The Correlation Between Hydrogen Column Density and Dispersion Measure Using Pulsars

Nicholas Nelson and Nathan Theis, “The Correlation Between Hydrogen Column Density and Dispersion Measure Using Pulsars” 

Mentor: David Kaplan, Physics, Letters & Science (College of) 

Poster #132 

Pulsars emit beams of electromagnetic radiation from their poles across the electromagnetic spectrum.  By analyzing pulsar radio wave and x-ray emissions we can determine a correlation between the Dispersion Measure (DM) and the Hydrogen Column Density (N_\mathrm{H}).  This correlation allows us to better understand physical connections between different phases of the Interstellar Medium.  We collect spectral analysis of 88 pulsars to find a best fit linear relationship of N_\mathrm{H} N_\mathrm{H}\ \left({10}^{20}{\mathrm{cm}}^{-2}\right)=0.28\pm0.05\ \mathrm{DM}\ \mathrm{c\ }{\mathrm{cm}}^-3.  This builds upon the work conducted by He et al. (2013) by increasing the number of pulsars sampled and updating the DM-N_\mathrm{H} correlation with more current spectral analysis.