Distortion of Magnetic Fields in Barnard 335

Fuente: arXiv
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Main Authors: Kandori, Ryo, Saito, Masao, Tamura, Motohide, Tomisaka, Kohji, Matsumoto, Tomoaki, Tazaki, Ryo, Nagata, Tetsuya, Kusakabe, Nobuhiko, Nakajima, Yasushi, Kwon, Jungmi, Nagayama, Takahiro, Tatematsu, Ken'ichi
Format: Preprint
Published: 2020
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author Kandori, Ryo
Saito, Masao
Tamura, Motohide
Tomisaka, Kohji
Matsumoto, Tomoaki
Tazaki, Ryo
Nagata, Tetsuya
Kusakabe, Nobuhiko
Nakajima, Yasushi
Kwon, Jungmi
Nagayama, Takahiro
Tatematsu, Ken'ichi
author_facet Kandori, Ryo
Saito, Masao
Tamura, Motohide
Tomisaka, Kohji
Matsumoto, Tomoaki
Tazaki, Ryo
Nagata, Tetsuya
Kusakabe, Nobuhiko
Nakajima, Yasushi
Kwon, Jungmi
Nagayama, Takahiro
Tatematsu, Ken'ichi
contents In this study, the detailed magnetic field structure of the dense protostellar core Barnard 335 (B335) was revealed based on near-infrared polarimetric observations of background stars to measure dichroically polarized light produced by magnetically aligned dust grains in the core. Magnetic fields pervading B335 were mapped using 24 stars after subtracting unrelated ambient polarization components, for the first time revealing that they have an axisymmetrically distorted hourglass-shaped structure toward the protostellar core. On the basis of simple two- and three-dimensional magnetic field modeling, magnetic inclination angles in the plane-of-sky and line-of-sight directions were determined to be $90^{\circ} \pm 7^{\circ}$ and $50^{\circ} \pm 10^{\circ}$, respectively. The total magnetic field strength of B335 was determined to be $30.2 \pm 17.7$ $μ{\rm G}$. The critical mass of B335, evaluated using both magnetic and thermal/turbulent support against collapse, was determined to be $M_{\rm cr} = 3.37 \pm 0.94$ ${\rm M}_{\odot}$, which is identical to the observed core mass of $M_{\rm core}=3.67$ M$_{\odot}$. We thus concluded that B335 started its contraction from a condition near equilibrium. We found a linear relationship in the polarization versus extinction diagram, up to $A_V \sim 15$ mag toward the stars with the greatest obscuration, which verified that our observations and analysis provide an accurate depiction of the core.
format Preprint
id arxiv_https___arxiv_org_abs_2001_08542
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle Distortion of Magnetic Fields in Barnard 335
Kandori, Ryo
Saito, Masao
Tamura, Motohide
Tomisaka, Kohji
Matsumoto, Tomoaki
Tazaki, Ryo
Nagata, Tetsuya
Kusakabe, Nobuhiko
Nakajima, Yasushi
Kwon, Jungmi
Nagayama, Takahiro
Tatematsu, Ken'ichi
Astrophysics of Galaxies
In this study, the detailed magnetic field structure of the dense protostellar core Barnard 335 (B335) was revealed based on near-infrared polarimetric observations of background stars to measure dichroically polarized light produced by magnetically aligned dust grains in the core. Magnetic fields pervading B335 were mapped using 24 stars after subtracting unrelated ambient polarization components, for the first time revealing that they have an axisymmetrically distorted hourglass-shaped structure toward the protostellar core. On the basis of simple two- and three-dimensional magnetic field modeling, magnetic inclination angles in the plane-of-sky and line-of-sight directions were determined to be $90^{\circ} \pm 7^{\circ}$ and $50^{\circ} \pm 10^{\circ}$, respectively. The total magnetic field strength of B335 was determined to be $30.2 \pm 17.7$ $μ{\rm G}$. The critical mass of B335, evaluated using both magnetic and thermal/turbulent support against collapse, was determined to be $M_{\rm cr} = 3.37 \pm 0.94$ ${\rm M}_{\odot}$, which is identical to the observed core mass of $M_{\rm core}=3.67$ M$_{\odot}$. We thus concluded that B335 started its contraction from a condition near equilibrium. We found a linear relationship in the polarization versus extinction diagram, up to $A_V \sim 15$ mag toward the stars with the greatest obscuration, which verified that our observations and analysis provide an accurate depiction of the core.
title Distortion of Magnetic Fields in Barnard 335
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2001.08542