High-resolution spectral imaging of supernova remnants with data from the Sardinia Radio Telescope

The remains of Supernova present a spectrum characterised by synchrotron emission from relativistic electrons in the radio band, and by high-energy emission of both lepton (Bremmstrahlung and inverse Compton processes) and hadron (neutral pion decay) origin. Hadronic emission is linked to the interaction between cosmic rays and thermal protons, while lepton processes occur through the interaction of radio electrons with photons in the surrounding environment.
For this reason, a co-spatial study of radio and gamma emissions is useful for better characterising the hadronic contribution in the high-energy part of the spectrum. Thanks to the performance of the Sardinia Radio Telescope in single-dish radio astronomical imaging observations and innovative imaging techniques based on On The Fly scans of extended sources, it has been possible to obtain images of the supernova remnants W44 and IC443 at three frequencies, 1.6, 7 and 22 GHz, highlighting the complex morphology of these celestial objects. Measuring the integrated fluxes in different frequency bands allows us to study the radio spectrum, characterising its impedance and verifying the presence of possible inversions. This is important for distinguishing between the lepton and hadron contributions in the gamma band of the spectrum and for further identifying Supernova Remnants as cosmic ray accelerators. Furthermore, the resolution of the images obtained allows us to study the spatial variation of the
parameters that characterise the radio spectrum and to evaluate the high-energy limit of the electron distributions associated with the different regions of physical interest in these Supernova Remnants.

Today, Astro Chiacchiere! is an informal meeting between the staff of the Cagliari Astronomical Observatory (staff, postdocs and students), which aims to discuss topics of a mainly scientific, technological and informative nature concerning the activities of the Observatory. The meeting is usually held on Tuesdays at 11:30 a.m. in the Auditorium of the Cagliari Astronomical Observatory. For information and/or contributions, please contact vvacca@oa-cagliari.inaf.it and surcis@oa-cagliari.inaf.it