« Using e-MERLIN to investigate the radio emission in nearby galaxies from AGN to star formation »
The nearby Universe (<150 Mpc) is rich with all types of galaxies, active galactic nuclei (AGN) and star formation (SF). Many of these galaxies have been the subject of large programmes in recent decades to better understand how galaxies evolve by way of feedback from AGN and SF processes across the multi-wavelength spectrum. The proximity of such galaxies make it possible to resolve individual sources in order to study the AGN activity or SF processes such as supernova remnants (SNR). Multi-wavelength studies have made it possible to search for correlations in the data to better understand the causal links between emission processes and their observational characteristics. But radio data has often not been used due to the complexity of the data analysis involved or the need for high performance computing to analyse such data. In this seminar, I will discuss the use of high-resolution very long baseline interferometry in the centimetre band with the e-MERLIN radio array to study nearby galaxies. I will focus first on the results of the LeMMINGs survey: a large statistically-complete sample of nearby galaxies at 1.5 and 5 GHz to probe the AGN activity in Seyferts, LINERs and HII galaxies. I will highlight the cases of NGC 4151 and NGC 1068, two archetypal Seyferts with large-scale jets. I will also discuss the nearby starburst galaxy M82, which has 40 years of monitoring of the nearly 100 SNRs and HII regions within it as well as some more exotic transient sources. Finally, I will make the case for making widefield images of radio data, which will prove fruitful for further scientific discovery but also be necessary in the era of the Square Kilometre Array where raw data will not be kept long term.