HartRAO
PO Box 443
Krugersdorp 1740
South Africa
Tel: 012 301 3224
Int. Code: +27 12
[email protected]
http://www.hartrao.ac.za
Squiggly Lines Worksheet
Squiggly lines, or formally astronomical spectroscopy, represent the practical
application of quantum mechanics. Microwave Amplification of Stimulated Emitted
Radiation (MASER) in effect are negative absorption lines with very high brightness
temperatures. These masers are excellent signposts of massive star-forming regions.
Also they are excellent diagnostic tools for the study of dynamical phenomena and
magnetic fields. Magnetic field strengths towards massive star forming regions can
be determined by measuring the velocity difference between left-handed (LCP) &
right-handed (RCP) circular polarization maser components. This velocity separation
is caused by Zeeman splitting of the hyperfine quantum levels.
In this simplified study you are to:
1. Process the raw data of previously observed spectra
a. What is the source we are looking at?
b. How many observations were taken?
c. At what frequency were observations taken?
d. Describe the process followed
i. What programme was used?
ii. What script was used and describe what it does?
e. Was there any spurious noise in the spectra?
f. What does the baseline look like? Flat and at 0 or rippled?
2. Fit Gaussian models to the spectra
a. Record the VELOCITY PEAK, VELOCITY WIDTH, and FLUX
STRENGTH for both RCP and LCP
3. Determine the magnetic field strength using the equation
𝐵(𝑚𝐺) =
(𝑣(𝑅𝐶𝑃) − 𝑣(𝐿𝐶𝑃)
,
𝜆𝑔
λg(6031) = 0.079,
λg(6035) = 0.056
4. Write conclusions
a. Is your baseline flat or rippled?
b. Did you get a good Gaussian fit to each maser component?
c. What were the results of your magnetic field measurements?
d. For the two components were the values of B, and their sign, the
same?
e. What does it mean if they are different?
f. Any other observations?