Chair: Ann Kathrin Baczko
Measuring RM variations with LOFAR: ISM vs ionosphere
Magnetic fields play a crucial role in the magneto-hydrodynamic (MHD) heating of the interstellar medium (ISM) and the density fragmentation of cold molecular clouds, thus regulating the process of star formation. They are also known to be important in particle ray acceleration, which can provide the pressure to drive galactic outflows. However, many important characteristics of the magnetic fields, such as their origin and evolution, strength and structure, and their influence on Galactic dynamics remain unknown. Using the data from highly polarized pulsars observed with German LOFAR stations, we will investigate long-term Rotation Measure (RM) variations. Our goal is to update our knowledge about the small-scale turbulent structure of the magnetic fields and the electron density in the ISM of our Galaxy. These variations arise as the pulsar moves along the tangent plane and, thus, the pulsar beam intersects different parts of the ISM. Besides being sensitive to the ISM effects due to LOFAR low-frequency range, our data are also susceptible to ionospheric effects that are undesirable for our investigation. Using long pulsars’ observations we can carefully investigate accuracy of the GPS ionospheric maps and independently estimate parameters of the noise, generated by imperfect ionospheric modeling. After careful subtraction of ionospheric contribution the residual RM data is expected to show the presence of red noise, whose parameters will depend on the regime of ISM turbulence.