Tracing Magnetic Fields in IC 1954 with Velocity Gradient

Abstract

Magnetic fields, especially the magnetic braking effect, are crucial in transporting fuel materials to the galactic center and powering nuclear starbursts. To access the magnetic fields directly associated with molecular gas, we use the novel velocity gradient technique (VGT). By applying VGT to the high-resolution CO (2-1) emission lines obtained from the PHANGS-ALMA survey, we present the magnetic field orientation map for the galaxy IC 1954. With the advent of next-generation radio and spectroscopic observations from SKA and ngVLA, we discuss the promise of studying extragalactic magnetic fields at pc-scale.