Bending Waves in Velocity Space: a First Look at the THINGS sample

Understand

Detection of bending waves is a highly challenging task even in nearby disc galaxies due to their sub-kpc bending amplitudes.

• However, simulations show that the harmonic bending of a Milky Way like disc galaxy is associated with a harmonic fluctuation in the measured line of sight (los) velocities as well, and can be regarded as a kinematic signature of a manifested bending wave.
• Here, we look for similar kinematic signatures of bending waves in \HI discs, as they extend to much beyond the optical radii.
• We present a multipole analysis of the \HI los residual velocity fields of six nearby spiral galaxies from the THINGS sample, which uncovers the bending wave-induced velocity peaks.