With J. Richard Fisher , he proposed the Tully -- Fisher relation , which shows that the luminosity of a galaxy and the orbital velocities of its stars are correlated .
Born in Toronto , Ontario , Canada , Tully 's specialty is the astrophysics of galaxies .
With J. Richard Fisher , Tully proposed the Tully -- Fisher relation , which shows that the luminosity of a galaxy and the orbital velocities of its stars are correlated .
Born in Toronto , Ontario , Canada , Tully 's specialty is the astrophysics of galaxies .