New Radio Observations of Edge-On Galaxies, NGC 2683 and NGC 3044
Cook, Tanden K.
radio continuum emission , radio interferometry , spiral galaxies , magnetic fields , polarization
This thesis presents new radio continuum observations at S band of two edge-on galaxies, NGC 2683 and NGC 3044. These observations were obtained by the CHANG-ES consortium using the C-array configuration of the Karl G. Jansky Very Large Array (VLA). All data reduction and imaging was performed using the Common Astronomy Software Applications (CASA) software provided by the National Radio Astronomy Observatory (NRAO). Total intensity, polarization intensity, and magnetic field vectors are mapped to provide a better understanding of the radio halos surrounding spiral galaxies. In addition to the new S band observations, previous L and C band observations from the CHANG-ES consortium are revisited. Attempts to combine all three bands were successful for each galaxy, with both the combined and uncombined total intensity maps reaching a sub-3 μJy/beam RMS noise. To our knowledge, this is the first time any galaxy has been observed over such a large, nearly contiguous bandwidth at radio wavelengths. From the resultant polarization maps of NGC 2683 and NGC 3044, we observe the magnetic field structure out to ~3 kpc and ~7 kpc above the mid-plane respectively. In both galaxies the magnetic field structure is found to be different from the standard "X-shaped" field expected of edge-on spiral galaxies. Polarization fraction maps were also made for each galaxy using the S band data. Despite the difference in star formation rate, each galaxy has a nearly identical total polarization fraction.