Daily Image
09-02-2009
The Parkes Galactic Meridian Survey (PGMS)
| Submitter: | Marijke Haverkorn |
| Description: | Magnetic fields thread the interstellar medium of our Galaxy. Although these fields are weak (of order microGauss), their pressure is comparable to cosmic ray and turbulent gas pressure, making Galactic magnetic fields a fundamental component of the Galactic ecosystem. Galactic magnetism influences star formation, accelerates cosmic rays and controls gas dynamics and interstellar turbulence. Despite this, little is known about the detailed structure and strength of the Galactic magnetic field. Observations can only be done indirectly and typically probe only one field component, or under certain physical conditions. Including magnetic fields in e.g. compressible turbulence theory is hard, and taking them into account in numerical simulations is very expensive. However, golden times lie ahead for Cosmic Magnetism research: the spectro-polarimetric capabilities of the next generation radio telescopes such as LOFAR and SKA will enable us to take a fresh look at the magnetized sky. This image shows one frequency slice in a spectro-polarimetric survey at 2.3 GHz conducted with the Parkes single dish telescope. The Parkes Galactic Meridian Survey (PGMS, Carretti et al 2009, Haverkorn et al 2009) probes the polarized Galactic radio emission along a meridian from the Galactic plane to the Galactic south pole in order to study the evolution of Galactic interstellar magnetism and polarization from the plane into the halo. The image shows Stokes I, Q, U, and V maps of the 30 degrees in latitude closest to the Galactic plane. The ubiquitous structures in linear polarization (Stokes Q and U) do not correspond to emission structures in total intensity (Stokes I), indicating that they are caused by depolarization and Faraday rotation due to interstellar magnetic fields. |
| Copyright: | Carretti, Haverkorn, McConnell, Bernardi, McClure-Griffiths, Cortiglioni, Poppi |
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