We present VLA H I imaging data for a field in the NW of the galaxy cluster Abell 1367 (z = 0.02) in an attempt to probe the effect environment has on the interstellar medium of late-type spiral galaxies. Several galaxies show pronounced tails and as
ymmetries, and 7 out of 10 show significant, several kpc offsets between the HI centroid and the optical. We compare our results against a sample of optically bright, late-type galaxies (spirals) across the central 1.5 Mpc of the cluster taken from the Arecibo Galaxy Environment Survey (AGES). We calculate the H I deficiency and find that the expected global trend for the H I deficiency of these spirals to increase with projected proximity to the cluster core, seen in clusters like Coma and Virgo, is not observed. We classified the spirals into four evolutionary states, with the galaxies in each state sharing a similar degree of H I deficiency and optical colour. The common characteristics of the spirals in each evolutionary state suggests they have been subject to similar environmental processes. Many of the spirals in the most common evolutionary state (moderate H I deficiency and blue colour) have an H I intensity maximum which is displaced relative to its optical counterpart. The orientation of these offsets and magnitude of their H I deficiencies together with data from other wavelengths provide observational evidence in support of varying degrees of ram pressure stripping and tidal interaction. In general, our results indicate that the H I disks of bright late-type galaxies in the central part of the cluster are subject to both gas loss and morphological disturbance as a result of their interaction with the cluster environment. This provides further observational evidence of a more complex environment in Abell 1367 as compared to Virgo and Coma.
Based on a VLA HI-imaging through the total volume of the cluster Abell 85, we compare the distribution of HI-rich and HI deficient late type galaxies with the intra cluster medium (ICM) drawn by the X-ray emission.
This series of papers explores the evolution of late-type galaxies in the rich cluster Abell 85. Here, we revisit the complex dynamical state of A 85 by using independent methods. We analyze the redshift distribution towards the cluster out to 40,000
km/s, and determine the mean redshifts of the background clusters A 87 and A 89. We then search for substructures in A 85 by considering the 2-D galaxy distribution for its members and by applying the kinematical 3-D Delta-test to both projected positions and radial velocities. This clearly reveals several substructures that we describe. We also analyse the distribution of the brightest blue galaxies across a major fraction of the cluster volume, considering if they are gas-rich or poor. We report a very asymmetric distribution of the blue member galaxies, and connect it with substructures revealed in the optical and X-rays. By matching our sample of bright blue member galaxies with HI detections reported in the literature, we identify gas-rich and gas-poor ones. HI-rich blue galaxies also turn out to be asymmetrically distributed, with most of them projected on the eastern side of the cluster. No blue objects have been detected in HI up to a projected radius of 2 Mpc in this zone. We estimate the ram pressure stripping exerted by the intra-cluster medium as a function of the projected distance from A 85, and quantify how important this mechanism may be in sweeping the gas out of the infalling spirals.
