Coffee talks
Friday 25/03/2022 @ 11:30, On-line - meet.google.com/sue-bwvk-axf
Francesca Loi (INAF-OAC), "A depolarizing HI tidal tail in the western lobe of Fornax A"
Recent MeerKAT HI observations of Fornax A reveal tidal material intersecting in projection the western lobe of this radio galaxy. We found a spatial coincidence between the northern HI tail and a depolarized structure observed for the first time with the Australian Square Kilometre Array Pathfinder (ASKAP) at 1.2 GHz. We analyzed the properties of the rotation measure (RM) image obtained with ASKAP data at the location of the HI tail and in its neighborhood. According to our results, the two regions host magnetic fields with different power spectra. The RM found at the location of the HI tail cannot be explained in terms of a Faraday screen due to the Fornax cluster and/or to the Fornax A intra-group, and there is a clear excess with respect to the neighborhood. We determined that the HI tail is hosting a magnetic field with a strength of the order of ?9.5?11 ?G. The spatial coincidence between HI tail and depolarization analyzed in this work could be the first observed evidence of a magnetic field that either has passed through a radio galaxy lobe or has survived the lobe expansion.