Princeton University Library Catalog
- Masters, Zoe [Browse]
- Senior thesis
- Page, Lyman [Browse]
- Meyers, Peter [Browse]
- Princeton University. Department of Physics [Browse]
- Class year:
- 71 pages
- Restrictions note:
- Walk-in Access. This thesis can only be viewed on computer terminals at the Mudd Manuscript Library.
- Summary note:
- We study the cosmic microwave background (CMB) because its anisotropies
contain information about the birth, contents, and evolution of the universe.
In order to extract information from the CMB, we need accurate models of
the galactic foreground. The four known components of the galactic foreground
are synchrotron radiation, thermal dust, spinning dust, and free-free
emission. Free-free emission is known to be correlated with H\(\alpha\) radiation
because both processes occur in regions of ionized hydrogen gas called the
Warm Ionized Medium (WIM) and are directly correlated with the density of
these regions. The scaling of free-free emission with H\(\alpha\) radiation depends on
the temperature of the WIM. In this paper we investigate the physical basis
for the scaling law between free-free emission and H\(\alpha\) radiation. We use this
scaling law as a lens to examine existing estimates of free-free emission and
to determine what these data suggest about the temperature of the WIM.
We find that for approximately 80 percent of the sky, where extinction from
dust is minimal (t < 1), H\(\alpha\) radiation and free-free emission follow the theoretically
expected scaling law for temperatures that are within the known
range of WIM temperatures.