VLA observations of the giant radio galaxy 3C 449

In this paper we present multifrequency VLA observations of the giant radio galaxy 3C 449. High resolution and sensitivity data were obtained in total intensity and polarized flux at 1.365, 1.445, 1.465, 1.485, 4.685, 4.985 a nd 8.385 GHz. The source is characterized by an unresolved core, two opposite symmetric j ets, and very extended lobes. These new images show the source morphology i n great detail, in particular we detect plumes and wiggles in the low brigh tness lobes. The source is considerably polarized at all frequencies. We fi nd that the magnetic field orientation is parallel to the jet axis at the v ery beginning of the jet, and becomes perpendicular at about 10"(5 kpc) fro m the core. In the low brightness regions, the magnetic field is circumfere ntial to the edges of the emission region. The spectral index map between 5 GHz and 8.4 GHz shows that the northern re gion beyond 1' from the core has a much flatter spectrum than the southern one. We analyse the jet dynamics, and conclude that the jets are relativistic at the beginning, and decelerate significantly within 10"(5 kpc) from the cor e. We compute the rotation measure, using all seven frequencies between 1.4 an d 8.4 GHz. We detect significant rotation measure with values within about +/- 50 rad m(-2) of the expected contribution of our Galaxy. The Faraday ef fect is likely to originate in an external screen, which is most probably t he intergalactic medium of the group of galaxies around 3C 449. Moreover, w e resolve the effect of the interstellar medium associated with the galaxy 3C 449 itself.