Magnetic Fields in the Pillars of Creation

TL;DR

This study maps magnetic fields in the Pillars of Creation using dust polarization data, revealing how magnetic field strength influences star formation processes and supports a model of initial weak fields strengthening over time.

Contribution

It provides the first detailed magnetic field maps of the Pillars of Creation region derived from SOFIA/HAWC+ data, and analyzes their role in star formation.

Findings

Magnetic field strengths range from 50-130 microGauss.

Star formation occurs where magnetic fields are weak enough to allow collapse.

Magnetic fields are dynamically important and likely strengthened through realignment and compression.

Abstract

Due to dust grain alignment with magnetic fields, dust polarization observations of far-infrared emission from cold molecular clouds are often used to trace magnetic fields, allowing a probe of the effects of magnetic fields on the star formation process. We present inferred magnetic field maps of the Pillars of Creation region within the larger M16 emission nebula, derived from dust polarization data in the 89 and 154 micron continuum using SOFIA/HAWC+. We derive magnetic field strength estimates using the Davis-Chandrasekhar-Fermi method. We compare the polarization and magnetic field strengths to column densities and dust continuum intensities across the region to build a coherent picture of the relationship between star forming activity and magnetic fields in the region. The projected magnetic field strengths derived are in the range of 50-130 microGauss, which is typical for clouds of similar n(H2), i.e., molecular hydrogen volume density on the order of 10^4-10^5 cm^(-3). We conclude that star formation occurs in the finger tips when the magnetic fields are too weak to prevent radial collapse due to gravity but strong enough to oppose OB stellar radiation pressure, while in the base of the fingers the magnetic fields hinder mass accretion and consequently star formation. We also support an initial weak field model (<50 microGauss) with subsequent strengthening through realignment and compression, resulting in a dynamically important magnetic field.