A Westerbork blind HI imaging survey og the Perseus-Pisces filament in the Zone of Avoidance

Abstract: Based on the systematic HI follow-up survey of 2MASS bright galaxies in the Zone of Avoidance (ZoA) with the Nançay Radio Telescope (NRT), a prominent galaxy overdensity crossing the Galactic Plane at longitudes of ~160° was uncovered. This filamentary overdensity is part of the expansive Perseus-Pisces Supercluster (PPS; cz ~ 6000 km/s). Within it an X-ray galaxy cluster mostly known as the 3C 129 cluster is embedded. The cluster hosts two strong radio galaxies with bent morphologies, which is indicative of a rich intracluster medium. Despite it being a potentially rich cluster and part of the larger PPS, very little was known about its galaxy composition because of the high Galactic dust extinction in the ZoA. The Westerbork Synthesis Radio Telescope (WSRT) was used to blindly map this ZoA crossing of the PPS in the 21 cm HI-wavelength. The survey was conducted through 35 individual pointings observed for a total of 420 hours, covering a large area of about 9.6 sq.deg and a velocity range of approximately cz ~ 2000 – 16000 km/s. Over 200 galaxies were detected in HI distributed over various substructures, covering a range of cosmic environments within the survey volume. In this talk I will present results
of this survey and show how the galaxies are distributed and connected to the large scale structures above and below the ZoA. I will also present properties of the galaxy population in the 3C 129 cluster and give an overview of the properties of the HI gas in galaxies situated in various environments which range from dense cluster cores, galaxy groups to nearly empty voids.