Near-Infrared Imaging Polarimetry of the Serpens Cloud Core: Magnetic Field Structure, Outflows, and Inflows in A Cluster Forming Clump

TL;DR

This study uses near-infrared polarimetry to reveal the magnetic field structure, outflows, and inflows in the Serpens cloud core, providing insights into the role of magnetic fields in star formation within a cluster-forming environment.

Contribution

It presents the first detailed magnetic field mapping in the Serpens core, showing an hourglass shape and estimating its strength, highlighting magnetic influence on cloud dynamics and star formation.

Findings

Magnetic field has an hourglass shape aligned nearly perpendicular to cloud elongation.

Estimated magnetic field strength is approximately 100 microGauss.

Magnetic, outflow, and gravitational forces collectively influence cloud dynamics.

Abstract

We made deep NIR imaging polarimetry toward the Serpens cloud core. The polarization vector maps enable us to newly detect 24 small IR reflection nebulae with YSOs. Polarization measurements of NIR point sources indicate an hourglass-shaped magnetic field, of which symmetry axis is nearly perpendicular to the elongation of the C18O (J=1-0) or submillimeter continuum emission. The bright part of C18O (J=1-0), submillimeter continuum cores as well as many class 0/I objects are located just toward the constriction region of the hourglass-shaped magnetic field. Applying the CF method, the magnetic field strength was estimated to be ~100 muG, suggesting that the ambient region of the Serpens cloud core is moderately magnetically supercritical. These suggest that the Serpens cloud core first contracted along the magnetic field to be an elongated cloud, which is perpendicular to the magnetic field, and that then the central part contracted cross the magnetic field due to the high density in the central region of the cloud core, where star formation is actively continuing. Comparison of this magnetic field with the previous observations of molecular gas and large-scale outflows suggests a possibility that the cloud dynamics is controlled by the magnetic field, protostellar outflows and gravitational inflows. This appears to be in good agreement with the outflow-driven turbulence model and implies the importance of the magnetic field to continuous star formation in the center region of the cluster forming region.