Early multiwavelength analysis of the recurrent nova V745 Sco

TL;DR

This study investigates the early shock evolution and particle acceleration in the 2014 recurrent nova V745 Sco through multiwavelength observations, revealing similarities with RS Oph and insights into gamma-ray emission mechanisms.

Contribution

It provides a comprehensive multiwavelength analysis of V745 Sco's outburst, highlighting the early shock dynamics and potential particle acceleration processes in recurrent novae.

Findings

Striking similarities with RS Oph in plasma properties.

Skipping of the adiabatic phase in shock evolution.

Hints of particle acceleration in nova ejecta.

Abstract

In recent years, several nova explosions have been detected by Fermi/LAT at E>100 MeV, mainly early after the explosion and for a short period of time. The first evidence of particle acceleration in novae was found in the 2006 eruption of RS Oph, to explain the faster than expected deceleration of the blast wave. As a consequence, emission of high-energy gamma-rays mainly from neutral pion decay and inverse Compton scattering is expected. We aim to understand the early shock evolution, when acceleration of particles can take place, in nova explosions. To achieve this goal, we perform a multiwavelength study of the 2014 outburst of V745 Sco, a symbiotic recurrent nova similar to RS Oph. The analysis of early Swift/XRT observations, simultaneous to the tentative Fermi detection, is combined with Chandra and NuStar data, to get a global picture of the nova ejecta and the red giant wind evolution. Early radio and IR data are also compiled, providing information about the forward shock velocity and its magnetic field. The comparison with the plasma properties of RS Oph shows striking similarities, such as the skipping of the adiabatic phase occurring in supernova remnants, a hint of particle acceleration. The multiwavelength study of V745 Sco provides new insights into the evolution of the hot plasma in novae and its interaction with the circumstellar material, a powerful tool to understand the nature of the high-energy gamma-ray emission from symbiotic recurrent novae.