Magnetic Field Uniformity Across the GF 9-2 YSO, L1082C Dense Core, and GF 9 Filamentary Dark Cloud

TL;DR

This study reveals a remarkably uniform magnetic field across the GF 9 cloud, from its periphery to the dense core containing a young stellar object, challenging weak-field formation models.

Contribution

It combines multi-wavelength polarimetry data to demonstrate the continuity and uniformity of the magnetic field across different scales in GF 9.

Findings

Magnetic field remains uniform from cloud edge to YSO environment.

No significant change in B-field orientation with offset or wavelength.

Distance to GF 9 determined as 270 +/- 10 pc.

Abstract

The orientation of the magnetic field (B-field) in the filamentary dark cloud GF 9 was traced from the periphery of the cloud into the L1082C dense core that contains the low-mass, low-luminosity Class 0 young stellar object (YSO) GF 9-2 (IRAS 20503+6006). This was done using SOFIA HAWC+ dust thermal emission polarimetry (TEP) at 216 um in combination with Mimir near-infrared background starlight polarimetry (BSP) conducted at H-band (1.6 um) and K-band (2.2 um). These observations were augmented with published I-band (0.77 um) BSP and Planck 850 um TEP to probe B-field orientations with offset from the YSO in a range spanning 6000 AU to 3 pc. No strong B-field orientation change with offset was found, indicating remarkable uniformity of the B-field from the cloud edge to the YSO environs. This finding disagrees with weak-field models of cloud core and YSO formation. The continuity of inferred B-field orientations for both TEP and BSP probes is strong evidence that both are sampling a common B-field that uniformly threads the cloud, core, and YSO region. Bayesian analysis of Gaia DR2 stars matched to the Mimir BSP stars finds a distance to GF 9 of 270 +/- 10 pc. No strong wavelength dependence of B-field orientation angle was found, contrary to previous claims.