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22nd of October 2015
HI-deficient galaxies in intermediate density environments
by Helga Denes (CASS)
To gain a better understanding of how environment affects the gas content of galaxies, Denes et al. (2015) identified a sample of six HI-deficient galaxies from the HI Parkes All Sky Survey (HIPASS) using HI-optical scaling relations. One of the galaxies is located in the outskirts of the Fornax cluster, four are in loose galaxy groups and one is in a galaxy triplet. We present new high resolution HI observations with the Australia Telescope Compact Array (ATCA) of these galaxies. We discuss the possible cause of HI-deficiency in these galaxies based on HI observations and various multi-wavelength data. We find that the galaxies have truncated HI disks, lopsided gas distribution and some show asymmetries in their stellar disks. We conclude that both ram pressure stripping and tidal interactions are important gas removal mechanisms in low density environments. - The above figure shows color composite (rgb) images of the galaxies IC 1993, NGC 1515, NGC 6808, NGC 1473, NGC 6699 and ESO009-G010; the colours correspond to HI (red), DSS2 blue band (green) and GALEX NUV (blue).

Reference: Denes, Kilborn, Koribalski & Wong 2015, MNRAS, in press

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