| Popis: |
We present radio continuum observations of NGC 2082 using ASKAP, ATCA and Parkes telescopes frequencies from 888 MHz to 9000 MHz. Some 20 arc-sec from the centre of this nearby spiral galaxy, we discovered a bright and compact radio source, J054149.24–641813.7, of unknown origin. To constrain the nature of J054149.24–641813.7, we searched for transient events with the Ultra-Wideband-Low (UWL) Parkes receiver (704 MHz–4032 MHz coverage), and compare its luminosity and spectral index to various nearby supernova remnants (SNRs), and fast radio burst (FRB) local environments. Its radio spectral index is flat (α = 0.02 ± 0.09) which is unlikely to be either an SNR or pulsar. Also, we did not find a counterpart of this source at any other frequencies including HST, Spitzer and XMM-Newton X-rays. No transient events were detected with the Parkes telescope over three days of observations, and our calculations show J054149.24–641813.7 is two orders of magnitude less luminous than FRB 121102 & 190520Bs associated persistent radio sources — likely not bright enough to be a persistent radio source associated with an FRB. We conclude that the most likely origin for J054149.24–641813.7 is a background quasar or radio galaxy. Finally, we detect extended radio continuum emission that can be associated with the overall features of NGC 2082 itself. The spectral index of α = −0.15 ± 0.23 is somewhat unexpected for spiral galaxies, but consistent with thermal emission dominating across the galaxy. We explain that this rather flat radio spectral index is a consequence of NGC 2082’s radio quiet nucleus. |
