DEEP HDF astrometry page describes the procedure used
in the astrometric solution.
The photometry for most objects results from integrating the light
within circular apertures out to 3 arc sec, as described by
Phillips et al. (1997). For the 51 compact galaxies
that were analysed by Phillips et al. (1997) and
Guzmán et al. (1997), the I814 magnitudes were recalculated
using elliptical apertures out to 8 arc sec.
In the database no
discrimination between both measures is made at present.
Colours in the HDF used the photometry available in the
catalog of Version 1 Drizzled HDF images.
For the Flanking Fields, colours were obtained using
V band images . The latter was calibrated
using HDF galaxies in common, as described by
Phillips et al. 1997, ApJ 489, 543. To obtain
(V606-I814) colours were it was necessary to calculate
a transformation relating the V606 - I814 colours with
V(LRIS)- V606, because of the different bandpasses of the
LRIS V and HST V606 filters. This transformation,
calculated by R. Guzmán, is shown in the figure below.
The HST images were degraded until their seeing matched that of
the ground-based images. The magnitude were then calculated
using 1.12 arc sec.
The transformation itself is denoted by the solid line in the plot.
A postscript version
of this plot is also available.
Last modified: Thu Feb 18 17:26:23 1999