cores
Publisher: Walter de Gruyter GmbH
Date: 2011
Abstract: Although hydrogen cyanide has become quite a common molecular tracing species for a variety of astrophysical sources, it, however, exhibits dramatic non-LTE behaviour in its hyperfine line structure. In idual hyperfine components can be strongly boosted or suppressed. If these so-called hyperfine line anomalies are present in the HCN rotational spectra towards low or high mass cores, this will affect the interpretation of various physical properties such as the line opacity and excitation temperature in the case of low mass objects and infall velocities in the case of their higher mass counterparts. Anomalous line ratios are present either through the relative strengths of neighboring hyperfine lines or through the varying widths of hyperfine lines belonging to a particular rotational line. This work involves the first observational investigation of these anomalies in two HCN rotational transitions, J=1→0 and J=3→2, towards both low mass starless cores and high mass protostellar objects. The degree of anomaly in these two rotational transitions is considered by computing the ratios of neighboring hyperfine lines in in idual spectra. Results indicate some degree of anomaly is present in all cores considered in our survey, the most likely cause being line overlap effects among hyperfine components in higher rotational transitions.
Dense circumnuclear molecular gas in starburst galaxies
Publisher: Oxford University Press (OUP)
Date: 10-02-2016
Molecular line mapping of the giant molecular cloud associated with RCW 106 - I. $^13$CO
Publisher: Oxford University Press (OUP)
Date: 21-04-2006
Measuring Filament Orientation: A New Quantitative, Local Approach
Publisher: American Astronomical Society
Date: 31-08-2017
The Properties of Planck Galactic Cold Clumps in the L1495 Dark Cloud
Publisher: American Astronomical Society
Date: 02-04-2018
Millimetre molecular lines in Planck cold clumps
Publisher: Cambridge University Press (CUP)
Date: 08-2015
DOI: 10.1017/S1743921316004440
Abstract: Galactic cold clumps have been identified from the Planck data (Planck Collaboration, 2011a, 2011b, 2015) as 10 342 cold (7 - 19 K) sources that stand out against a warmer environment, with the Early Cold Cores as a subs le of 915 most reliable detections. There is CO emission associated with the Planck Cold Clumps (PCCs), which has been observed with ground-based radio telescopes at higher resolution (Wu et al . 2012, Liu et al . 2014). A subset of PCCs have also been observed with Herschel at higher resolution (Juvela et al. 2012). A southern sub-s le of the PCCs has been observed with the Mopra 22-m telescope to study the molecular gas. The Mopra telescope has 3-mm, 7-mm and 12-mm bands, with broadband correlator configuration 8-GHz wide with 0.27-MHz channels, or multiple zoom bands 137-MHz wide with 33-KHz channels, within the 8 GHz. During the 2013 southern winter season we observed 10 clumps. This included observations in the 3-mm band of 12 CO, 13 CO and C 18 O and lines around 89 GHz (e.g. HCN, HCO + and HNC), in the 7-mm band (e.g. CS) and in the 12-mm band (e.g. NH 3 ). These observations were heterogenous, with sources selected by LST in gaps between observations of other projects, and band chosen by weather (i.e. in conditions unsuitable for higher frequencies, lower frequency bands were observed). During the 2014 season we observed 34 positions in 22 clumps, with zoom mode observations of lines around 89 GHz. This was a more well-defined s le of sources. The mapping of the CO lines shows good spatial correlation of the CO with the dust column density The CO isotoplogues show high optical depth in 12 CO and 13 CO. The lines of HCN, HCO + and HNC are weak, but detected in many of the 2014 s le. We are modelling the line results to determine column densities, excitation temperatures and abundances, using tools such as radex (van der Tak et al. 2007).
Exploring the pattern of the Galactic HI foreground of GRBs with the ATCA
Publisher: Oxford University Press (OUP)
Date: 30-08-2019
Abstract: The afterglow of a gamma ray burst (GRB) can give us valuable insight into the properties of its host galaxy. To correctly interpret the spectra of the afterglow we need to have a good understanding of the foreground interstellar medium (ISM) in our own Galaxy. The common practice to correct for the foreground is to use neutral hydrogen (H i) data from the Leiden/Argentina/Bonn (LAB) survey. However, the poor spatial resolution of the single dish data may have a significant effect on the derived column densities. To investigate this, we present new high-resolution H i observations with the Australia Telescope Compact Array (ATCA) towards 4 GRBs. We combine the interferometric ATCA data with single dish data from the Galactic All Sky Survey (GASS) and derive new Galactic H i column densities towards the GRBs. We use these new foreground column densities to fit the Swift XRT X-ray spectra and calculate new intrinsic hydrogen column density values for the GRB host galaxies. We find that the new ATCA data shows higher Galactic H i column densities compared to the previous single dish data, which results in lower intrinsic column densities for the hosts. We investigate the line of sight optical depth near the GRBs and find that it may not be negligible towards one of the GRBs, which indicates that the intrinsic hydrogen column density of its host galaxy may be even lower. In addition, we compare our results to column densities derived from far-infrared data and find a reasonable agreement with the H i data.
Star Formation Laws in Both Galactic Massive Clumps and External Galaxies: Extensive Study with Dust Coninuum, HCN (4-3), and CS (7-6)
Publisher: American Astronomical Society
Date: 22-09-2016
Large Scale Structure and Turbulence: The Mopra G333 Survey
Publisher: EDP Sciences
Date: 2008
DOI: 10.1051/EAS:0831003
Gas Content in the GMC G333: hierarchical structure of turbulence
Publisher: Cambridge University Press (CUP)
Date: 08-2012
DOI: 10.1017/S1743921313000306
Abstract: We present our preliminary results on the application of dendrogram statistics to the carbon monoxide PPV map of the giant molecular cloud G333. We obtain the dendrograms at various merging levels and found the clustering of branches is independent from the merging levels. The statistics of intensity distributions show gravity is possibly significant in this cloud and the gas may be sonic. Application of this method to other molecular lines data are required for further analysis of the cloud properties.
Millimetre continuum observations of southern massive star formation regions -- I. SIMBA observations of cold cores
Publisher: Oxford University Press (OUP)
Date: 21-10-2005
VLBI OH maser polarimetry with the Australian Long Baseline Array: the star-forming region G340.054 0.244
Publisher: Cambridge University Press (CUP)
Date: 03-2007
DOI: 10.1017/S1743921307012574
Abstract: Until recently, high spatial resolution full Stokes maser polarimetry was the sole domain of northern interferometers and a wealth of sources in the far south remained unexplored due to a lack of suitable instrumentation having both high spatial and high velocity resolution. The Australia Telescope Long Baseline Array (LBA) has now switched to disk-based software correlation, permitting full Stokes observing in spectral line mode with velocity channels which are sufficiently narrow to s le usefully the polarization structure. To illustrate the utility of this valuable addition to radio astronomy, we present preliminary results of the first such polarimetric observation, the subject of which are the OH masers in the star-forming region G340.054–0.244.
Physical characterization of southern massive star-forming regions using Parkes NH3 observations
Publisher: Oxford University Press (OUP)
Date: 03-2010
Infall, outflow, and turbulence in massive star-forming cores in the G333 giant molecular cloud
Publisher: Oxford University Press (OUP)
Date: 04-09-2015
Spectral imaging of the central molecular zone in multiple 7-mm molecular lines
Publisher: Oxford University Press (OUP)
Date: 22-05-2013
DOI: 10.1093/MNRAS/STT717
The nature of the Stingray nebula from radio observations
Publisher: Oxford University Press (OUP)
Date: 11-06-2018
First Data Release of the ESO-ARO Public Survey SAMPLING—SMT “All-sky” Mapping of Planck Interstellar Nebulae in the Galaxy
Publisher: American Astronomical Society
Date: 04-01-2018
MALT-45: a 7 mm survey of the southern Galaxy - I. Techniques and spectral line data
Publisher: Oxford University Press (OUP)
Date: 27-02-2015
DOI: 10.1093/MNRAS/STV178
Molecular line mapping of the giant molecular cloud associated with RCW 106-IV. Ammonia towards dust emission
Publisher: Oxford University Press (OUP)
Date: 24-04-2014
DOI: 10.1093/MNRAS/STU568
A first look for molecules between 103 and 133 MHz using the Murchison Widefield Array
Publisher: Oxford University Press (OUP)
Date: 20-07-2017
Astrochemical Properties of Planck Cold Clumps
Publisher: American Astronomical Society
Date: 06-02-2017
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