Spurious Radial Migration from Relativistic Effects in the Milky-Way
  Disk
  The gradient of the gravitational redshift in the potential of the Milky-Way
induces an apparent spurious radial migration. I show that this effect is
simply related to the local acceleration, which was measured recently by Gaia
eDR3, implying a spectroscopic shift of $[-2.4x10^{-2}/(r/8kpc)] km/s/kpc. The
transverse Doppler effect yields a comparable contribution. The spurious radial
velocity from both relativistic effects amounts to crossing a major portion of
the Milky-Way disk during the age of the universe, and must be corrected for in
any future measurement of the actual radial migration of stars.
