CN Zeeman observations of the NGC 2264-C protocluster

Maury, A.; Wiesemeyer, H.; Thum, C.

doi:10.1051/0004-6361/201219148

Cited by 6 publications

(6 citation statements)

References 44 publications

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“…Overall, there is a clear distinction between the two magnetized models (MU2 and MU10) and the quasi-hydro MU200 model. As expected theoretically, as soon as a magnetic field is taken into account, with field strengths in the range of what is actually observed (e.g., Falgarone et al 2008;Crutcher et al 2010;Maury et al 2012), the picture changes dramatically.…”

Section: Emission Mapssupporting

confidence: 71%

Synthetic observations of first hydrostatic cores in collapsing low-mass dense cores

Commerçon¹,

Levrier²,

Maury³

et al. 2012

A&A

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Context. First hydrostatic cores are predicted by theories of star formation, but their existence has never been demonstrated convincingly by (sub)millimeter observations. Furthermore, the multiplicity in the early phases of the star formation process is poorly constrained. Aims. The purpose of this paper is twofold. First, we seek to provide predictions for ALMA dust continuum emission maps from early Class 0 objects. Second, we show to what extent ALMA will be able to probe the fragmentation scale in these objects. Methods. Following our companion paper, we post-processed three state-of-the-art radiation-magneto-hydrodynamic 3D adaptive mesh refinement calculations to compute the emanating dust emission maps. We then produced synthetic ALMA observations of the dust thermal continuum from first hydrostatic cores. Results. We present the first synthetic ALMA observations of dust continuum emission from the first hydrostatic cores. We analyze the results given by the different bands and configurations and we discuss for which combinations of the two the first hydrostatic cores would most likely be observed. We also show that observing dust continuum emission with ALMA will help in identifying the physical processes occurring within collapsing dense cores. If the magnetic field is playing a role, the emission pattern will show evidence of a pseudo-disk and even of a magnetically driven outflow, which pure hydrodynamical calculations cannot reproduce. Conclusions. The capabilities of ALMA will enable us to make significant progress towards understanding the fragmentation at the early Class 0 stage and discovering first hydrostatic cores.

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Section: Emission Mapssupporting

confidence: 71%

Synthetic observations of first hydrostatic cores in collapsing low-mass dense cores

Commerçon¹,

Levrier²,

Maury³

et al. 2012

A&A

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“…A recent wide-field interferometer mapping in the dense molecular envelope of the ultracompact HII region W3OH, however, finds that CN is an excellent tracer of warm high density gas (Hakobian & Crutcher 2011). Maury et al (2012) show that in NGC 2264-C, an intermediatemass protocluster without significant ionizing radiation in its vicinity, the CN emission closely follows the dust continuum emission. In Fig.…”

Section: Cn Zeeman Resultsmentioning

confidence: 82%

CN Zeeman and dust polarization in a high-mass cold clump

Pillai

Kauffmann

Wiesemeyer

et al. 2016

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We report on the young massive clump (G35.20w) in W48 that previous molecular line and dust observations have revealed to be in the very early stages of star formation. Based on virial analysis, we find that a strong field of 1640 µG is required to keep the clump in pressure equilibrium. We performed a deep Zeeman effect measurement of the 113 GHz CN (1−0) line towards this clump with the IRAM 30 m telescope. We combine simultaneous fitting of all CN hyperfines with Monte Carlo simulations for a large range in realization of the magnetic field to obtain a constraint on the line-of-sight field strength of −687 ± 420 µG. We also analyze archival dust polarization observations towards G35.20w. A strong magnetic field is implied by the remarkably ordered field orientation that is perpendicular to the longest axis of the clump. Based on this, we also estimate the plane-of-sky component of the magnetic field to be ∼740 µG. This allows for a unique comparison of the two orthogonal measurements of magnetic field strength of the same region and at similar spatial scales. The expected total field strength shows no significant conflict between the observed field and that required for pressure equilibrium. By producing a probability distribution for a large range in field geometries, we show that planeof-sky projections are much closer to the true field strengths than line-of-sight projections. This can present a significant challenge for Zeeman measurements of magnetized structures, even with ALMA. We also show that CN molecule does not suffer from depletion on the observed scales in the predominantly cold and highly deuterated core in an early stage of high-mass star formation and is thus a good tracer of the dense gas.

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“…As far as we know, there are no Zeeman lines splitting observations in G202.3+2.5 (the northern part). In the NGC 2264 protocluster located half-a-degree south to the north-main region, the Zeeman lines splitting observations were studied by Maury et al (2012). However, in that region, we observe a different geometry characterising the POS magnetic field.…”

Section: Strength Of the Magnetic Field And The Effect On Filaments S...mentioning

confidence: 75%

Large-scale magnetic field in the Monoceros OB 1 east molecular cloud

Alina

Montillaud

et al. 2022

A&A

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Context. The role of large-scale magnetic fields in the evolution of star-forming regions remains elusive. Its investigation requires the observational characterization of well-constrained molecular clouds. The Monoceros OB 1 molecular cloud is a large complex containing several structures that have been shown to be engaged in an active interaction and to have a rich star formation history. However, the magnetic fields in this region have only been studied on small scales. Aims. We study the large-scale magnetic field structure and its interplay with the gas dynamics in the Monoceros OB 1 east molecular cloud. Methods. We combined observations of dust polarized emission from the Planck telescope and CO molecular line emission observations from the Taeduk Radio Astronomy Observatory 14-metre telescope. We calculated the strength of the plane-of-sky magnetic field using a modified Chandrasekhar-Fermi method and estimated the mass-over-flux ratios in different regions of the cloud. We used the comparison of the velocity and intensity gradients of the molecular line observations with the polarimetric observations to trace dynamically active regions. Results. The molecular complex shows an ordered large-scale plane-of-sky magnetic field structure. In the northern part, it is mostly orientated along the filamentary structures, while the southern part shows at least two regions with distinct magnetic field orientations. Our analysis reveals a shock region in the northern part right between two filamentary clouds that, in previous studies, were suggested to be involved in a collision. The magnetic properties of the north-main and north-eastern filaments suggest that these filaments once formed a single one, and that the magnetic field evolved together with the material and did not undergo major changes during the evolution of the cloud. In the southern part, we find that either the magnetic field guides the accretion of interstellar matter towards the cloud or it is dragged by the matter falling towards the main cloud. Conclusions. The large-scale magnetic field in the Monoceros OB 1 east molecular cloud is tightly connected to the global structure of the complex. In the northern part, it seems to serve a dynamically important role by possibly providing support against gravity in the direction perpendicular to the field and to the filament. In the southern part, it is probably the most influential factor governing the morphological structure by guiding possible gas inflow. A study of the whole Monoceros OB 1 molecular complex at large scales is necessary to form a global picture of the formation and evolution of the Monoceros OB 1 east cloud and the role of the magnetic field in this process.

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CN Zeeman observations of the NGC 2264-C protocluster

Cited by 6 publications

References 44 publications

Synthetic observations of first hydrostatic cores in collapsing low-mass dense cores

Synthetic observations of first hydrostatic cores in collapsing low-mass dense cores

CN Zeeman and dust polarization in a high-mass cold clump

Large-scale magnetic field in the Monoceros OB 1 east molecular cloud

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