Concerning the limit on the mean mass distribution of galaxies from their gravitational lens effect

The importance of the assumption of infinite background-galaxy distance in the determination of galactic mass-distribution bounds from gravitational lens effects by Tyson et al. (1984) is investigated analytically. The upper bounds on rotational velocity are found to be significantly increased when the actual distance distribution is taken into account. The upper limit on the rotational velocity of an L(asterisk)-galaxy untruncated isothermal halo, for example, would be 330 km/s. 6 references