Dual differential polarimetry. A technique to recover polarimetric information from dual-polarization observations
Artikel i vetenskaplig tidskrift, 2016

Current mm / submm interferometers, like the Atacama Large mm / submm Array (ALMA), use receivers that register the sky signal in a linear polarization basis. In the case of observations performed in full-polarization mode (where the cross-correlations are computed among all the polarization channels) it is possible to reconstruct the full-polarization brightness distribution of the observed sources, as long as a proper calibration of delay off sets and leakage among polarization channels can be performed. Observations of calibrators, preferably with some linear polarization, with a good parallactic angle coverage are usually needed for such a calibration. In principle, dual-polarization observations only allow us to recover the Stokes I intensity distribution of the sources, regardless of the parallactic angle coverage of the observations. In this paper, we present a novel technique of dual differential polarimetry that makes it possible to obtain information related to the full-polarization brightness distribution of the observed sources from dual-polarization observations. This technique is inspired in the Earth-rotation polarization synthesis and can be applied even to sources with complex structures.

techniques: interferometric

instrumentation: interferometers

techniques: polarimetric

Författare

Ivan Marti-Vidal

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

Wouter Vlemmings

Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik

Sebastien Muller

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 593 Art no A61- A61

Ämneskategorier

Astronomi, astrofysik och kosmologi

Fundament

Grundläggande vetenskaper

DOI

10.1051/0004-6361/201628225