DOI

https://doi.org/10.48717/aszj-j230

Project

RG012

Title

EVN obserations of recurrent nova RS Oph at 5 GHz

Abstract

Fifteen years after its previous outburst, the symbiotic recurrent nova RS Oph exploded again on 2021 Aug 8th, its first outburst during the Fermi era. In symbiotic novae, the material ejected from the surface of the white dwarf (WD) after the thermonuclear runaway drives a strong shock through the dense circumstellar gas produced by the red giant (RG) wind. This nova is a perfect real-time laboratory for studying physical processes as diverse as accretion, thermonuclear explosions, shock dynamics and particle acceleration; in many ways it is like a supernova remnant on fast forward. The experience of its previous outburst and of 2010 V407 Cyg (the only symbiotic nova that has ever occurred during the Fermi era), combined with our ongoing AMI-LA, MeerKAT and e-MERLIN monitoring, indicate that the EVN has the right combination of angular resolution and sensitivity to image the source and follow its evolution over the next few weeks/months. This will allow us to set independent and unique constraints on major outstanding problems, including the emission mechanisms, the physical processes at work, the presence and location of shock acceleration, the geometry of the system, and the density of the RG wind. In order to do this, we request five epochs between ~10 and ~60 days from the outburst, at both L- and C-band, for a total time request of 80 hours, part of which could be scheduled during already planned e-VLBI days or disk-recorded sessions. The inclusion of e-MERLIN outstations would also be important to map the di↵use emission, particularly at the latest epochs.