Polarized radio emission of nearby spiral galaxies with NVSS

RODRÍGUEZ KAMENETZKY, ADRIANA; VALOTTO, CARLOS

Sao Paulo, Brasil

Workshop; School on Fundamental Astrophysics, ICTP-SAIFR,; 2013

ICTP South American Institute for Fundamental Research

We present a systematic study of radio emission of a set of nearby spiral galaxies. The data was obtained from NVSS (NRAO VLA Sky Survey, λ=20cm), containing information about Stokes parameters that describes the polarization states of radiation. In order to characterize the detected radio emission, we developed a ?numerical classification? that allows the identification of main features, e.g extended or localized emission, presence or absence of polarization. This classification permits a simple examination of the possible dependence of the emission detected with parameters such as morphological types and dimensions. Since linearly polarized emission traces the ordered magnetic fields, we inspected the sample to establish the conditions under which it is possible to obtain information on this fields with data provided by NVSS. We studied the relation between the radio emission, optical structure, and detected magnetic fields , when the signal over 2σ were significant. The obtained results are in agreement with previous works, based on specific studies with better resolution.