SIMBAD references

2014ApJ...793..126C - Astrophys. J., 793, 126 (2014/October-1)

The magnetic field of Cloud 3 in L204.


Abstract (from CDS):

The L204 dark cloud complex is a nearby filamentary structure in Ophiuchus North that has no signs of active star formation. Past studies show that L204 is interacting with the nearby runaway O star, ζ Oph, and hosts a magnetic field that is coherent across parsec-length scales. Near-infrared H-band (1.6 µm) linear polarization measurements were obtained for 3896 background stars across a 1°x1.°5 region centered on the dense Cloud 3 in L204, using the Mimir near-infrared instrument on the 1.8 m Perkins Telescope. Analysis of these observations reveals both large-scale properties and small-scale changes in the magnetic field direction in Cloud 3. In the northern and western ζ Oph facing regions of the cloud, the magnetic field appears to be pushed up against the face of the cloud. This may indicate that the UV flux from ζ Oph has compressed the magnetic field on the western edge of L204. The plane-of-sky magnetic field strength is estimated to be ∼11-26 µG using the Chandrasekhar-Fermi method. The polarimetry data also reveal that the polarization efficiency (PE ≡ PH/AV) steadily decreases with distance from ζ Oph (-0.09%±0.03%/mag/pc). Additionally, power-law fits of PE versus AV for localized samples of probe stars show steeper negative indices with distance from ζ Oph. Both findings highlight the importance of external illumination, here from ζ Oph, in aligning dust grains to embedded magnetic fields.

Abstract Copyright:

Journal keyword(s): dust, extinction - ISM: clouds - ISM: individual: L204 - ISM: magnetic fields - magnetic fields - polarization

VizieR on-line data: <Available at CDS (J/ApJ/793/126): table1.dat>

Status at CDS : All or part of tables of objects will not be ingested in SIMBAD.

Simbad objects: 6

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