Abstract.
An apparent intergalactic HI cloud of enormous spatial extent (approx. 125
x 80 kpc /h for D = 29 Mpc/h) has been serendipitously detected between the
peculiar galaxies NGC~3256 and NGC~3263 in spectral-line images of the
merging galaxy system NGC~3256. It was subsequently confirmed in follow-up
observations toward NGC~3263 which is an edge-on galaxy displaying an
extended tidal tail in the direction away from the cloud. Each galaxy system
was observed using 3 configurations of the Australia Telescope Compact Array.
Single-dish HI observations of the apparent cloud with the 64-m Parkes Radio
Telescope show a peaked emission feature with a FWHM of approx 140 km/s.
Assuming this peaked feature is emission from a spatially isolated cloud gives
a preliminary estimate of a few times 10^9 Msun/h^2 for its HI mass.
The ATCA and Parkes observations are presented along with a brief description
of our on-going observational campaign (e.g. the cloud appears to be detected
in the optical V bandpass). Further analysis of the multi-frequency data may
allow us to determine whether the cloud is tidal debris or a primordial ``gas
puddle''
Keywords. galaxies: individual (NGC 3256) - galaxies: neutral gas