Coffee talks
Friday 25/02/2022 @ 11:30, On-line - meet.google.com/sue-bwvk-axf
Alessandro Ignesti (INAF - Osservatorio Astronomico di Padova), "The LOFAR-MeerKAT-VLA View on the Nonthermal Side of a Jellyfish Galaxy"
Ram pressure stripping is a crucial evolutionary driver for cluster spiral galaxies. It can accelerate their evolution by triggering the interplay between the interstellar (ISM) and intracluster (ICM) mediums, and by dissipating their gas reservoir. Radio observations can shed new light in this field by probing the magnetic fields, which can drive the evolution of the stripped gas, and the relativistic electron populations, whose properties are connected to the star formation history. Here we present the results of a LOFAR-MeerKAT-VLA multi-frequency study of the non-thermal radio emission of a jellyfish galaxy JW100 in the cluster Abell 2626. We analyzed the non-thermal spectra within the stellar disk, the stripped tail and the central AGN from 0.144 to 5.5 GHz, as well as mapped the spectral index over the galaxy. We constrained the magnetic field intensity to be between 11 and 18 ?G in the disk and <10 ?G in the tail. Our study reveals that the radio emission within the stellar disk is dominated by a radiatively old plasma, whose origin is related to an older phase of high star formation rate. This suggests that the star formation quickly declined by a factor of 4 in a few 107 yr. The radio emission in the tail is consistent with the stripping scenario, where the radio plasma originally accelerated in the disk is then displaced in the tail. Finally, by combining radio, optical and X-ray observations we provide a holistic picture of the complex ICM-ISM interplay taking place in this galaxy.