Astron. Astrophys. Suppl. Ser. 133, 387-399
A.C. Katsiyannis1 - S.N. Kemp2 - D.S. Berry1 - J. Meaburn1
1 - Department of Physics and
Astronomy, University of Manchester, Oxford Rd., Manchester M13 9PL, UK
2 -
Instituto de Astrofísica de Canarias, C/ Via Lactea, E-38200 La Laguna,
Tenerife, Spain
Received February 23; accepted April 24, 1998
We have digitally co-added APM scans of 13 Kodak TechPan films of
the SE region of the Virgo cluster of galaxies. The 
field of the R-band films combined with
the resolution of 
arcsec pixel-1 results in data
file sizes of about 222 MBytes. The 13 scanned films have been
aligned, co-added, corrected for vignetting effects and cleaned of
stellar features. To illustrate the astrophysical uses of this
technique, we present high contrast images of a sample of Virgo
cluster and background galaxies. Several very faint, but very
clearly seen features, such as the interaction between IC 3481, IC
3481A and IC 3483 and filaments outside of the common envelope of
NGC 4438 & NGC 4435, can be seen for the first time. We present an
image of the halo of M 87 showing its great extent, and an image of
the central regions of the cluster which shows no real evidence for
interactions between the galaxies in this region. We also present
high-quality images of the previously-identified "jet" and shell
features around M 89. We also present an image of the whole field
which appears to show large variations in brightness of the
intra-cluster medium across the region, with the brightest regions
in the northern part in the central regions of the cluster, though
we caution against this interpretation until we have investigated
the large variation in emulsion sensitivity across individual films
more thoroughly.
Key words: techniques: image processing -- galaxies: structure -- galaxies: haloes -- galaxies: interactions -- galaxies: clusters: Virgo cluster
Copyright The European Southern Observatory (ESO)