Date Thesis Awarded

5-2024

Access Type

Honors Thesis -- Access Restricted On-Campus Only

Degree Name

Bachelors of Science (BS)

Department

Physics

Advisor

Irina Novikova

Committee Members

Allison Costa

Iaci Ross

Abstract

We utilized the Karl G. Jansky Very Large Array radio interferometer to make polarization measurements of eight distant galaxies viewed through and near the IC 1396 nebula at frequencies between 4.43 GHz and 7.31 GHz. These return Faraday rotation measurements that we use as probes to assess the extent to which the Galactic magnetic field is modified by the HII region. We find that sources having lines of sight passing through IC 1396 have an excess rotation measure (RM) values of 62-465 rad m-2 with respect to the background RM. We employed two separate techniques to determine the RM of each source, a least-squares fit to χ(λ2) and Rotation Measure Synthesis. We additionally applied a simplified shell model to understand the plasma structure of IC 1396, which returned the geometry of the shell, electron densities as well as expected RM values. We find the observed RMs are smaller than those predicted by the model, while aligning with the values returned by RM Synthesis. We also find sources with lines of sight passing through and near IC 1396 are consistent with the polarity with the Galactic background RM. Additionally, these results indicate that the Galactic magnetic field is not amplified by the dynamics, such as ionization fronts, of the nebula.

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