EDP Sciences
Free Access
Volume 387, Number 1, May III 2002
Page(s) 82 - 97
Section Galactic structure and dynamics
DOI https://doi.org/10.1051/0004-6361:20020285

A&A 387, 82-97 (2002)
DOI: 10.1051/0004-6361:20020285

Towards a model of full-sky Galactic synchrotron intensity and linear polarisation: A re-analysis of the Parkes data

G. Giardino1, A. J. Banday2, K. M. Górski3, 4, K. Bennett1, J. L. Jonas5 and J. Tauber1

1  Research and Science Support Department of ESA, ESTEC, Postbus 299, 2200 AG Noordwijk, The Netherlands
2  Max-Planck Institut für Astrophysik, Garching bei München, 85741, Germany
3  ESO, Garching bei München, 85748, Germany
4  Warsaw University Observatory, Warsaw, Poland
5  Department of Physics & Electronics, Rhodes University, PO Box 94, Grahamstown 6140, South Africa

(Received 21 December 2001 / Accepted 22 February 2002 )

We have analysed the angular power spectra of the Parkes radio continuum and polarisation survey of the Southern galactic plane at 2.4 GHz. We have found that in the multipole range l=40-250 the angular power spectrum of the polarised intensity is well described by a power-law spectrum with fitted spectral index $\alpha_{L} = 2.37 \pm 0.21$. In the same multipole range the angular power spectra of the E and B components of the polarised signal are significantly flatter, with fitted spectral indices respectively of $\alpha_{E} = 1.57 \pm 0.12$ and $\alpha_{B} = 1.45\pm
0.12$ . Temperature fluctuations in the E and B components are mostly determined by variations in polarisation angle. We have combined these results with other data from available radio surveys in order to produce a full-sky toy model of Galactic synchrotron intensity and linear polarisation at high frequencies ( $\nu \ga
10$  GHz). This can be used to study the feasibility of measuring the Cosmic Microwave Background polarisation with forthcoming experiments and satellite missions.

Key words: radio continuum: ISM -- surveys -- polarization -- cosmic microwave background

Offprint request: G. Giardino, ggiardin@rssd.esa.int

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