Characterizing Magnetic Fields’s Role in Fueling Seyfert Nuclei With SOFIA/HAWC+, Velocity Gradient, and VLA
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Yue Hu
University of Wisconsin
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Molecular gas is considered to be the primary source of fuel for star formation and nuclear activity in Seyfert galaxies. To investigate the role of magnetic fields in guiding molecular gas towards the nucleus, it is necessary to measure the magnetic fields that are embedded in cold molecular gas. In this study, we present magnetic field maps for four nearby galaxies - M51, NGC 3627, NGC 1068, and NGC 1097 - based on dust polarization data from the SOFIA/HAWC+ SALSA survey and synchrotron polarization data from the VLA. We have also applied a new velocity gradient technique (VGT) to CO isotopolog data from the ALMA and the PAWS survey to separate the magnetic fields that are directly associated with molecular gas. Comparison of the magnetic fields inferred from different methods reveals rich information about Seyfert activity. The good alignment between the magnetic fields traced by VGT-CO and by VLA synchrotron polarization supports the correlation between star formation and cosmic-ray generation. We have found a local misalignment between the magnetic fields traced by CO and HAWC+ 89um dust polarization within the nuclear ring of NGC 1097, where the former aligns with the central bar's orientation. This misalignment indicates different magnetic field configurations in different gas phases and serves as an observational diagnostic for the ongoing multiphase fueling of Seyfert activity.

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