Distortion of Magnetic Fields in a Starless Core II: 3D Magnetic Field Structure of FeSt 1-457

Kandori, Ryo; Tamura, Motohide; Tomisaka, Kohji; Kusakabe, Nobuhiko; Kwon, Jungmi; Nagayama, Takahiro; Nagata, T.; Tatematsu, Ken’ichi

doi:10.3847/1538-4357/aa8d18

Cited by 19 publications

(18 citation statements)

References 29 publications

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“…Overall, the assumptions of β 1 at the transonic radius and µ 1 within the core are mutually consistent. Furthermore, the average interior value of β ≡ δθ = 0.12 Kandori et al (2017) for the starless core Fest 1-457 lies within the range of estimated values of β inside the transonic radius of H-MM1 (see Figure 7).…”

Section: Radius (Pc)supporting

confidence: 70%

Magnetic Field Structure of Dense Cores Using Spectroscopic Methods

Auddy

Myers²,

Basu³

et al. 2019

ApJ

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We develop a new "core field structure" (CFS) model to predict the magnetic field strength and magnetic field fluctuation profile of dense cores using gas kinematics. We use spatially resolved observations of the nonthermal velocity dispersion from the Green Bank Ammonia survey along with column density maps from SCUBA-2 to estimate the magnetic field strength across seven dense cores located in the L1688 region of Ophiuchus. The CFS model predicts the profile of the relative field fluctuation, which is related to the observable dispersion in direction of the polarization vectors. Within the context of our model we find that all the cores have a transcritical mass-to-flux ratio.

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Section: Radius (Pc)supporting

confidence: 70%

Magnetic Field Structure of Dense Cores Using Spectroscopic Methods

Auddy

Myers²,

Basu³

et al. 2019

ApJ

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“…For 3D magnetic field modeling, we follow the procedure described in a previous paper (Kandori et al 2017b, hereafter Paper II, see also, Kandori et al 2019, hereafter Paper VI). The 3D version of the simple parabolic function employed in Paper I, z(r, ϕ, g) = g + gCr 2 in cylindrical coordinates (r, z, ϕ), is used to model the core magnetic fields, where g specifies the magnetic field line, C is the curvature of the lines, and ϕ is the azimuth angle (measured in the plane perpendicular to the r).…”

Section: D Magnetic Fieldmentioning

confidence: 99%

Distortion of magnetic fields in Barnard 68

Kandori

Tamura

Saito

et al. 2019

Publications of the Astronomical Society of Japan

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The magnetic field structure, kinematical stability, and evolutionary status of the starless dense core Barnard 68 (B68) are revealed based on the near-infrared polarimetric observations of background stars, measuring the dichroically polarized light produced by aligned dust grains in the core. After subtracting unrelated ambient polarization components, the magnetic fields pervading B68 are mapped using 38 stars and axisymmetrically distorted hourglass-like magnetic fields are obtained, although the evidence for the hourglass field is not very strong. On the basis of simple 2D and 3D magnetic field modeling, the magnetic inclination angles on the plane-ofsky and in the line-of-sight direction are determined to be 47 • ± 5 • and 20 • ± 10 • , respectively. The total magnetic field strength of B68 is obtained to be 26.1 ± 8.7 µG. The critical mass of B68, evaluated using both magnetic and thermal/turbulent support, is M cr = 2.30 ± 0.20 M ⊙ , which is consistent with the observed core mass of M core = 2.1 M ⊙ , suggesting nearly critical state. We found a relatively linear relationship between polarization and extinction up to A V ∼ 30 mag toward the stars with deepest obscuration. Further theoretical and observational studies are required to explain the dust alignment in cold and dense regions in the core.

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“…If the line-of-sight magnetic inclination angle (γ mag ) is known, the total magnetic field strength can be obtained, allowing the magnetic criticality and kinematical stability of each core to be evaluated precisely. If a dense core is associated with hourglass-shaped magnetic fields, specific polarization patterns can appear because of the depolarization effect of the inclined distorted magnetic field structure, and γ mag can be estimated through a simple model fitting (Kandori et al 2017b, hereafter Paper II; see also Kataoka et al 2012;Kandori et al 2020a, Paper VI). To date, four dense cores with hourglass-shaped magnetic field structures have been identified (FeSt 1-457: Paper I, Barnard 68: Kandori et al 2019, Barnard 335: Kandori et al 2020c in Pipe Nebula: Kandori et al 2020b).…”

Section: Introductionmentioning

confidence: 99%

Distortion of Magnetic Fields in BHR 71

Kandori

Tamura

Saito

et al. 2020

ApJ

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The magnetic field structure of a star-forming Bok globule BHR 71 was determined based on near-infrared polarimetric observations of background stars. The magnetic field in BHR 71 was mapped from 25 stars. By using a simple 2D parabolic function, the plane-of-sky magnetic axis of the core was found to be θ mag = 125 • ± 11 • . The plane-of-sky mean magnetic field strength of BHR 71 was found to be B pos = 8.8 − 15.0 µG, indicating that the BHR 71 core is magnetically supercritical with λ = 1.44 − 2.43. Taking into account the effect of thermal/turbulent pressure and the plane-of-sky magnetic field component, the critical mass of BHR 71 was M cr = 14.5 − 18.7 M ⊙ , which is consistent with the observed core mass of M core ≈ 14.7 M ⊙ (Yang et al. 2017). We conclude that BHR 71 is in a condition close to a kinematically critical state, and the magnetic field direction lies close to the plane of sky. Since BHR 71 is a star-forming core, a significantly subcritical condition (i.e., the magnetic field direction deviating from the plane of sky) is unlikely, and collapsed from a condition close to a kinematically critical state. There are two possible scenarios to explain the curved magnetic fields of BHR 71, one is an hourglass-like field structure due to mass accumulation and the other is the Inoue & Fukui (2013) mechanism, which proposes the interaction of the core with a shock wave to create curved magnetic fields wrapping around the core.

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Distortion of Magnetic Fields in a Starless Core II: 3D Magnetic Field Structure of FeSt 1-457

Cited by 19 publications

References 29 publications

Magnetic Field Structure of Dense Cores Using Spectroscopic Methods

Magnetic Field Structure of Dense Cores Using Spectroscopic Methods

Distortion of magnetic fields in Barnard 68

Distortion of Magnetic Fields in BHR 71

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