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تسجيل مستخدم جديدInternal Kinematics of Spiral Galaxies in Distant Clusters
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We present first results from our project to examine the internal kinematics of disk galaxies in 7 rich clusters with 0.3<=z<0.6. Spatially resolved MOS spectra have been obtained with FORS at the VLT. We concentrate here on the clusters MS1008.1-1224 at z=0.30 and Cl0413-6559 (F1557.19TC) at z=0.51. Out of 22 cluster members, 12 galaxies exhibit a rotation curve of the universal form rising in the inner region and passing over into a flat part. The other members have intrinsically peculiar kinematics. The 12 cluster galaxies for which a maximum rotation velocity could be derived are distributed in the Tully-Fisher diagram very similar to field galaxies from the FORS Deep Field with corresponding redshifts. The same is true for 6 galaxies observed in the cluster fields that turned out not to be members. In particular, these cluster spirals do not show any significant luminosity evolution as might be expected from certain clusterspecific phenomena. Contrary to that, the other half of the cluster sample with disturbed kinematics also shows a higher degree of structural assymetries on average indicating ongoing or recent interaction processes.
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We introduce our project on galaxy evolution in the environment of rich clusters aiming at disentangling the importance of specific interaction and galaxy transformation processes from the hierarchical evolution of galaxies in the field. Emphasis is
laid on the examination of the internal kinematics of disk galaxies through spatially resolved MOS spectroscopy with FORS at the VLT. First results are presented for the clusters MS1008.1-1224 (z=0.30), Cl0303+1706 (z=0.42), and Cl0413-6559 (F1557.19TC) (z=0.51). Out of 30 cluster members with emission-lines, 13 galaxies exhibit a rotation curve of the universal form rising in the inner region and passing over into a flat part. The other members have either intrinsically peculiar kinematics (4), or too strong geometric distortions (9) or too low S/N (4 galaxies) for a reliable classification of their velocity profiles. The 13 cluster galaxies for which a maximum rotation velocity could be derived are distributed in the Tully--Fisher diagram very similar to field galaxies from the FORS Deep Field that have corresponding redshifts and do not show any significant luminosity evolution with respect to local samples. The same is true for seven galaxies observed in the cluster fields that turned out not to be members. The mass-to-light ratios of the 13 TF cluster spirals cover the same range as the distant field population indicating that their stellar populations were not dramatically changed by possible clusterspecific interaction phenomena. The cluster members with distorted kinematics may be subject to interaction processes but it is impossible to determine whether these processes also lead to changes in the overall luminosity of their stellar populations.
We present our project on galaxy evolution in the environment of distant rich clusters aiming at disentangling the importance of specific interaction and galaxy transformation processes from the hierarchical evolution of field galaxies. Spatially res
olved MOS spectra were gained with VLT/FORS to analyze the internal kinematics of disk galaxies. First results are shown for the clusters MS 1008.1-1224 (z=0.30), Cl 0303+1706 (z=0.42), and Cl 0413-6559 (z=0.51). Out of 35 late type cluster members, 13 galaxies exhibit a rotation curve of the universal form rising in the inner region and passing over into a flat part. The other members have peculiar kinematics. The 13 cluster galaxies for which a maximum rotation velocity could be derived are distributed in the Tully-Fisher diagram very similar to field galaxies from the FORS Deep Field with corresponding redshifts. The same is true for seven non-cluster galaxies observed in the cluster fields. The TF-cluster spirals do not show any significant luminosity evolution as might be expected from certain clusterspecific phenomena. Contrary to that, the disturbed kinematics of the non--TF cluster spirals indicate ongoing or recent interaction processes.
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