Issue |
A&A
Volume 441, Number 3, October III 2005
|
|
---|---|---|
Page(s) | 1217 - 1228 | |
Section | Astronomical instrumentation | |
DOI | https://doi.org/10.1051/0004-6361:20052990 | |
Published online | 23 September 2005 |
Faraday rotation measure synthesis
1
Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen, The Netherlands e-mail: m.a.brentjens@astro.rug.nl
2
ASTRON, PO Box 2, 7990 AA Dwingeloo, The Netherlands
Received:
4
March
2005
Accepted:
20
June
2005
We extend the rotation measure work of Burn (1966, MNRAS, 133, 67) to
the cases of limited sampling of space and non-constant
emission spectra. We introduce the rotation measure transfer function
(RMTF), which is an excellent predictor of
ambiguity problems
with the
coverage. Rotation measure synthesis can be
implemented very efficiently on modern computers. Because the analysis
is easily applied to wide fields, one can conduct very fast RM surveys
of weak spatially extended sources. Difficult situations, for example
multiple sources along the line of sight, are easily detected and
transparently handled. Under certain conditions, it is even possible
to recover the emission as a function of Faraday depth within a single
cloud of ionized gas. Rotation measure synthesis has already been
successful in discovering widespread, weak, polarized emission
associated with the Perseus cluster (de Bruyn & Brentjens 2005, A&A, 441, 931). In
simple, high signal to noise situations it is as good as traditional
linear fits to χ versus
plots. However, when the
situation is more complex or very weak polarized emission at high
rotation measures is expected, it is the only viable option.
Key words: methods: data analysis / techniques: polarimetric / magnetic fields / polarization / ISM: magnetic fields / Cosmology: large-scale structure of Universe
© ESO, 2005
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