A Holistic Perspective on the Dynamics of G035.39-00.33: The Interplay between Gas and Magnetic Fields

Liu, Tie; Li, Pak Shing; Juvela, M.; Kim, Kee‐Tae; Evans, Neal J.; Francesco, James Di; Liu, Sheng-Yuan; Yuan, Jinghua; Tatematsu, Ken’ichi; Zhang, Qizhou; Ward-Thompson, Derek; Fuller, G. A.; Goldsmith, Paul F.; Koch, Patrick M.; Sanhueza, Patricio; Ristorcelli, I.; Kang, Sung-Ju; Chen, Huei-Ru Vivien; Hirano, Naomi; Wu, Yuefang; Sokolov, Vlas; Lee, Chang Won; White, G. J.; Wang, Ke; Eden, David; Di, Li; Thompson, M. A.; Pattle, Kate; Soam, Archana; Nasedkin, E.; Kim, Jong-Soo; Kim, Gwanjeong; Lai, Shih-Ping; Park, Geumsook; Qiu, Keping; Zhang, Chuan-Peng; Alina, D.; Eswaraiah, Chakali; Falgarone, É.; Fich, M.; Greaves, J. S.; Gu, Qilao; Kwon, Woojin; Li, Hua-bai; Malinen, J.; Montier, L.; Parsons, Harriet; Qin, Sheng-Li; Rawlings, Mark G.; Ren, Zhiyuan; Tang, Mengyao; Tang, Ya-Wen; Tóth, L. V.; Wang, Jiawei; Wouterloot, J. G. A.; Yi, Hee-Weon; Zhang, H.-W.

doi:10.3847/1538-4357/aac025

Cited by 74 publications

(65 citation statements)

References 133 publications

(182 reference statements)

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“…Sanhueza et al (2010) also observed these cores and found molecular outflows associated with cores G34-MM1, MM2, MM3, and MM4. G35 is a filament similar to G34 with several embedded lowluminosity massive protostars (Nguyen Luong et al, 2011) and massive starless clumps (Liu et al, 2018a). A network of filaments covering a broad range of densities is also revealed in G35.…”

Section: Introductionmentioning

confidence: 80%

“…Due to low angular resolution (e.g., ∼ 5 ′ with Planck) or high dust extinction (optical or near-infrared polarimetery), previous studies of magnetic fields in filamentary clouds have been mostly limited to nearby clouds. So far, magnetic fields have only been investigated in a few infrared dark clouds (Pillai et al, 2015;Liu et al, 2018a;Juvela et al, 2018;Liu et al, 2018b). Additional observations with higher angular resolution towards filamentary clouds and cores are still needed.…”

Section: Introductionmentioning

confidence: 99%

“…To this end, we are conducting a series of dust polarization observations toward the brightest filaments identified in the JCMT legacy survey of ∼1000 Planck Galactic Cold Clumps (PGCCs), called SCOPE (SCUBA-2 Continuum Observations of Pre-protostellar Evolution; Liu et al, 2018c;Eden et al, 2019), with the POL-2 polarimeter at the JCMT. The observational results of two PGCCs, G35.49-0.31 (hereafter G35) and G9.62+0.19 (hereafter G9) are published in Liu et al (2018a) and Liu et al (2018b), respectively.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic Fields in the Infrared Dark Cloud G34.43+0.24

Soam

Liu

Andersson

et al. 2019

ApJ

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We present the B-fields mapped in IRDC G34.43+0.24 using 850 µm polarized dust emission observed with the POL-2 instrument at JCMT. We examine the magnetic field geometries and strengths in the northern, central, and southern regions of the filament. The overall field geometry is ordered and aligned closely perpendicular to the filament's main axis, particularly in regions containing the central clumps MM1 and MM2, whereas MM3 in the north has field orientations aligned with its major axis. The overall field orientations are uniform at large (POL-2 at 14 ′′ and SHARP at 10 ′′ ) to small scales (TADPOL at 2.5 ′′ and SMA at 1.5 ′′ ) in the MM1 and MM2 regions. SHARP/CSO observations in MM3 at 350 µm from Tang et al. show a similar trend as seen in our POL-2 observations. TADPOL observations demonstrate a well-defined field geometry in MM1/MM2 consistent with MHD simulations of accreting filaments. We obtained a plane-of-sky magnetic field strength of 470±190 µG, 100±40 µG, and 60±34 µG in the central, northern and southern regions of G34, respectively, using the updated Davis-Chandrasekhar-Fermi relation. The estimated value of field strength, combined with column density and velocity dispersion values available in the literature, suggests G34 to be marginally critical with criticality parameter λ values 0.8±0.4, 1.1±0.8, and 0.9±0.5 in the central, northern, and southern regions, respectively. The turbulent motions in G34 are sub-Alfvénic with Alfvénic Mach numbers of 0.34±0.13, 0.53±0.30, and 0.49±0.26 in the three regions. The observed aligned B-fields in G34.43+0.24 are consistent with theoretical models suggesting that B-fields play an important role in guiding the contraction of the cloud driven by gravity.

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Section: Introductionmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Magnetic Fields in the Infrared Dark Cloud G34.43+0.24

Soam

Liu

Andersson

et al. 2019

ApJ

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“…However, lack of 24 and 70 µm emission does not guarantee a complete absence of star formation activity (e.g., Tan et al 2016;Feng et al 2016b). Several studies have investigated the kinematics and filamentary structure of IRDCs (Busquet et al 2013;Henshaw et al 2014Henshaw et al , 2016Foster et al 2014;Liu et al 2014;Ragan et al 2015;Contreras et al 2016;Lu et al 2018;Liu et al 2018c;Chen et al 2019), their chemistry (Sanhueza et al 2012Sakai et al 2008Sakai et al , 2012Sakai et al , 2015Hoq et al 2013;Miettinen 2014;Vasyunina et al 2014;Feng et al 2016a;Kong et al 2016;Tatematsu et al 2017), molecular outflow content (Sanhueza et al 2010;Wang et al 2011Wang et al , 2014Lu et al 2015;Kong et al 2019), infall (Sanhueza et al 2010;Liu et al 2018a), magnetic fields (Pillai et al 2015;Beuther et al 2018a;Liu et al 2018a;Tang et al 2019), and in the more evolved ones, ultracompact (UC) H ii regions (Battersby et al 2010;Avison et al 2015), thermal ionized jets (Rosero et al 2014(Rosero et al , 2016(Rosero et al , 2019, hot cores…”

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confidence: 99%

The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). I. Pilot Survey: Clump Fragmentation

Sanhueza

Contreras

et al. 2019

ApJ

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The ALMA Survey of 70 µm dark High-mass clumps in Early Stages (ASHES) has been designed to systematically characterize the earliest stages and to constrain theories of high-mass star formation. A deep understanding of highmass star formation requires the study of the clustered mode, which is the most commonly found in nature. A total of 12 massive (>500 M ), cold (≤15 K), 3.6-70 µm dark prestellar clump candidates, embedded in infrared dark clouds (IRDCs), were carefully selected in the pilot survey to be observed with the Atacama Large Millimeter/sub-millimeter Array (ALMA). Exploiting the unique capabilities of ALMA, we have mosaiced each clump (∼1 arcmin 2 ) in dust continuum and line emission with the 12 m, 7 m, and Total Power arrays at 224 GHz (1.34 mm), resulting in ∼1. 2 angular resolution (∼4800 AU at the average source distance of 4 kpc). As the first paper of the series, we concentrate on the dust continuum emission to reveal the clump fragmentation. We have detected a total of 294 cores, from which 84 (29%) are categorized as protostellar based on outflow activity or "warm core" line emission. The remaining 210 (71%) are considered prestellar core candidates. The number of detected cores is independent of the mass sensitivity range of the observations and, on average, more massive clumps tend to form more cores. We find no correlation between the mass of the host clump and the most massive embedded core. We find a large population of low-mass (<1 M ) cores and no high-mass (>30 M ) prestellar cores. The most massive prestellar core has a mass of 11 M . From the prestellar core mass function, we derive a power law index of 1.17 ± 0.10, slightly shallower than the Salpeter index of 1.35. We have used the minimum spanning tree technique to characterize the separation between cores and their spatial distribution, and to derive mass segregation ratios. While there is a range of core masses and core separations detected in the sample, the mean separation and mean mass of cores per clump are well explained

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“…The PGCC provides a statistically significant sample to study these questions observationally, although the Planck resolution limits the investigations to structures that are typically much larger than an individual cloud core. However, polarisation of selected PGCCs has already been studied at higher resolution with the SCUBA-2 POL-2 instrument at JCMT (Liu et al 2018c;Juvela et al 2018a;Liu et al 2018b), and many more will be covered by ongoing surveys .…”

Section: Introductionmentioning

confidence: 99%

Synthetic observations of dust emission and polarisation of Galactic cold clumps

Juvela

Padoan

Ristorcelli

et al. 2019

A&A

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Context. The Planck Catalogue of Galactic Cold Clumps (PGCC) contains over 13000 sources that are detected based on their cold dust signature. They are believed to consist of a mixture of quiescent, pre-stellar, and already star-forming objects within molecular clouds. Aims. We extracted PGCC-type objects from cloud simulations and examined their physical and polarisation properties. The comparison with the PGCC catalogue helps to characterise the properties of this large sample of Galactic objects and, conversely, provides valuable tests for numerical simulations of large volumes of the interstellar medium and the evolution towards pre-stellar cores. Methods. We used several magnetohydrodynamical (MHD) simulation snapshots to define the density field of our model clouds. Sub-millimetre images of the surface brightness and polarised signal were obtained with radiative transfer calculations. We examined the statistics of synthetic cold clump catalogues extracted with methods similar to the PGCC. We also examined the variations of the polarisation fraction p in the clumps. Results. The clump sizes, aspect ratios, and temperatures in the synthetic catalogue are similar to the PGCC. The fluxes and column densities of synthetic clumps are smaller by a factor of a few. Rather than with an increased dust opacity, this could be explained by increasing the average column density of the model by a factor of two to three, close to N(H) = 10 22 cm 2 . When the line of sight is parallel to the mean magnetic field, the polarisation fraction tends to increase towards the clump centres, which is contrary to observations. When the field is perpendicular, the polarisation fraction tends to decrease towards the clumps, but the drop in p is small (e.g. from p ∼8% to p ∼7%). Conclusions. Magnetic field geometry reduces the polarisation fraction in the simulated clumps by only ∆p ∼1% on average. The larger drop seen towards the actual PGCC clumps therefore suggests some loss of grain alignment in the dense medium, such as predicted by the radiative torque mechanism. The statistical study is not able to quantify dust opacity changes at the scale of the PGCC clumps.

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A Holistic Perspective on the Dynamics of G035.39-00.33: The Interplay between Gas and Magnetic Fields

Cited by 74 publications

References 133 publications

Magnetic Fields in the Infrared Dark Cloud G34.43+0.24

Magnetic Fields in the Infrared Dark Cloud G34.43+0.24

The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). I. Pilot Survey: Clump Fragmentation

Synthetic observations of dust emission and polarisation of Galactic cold clumps

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