The Deepest Radio Observations of Nearby Type IA Supernovae: Constraining Progenitor Types and Optimizing Future Surveys

We report deep radio observations of nearby Type Ia Supernovae (SNe Ia) with the electronic Multi-Element Radio Linked Interferometer Net-work (e-MERLIN), and the Australia Telescope Compact Array (ATCA). No detections were made. With standard assumptions for the energy densities of relativistic electrons going into a power-law energy distribution, and the magnetic field strength (∈e = ∈B = 0:1), we arrive at the upper limits on mass-loss rate for the progenitor system of SN 2013dy (2016coj, 2018gv, 2018pv, 2019np), to be MÛ ≤ 12 ¹2:8; 1:3; 2:1; 1:7º x 10-8M yr-1¹vw/100 km s-1º, where vw is the wind speed of the mass loss. To SNe 2016coj, 2018gv, 2018pv and 2019np we add radio data for 17 other nearby SNe Ia, and model their non-detections. With the same model as described, all 21 SNe Ia have MÛ ≤ 4 x 10-8M yr-1¹vw/100 km s-1º. We compare those limits with the expected mass loss rates in different single-degenerate progenitor scenarios. We also discuss how information on ∈rel and ∈B can be obtained from late observations of SNe Ia and the youngest SN Ia remnant detected in radio, G1.9+0.3, as well as stripped-envelope core-collapse SNe. We highlight SN 2011dh, and argue for ∈e ≈ 0:1 and ∈B ≈ 0:0033. Finally, we discuss strategies to observe at radio frequencies to maximize the chance of detection, given the time since explosion, the distance to the supernova and the telescope sensitivity.