EDP Sciences
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Volume 403, Number 2, May IV 2003
Page(s) 529 - 536
Section Galactic structure and dynamics
DOI http://dx.doi.org/10.1051/0004-6361:20030327

A&A 403, 529-536 (2003)
DOI: 10.1051/0004-6361:20030327

Structure and mass distribution of spiral galaxies at intermediate redshifts

A. Tamm1 and P. Tenjes1, 2

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

(Received 7 October 2002 / Accepted 25 February 2003)

Using the HST archive WFPC2 observations and rotation curves measured by Vogt et al. (1996), we constructed self-consistent light and mass distribution models for three disk galaxies at redshifts z=0.15, 0.90 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 M/LB = 4.4, 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 $M_{\odot} /\rm pc^3$. 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.

Key words: galaxies: photometry -- galaxies: fundamental parameters -- galaxies: high redshift -- galaxies: spiral -- galaxies: structure -- dark matter

Offprint request: P. Tenjes, ptenjes@ut.ee

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