OH Zeeman measurement of the magnetic field in the L1544 core

Richard M. Crutcher; Thomas H. Troland

doi:10.1086/312770

OH Zeeman measurement of the magnetic field in the L1544 core

Richard M. Crutcher, Thomas H. Troland

Physics And Astronomy

Research output: Contribution to journal › Article › peer-review

58 Scopus citations

Abstract

We report observations with the Arecibo telescope of the Zeeman effect in the 1665 and 1667 MHz lines of OH toward eight dark cloud cores. For L1544, the inferred line-of-sight magnetic field is B_LOS = +11 ∓ 2 μG. The L1544 starless core has been observed to have infall motions; it may be very close to forming a star. B_LOS ≈ 11 μG is consistent with the prediction of an ambipolar diffusion model computed specifically for this core before the Zeeman measurements were made; however, in order to obtain agreement with the data this model has B inclined by only 16° to the plane of the sky. Virial arguments show that unless the magnetic field is mainly in the plane of the sky, it is not important for support of the L1544 core. For L1457S our result is B_LOS = -24 ± 7 μG, a possible but not definite detection. The other six cores were observed only with short integration times, and the Zeeman effect was not detected in these cores.

Original language	English
Pages (from-to)	L139-L142
Journal	Astrophysical Journal
Volume	537
Issue number	2 PART 2
DOIs	https://doi.org/10.1086/312770
State	Published - Jul 10 2000

Bibliographical note

Funding Information:
This work was partially supported by NSF grants AST 96-13999, AST 98-20641, and AST 99-88341. The Arecibo Observatory is part of the National Astronomy and Ionosphere Center, which is operated by Cornell University under a co-operative agreement with the National Science Foundation.

Keywords

ISM: individual (L1544)
ISM: magnetic fields
ISM: molecules
Polarization
Stars: formation

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1086/312770

Cite this

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title = "OH Zeeman measurement of the magnetic field in the L1544 core",

abstract = "We report observations with the Arecibo telescope of the Zeeman effect in the 1665 and 1667 MHz lines of OH toward eight dark cloud cores. For L1544, the inferred line-of-sight magnetic field is BLOS = +11 ∓ 2 μG. The L1544 starless core has been observed to have infall motions; it may be very close to forming a star. BLOS ≈ 11 μG is consistent with the prediction of an ambipolar diffusion model computed specifically for this core before the Zeeman measurements were made; however, in order to obtain agreement with the data this model has B inclined by only 16° to the plane of the sky. Virial arguments show that unless the magnetic field is mainly in the plane of the sky, it is not important for support of the L1544 core. For L1457S our result is BLOS = -24 ± 7 μG, a possible but not definite detection. The other six cores were observed only with short integration times, and the Zeeman effect was not detected in these cores.",

keywords = "ISM: individual (L1544), ISM: magnetic fields, ISM: molecules, Polarization, Stars: formation",

author = "Crutcher, {Richard M.} and Troland, {Thomas H.}",

note = "Funding Information: This work was partially supported by NSF grants AST 96-13999, AST 98-20641, and AST 99-88341. The Arecibo Observatory is part of the National Astronomy and Ionosphere Center, which is operated by Cornell University under a co-operative agreement with the National Science Foundation.",

year = "2000",

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doi = "10.1086/312770",

language = "English",

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T1 - OH Zeeman measurement of the magnetic field in the L1544 core

AU - Crutcher, Richard M.

AU - Troland, Thomas H.

N1 - Funding Information: This work was partially supported by NSF grants AST 96-13999, AST 98-20641, and AST 99-88341. The Arecibo Observatory is part of the National Astronomy and Ionosphere Center, which is operated by Cornell University under a co-operative agreement with the National Science Foundation.

PY - 2000/7/10

Y1 - 2000/7/10

N2 - We report observations with the Arecibo telescope of the Zeeman effect in the 1665 and 1667 MHz lines of OH toward eight dark cloud cores. For L1544, the inferred line-of-sight magnetic field is BLOS = +11 ∓ 2 μG. The L1544 starless core has been observed to have infall motions; it may be very close to forming a star. BLOS ≈ 11 μG is consistent with the prediction of an ambipolar diffusion model computed specifically for this core before the Zeeman measurements were made; however, in order to obtain agreement with the data this model has B inclined by only 16° to the plane of the sky. Virial arguments show that unless the magnetic field is mainly in the plane of the sky, it is not important for support of the L1544 core. For L1457S our result is BLOS = -24 ± 7 μG, a possible but not definite detection. The other six cores were observed only with short integration times, and the Zeeman effect was not detected in these cores.

AB - We report observations with the Arecibo telescope of the Zeeman effect in the 1665 and 1667 MHz lines of OH toward eight dark cloud cores. For L1544, the inferred line-of-sight magnetic field is BLOS = +11 ∓ 2 μG. The L1544 starless core has been observed to have infall motions; it may be very close to forming a star. BLOS ≈ 11 μG is consistent with the prediction of an ambipolar diffusion model computed specifically for this core before the Zeeman measurements were made; however, in order to obtain agreement with the data this model has B inclined by only 16° to the plane of the sky. Virial arguments show that unless the magnetic field is mainly in the plane of the sky, it is not important for support of the L1544 core. For L1457S our result is BLOS = -24 ± 7 μG, a possible but not definite detection. The other six cores were observed only with short integration times, and the Zeeman effect was not detected in these cores.

KW - ISM: individual (L1544)

KW - ISM: magnetic fields

KW - ISM: molecules

KW - Polarization

KW - Stars: formation

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SP - L139-L142

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2 PART 2

ER -

OH Zeeman measurement of the magnetic field in the L1544 core

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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