Annu. Rev. Astron. Astrophys. 2000. 38: 667-715 Copyright © 2000 by Annual Reviews. All rights reserved

4.5. Galaxy Kinematics

Spectroscopy of galaxies in the HDF-N has provided kinematical information leading to constraints on mass and/or luminosity evolution. [Phillips et al. 1997] and [Guzman et al. 1997] observed 61 compact, high-surface-brightness galaxies (r < 0".5) in the HDF-N flanking fields. The great majority show emission lines and have redshifts 0.4 < z < 1. Masses for the systems were deduced from the line widths, which ranged from 35 - 150 km s^-1, and one-half of the sample were found to be low mass (M < 10¹⁰ M), relatively luminous systems similar to local H II galaxies. The remaining systems were a heterogeneous class similar to local starburst galaxies.

[Vogt et al. 1997] studied a separate magnitude-limited sample of eight high-inclination disk galaxies from the HDF-N flanking fields in the redshift range 0.15 < z < 0.75. Reliable velocity information could be discerned to three disk scale-lengths, comparable to the extent of optical rotation curves for local galaxies. Results from this survey were combined with an earlier survey of more luminous galaxies [Vogt et al. 1996] to study the Tully-Fisher (TF) relation at z ~ 0.5 over a span of 3 magnitudes. A luminosity-line-width relation exists for the sample, linear and of the same slope as the local TF relation, but shifted to higher luminosities by 0.4 magnitudes. This is similar to the results from other studies [Forbes et al. 1996, Bershady 1997] but larger amounts of luminosity evolution were seen in other samples [Rix et al. 1997, Simard & Pritchet 1998]. [Vogt et al. 1997] speculate that the differences are due to sample selection. In any case, the modest luminosity evolution is consistent with the modest surface-brightness evolution found in the analysis of structural parameters by [Simard et al. 1999].