The Tully--Fisher relation of cluster spirals at z = 0.83

We present the rest-frame B-band Tully—Fisher relation for a sample of 8 cluster spiral galaxies at z= 0.83 and 19 field spirals at z= 0.15–0.90 based on Very Large Telescope (VLT) spectroscopy and Hubble Space Telescope (HST) photometry. No strong difference is detected between the cluster and the field galaxies, but we find some evidence that the cluster spirals are ∼0.5–1 mag brighter than the field ones at a fixed rotation velocity. Although only a ∼1.5–2σ result, if confirmed with larger samples this effect could be caused by the cluster spirals experiencing a period of enhanced star formation while falling into the cluster.