Space Grant Consortium - University of Wisconsin - Green Bay

Fig. 3.— Cartoon Image of SN blastwave interacting with CSM (Stockdale, et al., 2007).
generally regarded as being evenly distributed, with a homogenously decreasing density as
the distance from the SN increases but this is not always the case, and can lead to variances
in the data (Weiler, et al., 2002). The clumps in the CSM depicted in Figure 3 are areas
of an uneven density distribution and can be the result of the stars natural loss of CSM or
because of the interaction with a binary companion star.
The CSM “fog” is different from normal fog in that long wavelength radiation is obscured
more easily, whereas the short wavelength optical radiation that is normally obscured by a
classical “fog”. Thus, the results of the radio emission generally show that over time, as the
energy of the blastwave disperses and the column density of the CSM decreases, the intensity
of the longer wavelength frequencies increase; whereas the short wavelengths then decrease
over time. The larger intensity of the longer wavelengths over time is an indication that
the radiation from the SN is not thermal, but rather synchrotron (radiation coming from
relativistic particles trapped in magnetic fields). The radiation emissions from the blastwave
are also obscured by the distant ionized hydrogen (HII) regions as seen in Figure 3. This
absorption, unlike that of the CSM, is constant with time and can easily be accounted for
in order to find the effects by the CSM alone.
Procedure
The radio data for the SNe were analyzed and processed using the computer program called
Astronomical Imaging Processing System (AIPS). The first step of the program after loading
the data onto the computer was to flag any erroneous data points that could skew the outcome
of the analysis. The erroneous data stemmed from several possible sources, such as weather
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