Structural and Dynamical Analysis of 0.1 pc Cores and Filaments in the 30 Doradus-10 Giant Molecular Cloud

Indebetouw, R.; Wong, Tony; Chen, C.-H. Rosie; Kepley, Amanda A.; Lebouteiller, V.; Madden, S.; Oliveira, J. M.

doi:10.3847/1538-4357/ab5db7

Cited by 17 publications

(17 citation statements)

References 65 publications

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“…In contrast to the stellar population and PMS/YSO studies, available molecular gas maps of the 30 Dor region have much poorer angular resolution (10 pc; Johansson et al 1998;Minamidani et al 2008;Wong et al 2011;Kalari et al 2018;Okada et al 2019), aside from previously published data from the Atacama Large Millimeter/submillimeter Array (ALMA) covering a relatively small (12 × 12 pc) area (Indebetouw et al 2013(Indebetouw et al , 2020. To address these limitations, we have conducted new observations with ALMA, exploiting the array's unique capability to obtain a sensitive, high-resolution (1 75 beam) map of the giant molecular cloud complex across an extent of ∼100 pc using the CO J = 2-1 and 13 CO J = 2-1 transitions.…”

Section: Introductionmentioning

confidence: 99%

The 30 Doradus Molecular Cloud at 0.4 pc Resolution with the Atacama Large Millimeter/submillimeter Array: Physical Properties and the Boundedness of CO-emitting Structures

Wong

Oudshoorn

Eliyahu

et al. 2022

ApJ

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We present results of a wide-field (approximately 60 × 90 pc) Atacama Large Millimeter/submillimeter Array mosaic of CO(2–1) and 13CO(2–1) emission from the molecular cloud associated with the 30 Doradus star-forming region in the Large Magellanic Cloud (LMC). Three main emission complexes, including two forming a bow-tie-shaped structure extending northeast and southwest from the central R136 cluster, are resolved into complex filamentary networks. Consistent with previous studies, we find that the central region of the cloud has higher line widths at a fixed size relative to the rest of the molecular cloud and to other LMC clouds, indicating an enhanced level of turbulent motions. However, there is no clear trend in gravitational boundedness (as measured by the virial parameter) with distance from R136. Structures observed in 13CO are spatially coincident with filaments and are close to a state of virial equilibrium. In contrast, 12CO structures vary greatly in virialization, with low CO surface brightness structures outside of the main filamentary network being predominantly unbound. The low surface brightness structures constitute ∼10% of the measured CO luminosity; they may be shredded remnants of previously star-forming gas clumps, or alternatively the CO-emitting parts of more massive, CO-dark structures.

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Section: Introductionmentioning

confidence: 99%

The 30 Doradus Molecular Cloud at 0.4 pc Resolution with the Atacama Large Millimeter/submillimeter Array: Physical Properties and the Boundedness of CO-emitting Structures

Wong

Oudshoorn

Eliyahu

et al. 2022

ApJ

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“…The mass estimate when using the (1-0) lines is higher than our fitted RADEX (by an average factor of 1.66±0.19), which is harder to explain though not unprecedented (Indebetouw et al 2020). One way this could happen is if the 12 CO is not actually optically thick, which would make the LTE T ex estimate too low and shift the optical depth estimate higher.…”

Section: Lte Methodsmentioning

confidence: 61%

“…However, these calculations break down if 12 CO becomes optically thin, or if either line's level population is not well described by a Boltzmann distribution. Studies have shown regimes in which the LTE calculations overestimate the column density by up to a factor of two in bright (T B > 40 K) clouds (Indebetouw et al 2020), and underestimate the mass by up to a factor of 7 when the 13 CO becomes sub-thermally excited (Castets et al 1990;Padoan et al 2000;Heyer & Dame 2015). Assuming LTE also requires that the density is sufficiently high such that the excitation is entirely governed by temperature, meaning that any dependence on density drops out of the equations and so cannot be solved for.…”

Section: Introductionmentioning

confidence: 99%

Physical Conditions in the LMC's Quiescent Molecular Ridge: Fitting Non-LTE Models to CO Emission; Data Cubes

Finn,

Indebetouw,

Johnson

et al. 2021

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The Molecular Ridge in the LMC extends several kiloparsecs south from 30 Doradus, and it contains ∼ 30% of the molecular gas in the entire galaxy. However, the southern end of the Molecular Ridge is quiescent-it contains almost no massive star formation, which is a dramatic decrease from the very active massive star-forming regions 30 Doradus, N159, and N160. We present new ALMA and APEX observations of the Molecular Ridge at a resolution as high as ∼16 (∼3.9 pc) with molecular lines 12 CO(1-0), 13 CO(1-0), 12 CO(2-1), 13 CO(2-1), and CS(2-1). We analyze these emission lines with our new multi-line non-LTE fitting tool to produce maps of T kin , n H2 , and N CO across the region based on models from RADEX. Using simulated data for a range of parameter space for each of these variables, we evaluate how well our fitting method can recover these physical parameters for the given set of molecular lines. We then compare the results of this fitting with LTE and X CO methods of obtaining mass estimates and how line ratios correspond with physical conditions. We find that this fitting tool allows us to more directly probe the physical conditions of the gas and estimate values of T kin , n H2 , and N CO that are less subject to the effects of optical depth and line-of-sight projection than previous methods. The fitted n H2 values show a strong correlation with the presence of YSOs, and with the total and average mass of the associated YSOs. Typical star formation diagnostics, such as mean density, dense gas fraction, and virial parameter do not show a strong correlation with YSO properties.

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“…Only recently, this situation has begun to change (with a handful of exceptions, e.g. Hamedani Golshan et al 2021;Sewilo 2021;Shimonishi et al 2021;Indebetouw et al 2020, describing observations of molecular cores in the Magellanic Clouds). Further afield, ALMA (Atacama Large Millimeter Array) and 𝐻𝑆𝑇 (Hubble Space Telescope), respectively, now allow us to image the high resolution (1 ≈ 50 pc at 10 Mpc) distribution of the molecular ISM at GMC scales across entire galaxies and (in the same targets) allow us to inventory clusters and luminous stars an order of magnitude in size smaller yet.…”

Section: Introductionmentioning

confidence: 99%

PHANGS-HST: New Methods for Star Cluster Identification in Nearby Galaxies

Thilker,

Whitmore,

Lee

et al. 2021

Preprint

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We present an innovative and widely applicable approach for the detection and classification of stellar clusters, developed for the PHANGS-HST Treasury Program, an 𝑁𝑈𝑉-to-𝐼 band imaging campaign of 38 spiral galaxies. Our pipeline first generates a unified master source list for stars and candidate clusters, to enable a self-consistent inventory of all star formation products. To distinguish cluster candidates from stars, we introduce the Multiple Concentration Index (MCI) parameter, and measure inner and outer MCIs to probe morphology in more detail than with a single, standard concentration index (CI). We improve upon cluster candidate selection, jointly basing our criteria on expectations for MCI derived from synthetic cluster populations and published cluster catalogues, yielding model and empirical selection regions (respectively). Selection purity (confirmed clusters versus candidates, assessed via humanbased classification) is high (up to 70%) for moderately luminous sources in the empirical selection region, and somewhat lower overall (outside the region or fainter). The number of candidates rises steeply with decreasing luminosity, but pipeline-integrated Machine Learning (ML) classification prevents this from being problematic. We quantify the performance of our PHANGS-HST methods in comparison to LEGUS for a sample of four galaxies in common to both surveys, finding overall agreement with 50-75% of human verified star clusters appearing in both catalogues, but also subtle differences attributable to specific choices adopted by each project. The PHANGS-HST ML-classified Class 1 or 2 catalogues reach ∼ 1 magnitude fainter, ∼ 2× lower stellar mass, and are 2−5× larger in number, than attained in the human classified samples.

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Structural and Dynamical Analysis of 0.1 pc Cores and Filaments in the 30 Doradus-10 Giant Molecular Cloud

Cited by 17 publications

References 65 publications

The 30 Doradus Molecular Cloud at 0.4 pc Resolution with the Atacama Large Millimeter/submillimeter Array: Physical Properties and the Boundedness of CO-emitting Structures

The 30 Doradus Molecular Cloud at 0.4 pc Resolution with the Atacama Large Millimeter/submillimeter Array: Physical Properties and the Boundedness of CO-emitting Structures

Physical Conditions in the LMC's Quiescent Molecular Ridge: Fitting Non-LTE Models to CO Emission; Data Cubes

PHANGS-HST: New Methods for Star Cluster Identification in Nearby Galaxies

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