Multi-scale Analysis of Magnetic Fields in Filamentary Molecular Clouds in Orion A

Poidevin, F.; Bastien, P.; Jones, T. J.
Referencia bibliográfica

The Astrophysical Journal, Volume 741, Issue 2, article id. 112, 17 pp. (2011).

Fecha de publicación:
11
2011
Número de autores
3
Número de autores del IAC
0
Número de citas
16
Número de citas referidas
13
Descripción
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, PK , and of the optical depth, τ K , close to an angular offset position of 90° whereas lower values of PK and τ 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 langPH rang with angular offset, which we interpret as a rotation of the magnetic field by <~ 60°. 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.