MULTI-SCALE ANALYSIS OF MAGNETIC FIELDS IN FILAMENTARY MOLECULAR CLOUDS IN ORION A

Journal Article · Thu Nov 10 04:00:00 EST 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/741/2/112; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21612667

Poidevin, Frederick ^[1]; Bastien, P ^[2]

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1. Department of Physics and Astronomy, UCL, Gower Street, London WC1E 6BT (United Kingdom)
2. Departement de Physique and Observatoire du Mont-Megantic, Universite de Montreal, C.P. 6128, Succ. Centre-Ville, Montreal, Quebec H3C 3J7 (Canada)

New visible and K-band polarization measurements of stars surrounding molecular clouds in Orion A and stars in the Becklin-Neugebauer (BN) vicinity are presented. Our results confirm that magnetic fields located inside the Orion A molecular clouds and in their close neighborhood are spatially connected. On and around the BN object, we measured the angular offsets between the K-band polarization data and available submillimeter (submm) data. We find high values of the polarization degree, P{sub K} , and of the optical depth, {tau}{sub K}, close to an angular offset position of 90 Degree-Sign whereas lower values of P{sub K} and {tau}{sub K} are observed for smaller angular offsets. We interpret these results as evidence for the presence of various magnetic field components toward lines of sight in the vicinity of BN. On a larger scale, we measured the distribution of angular offsets between available H-band polarization data and the same submm data set. Here we find an increase of (P{sub H}) with angular offset, which we interpret as a rotation of the magnetic field by {approx}< 60 Degree-Sign . This trend generalizes previous results on small scales toward and around lines of sight to BN and is consistent with a twist of the magnetic field on a larger scale toward OMC-1. A comparison of our results with several other studies suggests that a two-component magnetic field, perhaps helical, could be wrapping the OMC-1 filament.

• OSTI ID: 21612667
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 741; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
DISTRIBUTION
MAGNETIC FIELDS
MOTION
POLARIZATION
ROTATION
STARS