Issue |
Astron. Astrophys. Suppl. Ser.
Volume 132, Number 2, October II 1998
|
|
---|---|---|
Page(s) | 261 - 273 | |
DOI | https://doi.org/10.1051/aas:1998446 | |
Published online | 15 October 1998 |
Spectral distributions in compact radio sources
I. Imaging with VLBI data
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany
Send offprint request to: A.P. Lobanov
Received:
11
September
1997
Accepted:
4
April
1998
We discuss a technique for mapping the synchrotron turnover
frequency distribution using nearly simultaneous, multi–frequency
VLBI observations. The limitations of the technique arising from limited
spatial sampl ing and frequency coverage are investigated. The
errors caused by uneven spatial sampl ing of typical
multi–frequency VLBA datasets are estimated through numerical
simulations, and are shown to be of the order of 10%, for pixels
with the deconvolution . The fitted spectral
parameters are corrected for the errors due to limited frequency
coverage of VLBI data. First results from mapping the turnover frequency
distribution in 3C 345 are presented.
Key words: methods: data analysis / methods: observational / quasars: individual: 3C 345 / techniques: interferometric
© European Southern Observatory (ESO), 1998