Near-IR internetwork spectro-polarimetry at different heliocentric angles

¹ LERMA, Observatoire de Paris-Meudon, 5 place de Jules Janssen, 92195 Meudon, France e-mail: Marian.Martinez@obspm.fr
² Instituto de Astrofísica de Canarias, vía Láctea S/N, 31200 La Laguna, Spain e-mail: aasensio@iac.es
³ THEMIS-CNRS UPS 853, vía Láctea S/N, 31200 La Laguna, Spain e-mail: arturo@themis.iac.es

Received: 17 August 2007
Accepted: 26 October 2007

Abstract

Aims.The analysis of near infrared spectropolarimetric data at the internetwork in different regions on the solar surface could offer constraints that reject current modeling of these quiet areas.

Methods.We present spectro-polarimetric observations of very quiet regions for different values of the heliocentric angle for the Fe i lines at 1.56 μm, from disc centre to positions close to the limb. The spatial resolution of the data is . We analyse direct observable properties of the Stokes profiles as the amplitude of circular and linear polarisation, as well as the total degree of polarisation. The area and amplitude asymmetries are also studied.

Results.We do not find any significant variation in the properties of the polarimetric signals with the heliocentric angle. This means that the magnetism of the solar internetwork remains the same regardless of the position on the solar disc. This observational fact discards the possibility of modeling the internetwork as a network-like scenario. The magnetic elements of internetwork areas seem to be isotropically distributed when observed at our spatial resolution.