Structure and mass distribution of spiral galaxies at intermediate redshifts

¹ Institute of Theoretical Physics, Tartu University, Tähe 4, Tartu 51010, Estonia e-mail: atamm@ut.ee
² Tartu Observatory, Tõravere, Tartumaa 61602, Estonia

Corresponding author: P. Tenjes, ptenjes@ut.ee

Received: 7 October 2002
Accepted: 25 February 2003

Abstract

Using the HST archive WFPC2 observations and rotation curves measured by Vogt et al. ([CITE]), we constructed self-consistent light and mass distribution models for three disk galaxies at redshifts and 0.99. The models consist of three components: the bulge, the disk and the dark matter. The light distribution of the galaxies in the outer parts is steeper than a simple exponential disk. Spatial density distribution parameters for the components were calculated. After applying k-corrections, mass-to-light ratios for galactic disks within the maximum disk assumption are , 1.2 and 1.2, respectively. Corresponding central densities of dark matter halos within a truncated isothermal model are 0.0092, 0.028 and 0.015 in units . In addition, we constructed mass distribution models without a dark matter component. Due to the limited extent of rotational curves the models without a dark halo fit equally well with observations. In this case mass-to-light ratios for galactic disks are 5.5, 3.3 and 2.1, respectively.