Detection of Linearly Polarized 6.9 mm Continuum Emission from the Class 0 Young Stellar Object NGC1333 IRAS4A

TL;DR

This study presents high-resolution JVLA observations of polarized 6.9 mm emission from the Class 0 YSO NGC1333 IRAS4A, revealing magnetic field structures and differences from previous shorter wavelength observations, indicating probing of different regions.

Contribution

First high-resolution 6.9 mm polarization observations of a Class 0 YSO, comparing magnetic field structures with submillimeter data to understand dust and magnetic field evolution.

Findings

Detected polarized emission at 6.9 mm from NGC1333 IRAS4A.

Observed slight deviations in polarization angles compared to 0.88 mm data.

Lower optical depth at 6.9 mm suggests probing inner regions of the core.

Abstract

We report new Karl G. Jansky Very Large Array (JVLA), 0$"$.5 angular resolution observations of linearly polarized continuum emission at 6.9 mm, towards the Class 0 young stellar object (YSO) NGC1333 IRAS4A. This target source is a collapsing dense molecular core, which was resolved at short wavelengths to have hourglass shaped B-field configuration. We compare these 6.9 mm observations with previous polarization Submillimeter Array (SMA) observations at 0.88 mm, which have comparable angular resolution ($\sim$0$"$7). We found that at the same resolution, the observed polarization position angles at 6.9 mm are slightly deviated from those observed at 0.88 mm. Due to the lower optical depth of the emission at 6.9 mm, and the potential effect of dust grain growth, the new JVLA observations are likely probing B-field alignments in regions interior to those sampled by the previous polarization observations at higher frequencies. Our understanding can be improved by more sensitive observations, and observations for the more extended spatial scales.