NGC4632

Combined optical and radio image of polar ring galaxy candidate NGC 4632. Image Credit: J. English (U.Manitoba), with support of N. Deg (Queen’s U.) and the WALLABY team; CSIRO/ASKAP radio telescope, NAOJ/Subaru Telescope.

WALLABY_science_Hydra_cluster_2

HI countours from WALLABY (blue) overlaid on a Pan-STARRS image (grey-scale) of ESO 501−G075 near the edge of the Hydra cluster (Reynolds et al., 2021, MNRAS, 505, 1891). The galaxy displays an HI tail directed away from the cluster centre. Credit: Tristan Reynolds.

WALLABY_science_Hydra_cluster

WALLABY-detected galaxies in the Hydra cluster (Wang et al., 2021, ApJ, 915, 70). The HI column density images are shown in different slices of velocity offset from the cluster center (∆vrad) around the X-ray halo of Hydra (grey-scale). The column density images are enlarged by a factor of 5 for clarity. Credit: Jing Wang.

WALLABY_dark_galaxies_2

HI column density contours (left) and HI spectrum (right) of a dark HI cloud overlaid on a deep optical image from the DECam Legacy Survey (Wong et al., 2021, MNRAS, 507, 2905). The bright optical galaxy is a background object unrelated to the foreground HI cloud. Credit: Ivy Wong.

WALLABY_dark_galaxies_1

HI column density contours (left) and HI spectrum (right) of a dark HI cloud overlaid on a deep optical image from the DECam Legacy Survey (Wong et al., 2021, MNRAS, 507, 2905). The bright optical source near the cloud is an intervening foreground star. Credit: Ivy Wong.

All-sky map of HVCs

A false-colour all-sky map combining the column density and radial velocity of high-velocity neutral hydrogen gas detected by the HI4PI survey. Brightness corresponds to column density and hue to radial velocity.

Anti-centre complex

A comparison of the high-velocity neutral hydrogen gas detected by the Leiden/Argentine/Bonn (LAB) survey and the new HI4PI survey for the same region of the sky, showing the great improvement in resolution and spatial sampling of the new map.