Graduation Year


Document Type

Open Access Senior Thesis

Degree Name

Bachelor of Science


Physics & Astronomy

Reader 1

Philip Choi

Terms of Use & License Information

Terms of Use for work posted in Scholarship@Claremont.

Rights Information

© 2008 Erica Nelson


Two-dimensional information on the kinematics and spatial distribution of gas in spiral galaxies is encoded in radio observations of their one-dimensional 21-cm neutral hydrogen (HI) line profiles. More than ten thousand HI profiles have been published and are publicly available. In order to explore the parameter space mapped out by the 21-cm neutral hydrogen line pro file, we have modified and run a FORTRAN-based computer simulation code. We have identified 7 control parameters that define the morphology of the modelled galaxy: they describe the neutral hydrogen gas distribution (density and spatial location of the gas), characteristics of its rotation curve, warps, asymmetries, and finally, the viewing angle. All except the last of these parameters tell us significant physical information about the galaxy but a determination of them is not immediately apparent from the two-dimensional 21-cm line profile. Hence, the goal of this exploration is to find meaningful correlations between the observed 21-cm line profile features and the underlying physical parameters.


Previously linked to as:,46

OCLC number: 549439183