Speaker
Description
Diffuse radio emission has been observed in plenty of galaxy clusters and classified in radio halos, relics or radio phoenices depending on its morphological and spectral properties. A category that is still less widely studied is that of radio phoenices.
These sources are typically characterised by an irregular and filamentary morphology with an ultra-steep radio spectrum ($\alpha\ge1.5-2$). They are thought to trace fossil lobes of radio galaxies that have been re-energised by adiabatic compression after the passage of a shock wave. However, their precise origin and connection to shocks is still uncertain.
To investigate in more details the radio morphology of these sources we have decided to exploit the very high resolution and sensitivity of LOFAR VLBI observations at 144 MHz.
In this talk, I will present the LOFAR high resolution images of the clusters A1914 and A566. At sub-arcsecond resolution the emission of the radio phoenix in the cluster A1914 is highly filamentary: it presents two bright filamentary structures with many parallel filaments connecting them, while other filaments elongates in different directions in the ICM. The radio phoenix in the cluster A566 also presents filamentary emission resembling the ``mushroom-shape'' structure observed in the galaxy group Nest200047 (Brienza et al. 2021). The flat surface brightness profiles of the filaments suggest they are generated by compression of magnetic field lines. However, it is still unclear whether these filaments reflect the internal magnetic field structure of the remnant radio lobes or magnetic fields in the intracluster medium. Inquiring the origin of these filaments could therefore help us to make a step forward on the comprehension of radio phoenices formation.
| What is your career stage? | Non-tenured scientist (post PhD) |
|---|---|
| Which telescopes do you use / are you affiliated with? | LOFAR |
