Richard Bower; Ian Smail; Mark Sullivan; Mark Swinbank: ICC, University of Durham
Andy Bunker; Joanna Smith: University of Cambridge
Richard Ellis; Graham Smith; Jean-Paul Kneib: Caltech Astronomy
HST image of cluster A2218
HST image of cluster A2218 (ra 66:35:49, dec +66:12:45)
Left: Arc #289 in A2218 generated by combining HST WFPC2 B, V and I drizzled images. Right: The reconstructed image of the arc corrected for lens magnification using the mass model of Smith et al. (2003).
Sky Frame
Source Frame Left: The [OII] emission
map of the arc measured from the GMOS IFU observations. The
distribution of [OII] flux agrees well with the UV flux seen in the HST
images above (the seeing for the observations was 0.7"). The contour
map of the derived velocity field is overlaid. Right: The
reconstructed IFU velocity field of the galaxy. The red and blue
regions represent redshift and blueshift respectively and the contours
map the velocity. The luminosity weighted magnification is 4.92 but
varies from ~5.6 to ~4.9 from the northern to southern end of the arc.
Without a lens, at z=1, 1" corresponds to 7.7kpc
Sky Frame
Source Frame Arc 289 on the Tully Fisher Relation
Left: Arc\#289 on the Tully-Fisher relation in rest
frame B-band compared to high redshift (z~0.83) field galaxies
(Milvang-Jensen et al. 2001) and the high redshift sample from Vogt
et al. (1999). For comparison we show the low redshift local fit
from Pierce & Tully (1992). The solid triangle shows a massive disk
galaxy (L451) at z=1.34 (van Dokkum & Stanford 2001). The galaxy
rotation curve (inset) shows the peak-to-peak rotation velocity of
the arc in [OII] emission built from the IFU image in the
source plane. The error bars shown are formally 3-\sigma and
alternate points are independent. The horizontal error bars show
0.7'' seeing transformed to the source plane. Right: The rest
frame I-band Tully-Fisher relation compiled from Mathewson & Ford
(1992) and from the Ursa-Major Cluster (Verheijen 2001). Arc #289 is
shown by the solid point and lies very close to the mean TF relation
for present day spirals. The small change in the I-band magnitude
shown by arc#289 suggests a preference for hierarchical rather than
the ``classical'' formation model.