A T N F    D a i l y    A s t r o n o m y    P i c t u r e

17th of May 2021
WALLABY observations of the Hydra I cluster
by Reynolds et al.
Reynolds et al. present results from neutral atomic hydrogen (HI) observations of the Hydra I cluster taken as part of the Widefield ASKAP L-band Legacy All-sky Blind Survey (WALLABY). The Hydra I cluster is located ~60 Mpc (about 200 million light years) away and contains 581 optically detected galaxies. Reynolds et al. find that 51 galaxies are detected in HI emission within the cluster. Of the 51, five galaxies are found to be large enough (i.e., sufficiently spatially resolved) to allow detailed kinematic and mass model analysis. Reynolds et al. consider in detail one of these, ESO 501−G075, that lies near the edge of the cluster and displays an HI tail directed away from the cluster centre. They conclude that, ESO 501−G075 is likely recently infalling into the cluster and in the early stages of experiencing ram pressure.

The image shows a Digitized Sky Survey (DSS) grey-scale image of the Hydra I cluster with the 51 ASKAP detections shown by the blue/red contours. The 5 galaxies with red contours are those that are well spatially resolved: ESO 501−G075 is at the centre of the orange dot-dashed circle. The black star and dashed circle indicate the centre and virial radius of the Hydra I cluster. The diagonal grey line in the lower left corner is an artefact in the DSS image. The large HI contour to the lower right is an interacting galaxy group.

<<   |   archive   |   about   |   today   *   ATNF   |   Parkes   |   ATCA   |   Mopra   |   VLBI   |   ASKAP   |   >>