# First Sub-pc Sale Mapping of Magnetic Fields in the Vicinity of a Very Low Luminosity Object, L1521F-IRS

## TL;DR

This study maps magnetic fields at sub-parsec scales around the VeLLO L1521F-IRS using high-sensitivity submm polarization data, revealing strong, ordered magnetic fields that dominate the core's energy budget and influence its evolution.

## Contribution

First high-resolution submm polarization observations of a VeLLO core, demonstrating the importance of magnetic fields in its structure and dynamics.

## Key findings

- Magnetic fields are well ordered and connected across scales.
- Magnetic energy exceeds kinetic energy, indicating magnetic dominance.
- Core is magnetically supercritical with a mass-to-flux ratio of 2.3.

## Abstract

L1521F is found to be forming multiple cores and it is cited as an example of the densest core with an embedded VeLLO in a highly dynamical environment. We present the core-scale magnetic fields (B-fields) in the near vicinity of the VeLLO L1521F-IRS using submm polarization measurements at 850$~\mu$m using JCMT POL-2. This is the first attempt to use high-sensitivity observations to map the sub-parsec scale B-fields in a core with a VeLLO. The B-fields are ordered and very well connected to the parsec-scale field geometry seen in our earlier optical polarization observations and the large-scale structure seen in Planck dust polarization. The core scale B-field strength estimated using Davis-Chandrasekhar-Fermi relation is $\rm 330\pm100~\mu$G which is more than ten times of the value we obtained in the envelope (envelope in this paper is "core envelope"). This indicates that B-fields are getting stronger on smaller scales. The magnetic energies are found to be 1 to 2 orders of magnitude higher than non-thermal kinetic energies in the envelope and core. This suggests that magnetic fields are more important than turbulence in the energy budget of L1521F. The mass-to-flux ratio of 2.3$\pm$0.7 suggests that the core is magnetically-supercritical. The degree of polarization is steadily decreasing towards the denser part of the core with a power law slope of -0.86.