Semester

Spring

Date of Graduation

2014

Document Type

Thesis

Degree Type

MS

College

Eberly College of Arts and Sciences

Department

Physics and Astronomy

Committee Chair

Loren Anderson

Committee Co-Chair

Duncan Lorimer

Committee Member

DJ Pisano.

Abstract

HII regions are clouds of ionized hydrogen gas surrounding B0- and O-type stars. The ionized hydrogen in these regions emits both radio recombination line (RRL) and also thermal radio continuum. Diffuse ionized hydrogen, known as the 'Warm Ionized Medium' (WIM) also exists in the Galaxy. The WIM also emits RRLs and thermal radio continuum. Previous observation of compact \hii regions found two RRL components for many sources, one from the \hii region and the others from the WIM. By observing off-target positions sampling only the diffuse emission, we discerned the correct source velocities for 93 out of 116 HII regions that have multiple RRL components. We assigned kinematic distances to these sources by analyzing hydrogen absorption spectra taken toward the sources. We found that 64% of our sources lie beyond the tangent point distance.

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