The Hot and Energetic Universe: End points of stellar evolution

TL;DR

This paper discusses how Athena+ will revolutionize our understanding of stellar remnants like white dwarfs, neutron stars, and black holes by enabling detailed studies of their emission, accretion, spin, winds, and fundamental properties.

Contribution

It introduces Athena+'s capabilities to significantly advance the study of extreme matter in stellar remnants, including spin measurements, wind analysis, and neutron star equation of state constraints.

Findings

Enhanced measurement of stellar black hole spins.

Detailed analysis of disc wind properties and launching mechanisms.

Multiple constraints on neutron star mass-radius relation.

Abstract

White dwarfs, neutron stars and stellar mass black holes are key laboratories to study matter in most extreme conditions of gravity and magnetic field. The unprecedented effective area of Athena+ will allow us to advance our understanding of emission mechanisms and accretion physics over a wide range of mass accretion rates, starting from lower and sub-luminous quiescent X-ray binaries up to super-Eddington ultra-luminous sources. Athena+ will measure stellar black hole spins in a much higher number of binaries than achievable now, opening the possibility to study how spin varies with black hole history. The high throughput and energy resolution of the X-IFU will be instrumental in establishing how disc wind properties depend on accretion state, in determining wind launching mechanism and in quantifying the impact of the wind induced mass loss on binary evolution and environment. Triggers and high quality optical and radio data originating from large wide field contemporaneous instruments will provide essential complementary information on jet launching mechanisms and on the physics of rotation powered pulsars, for instance. In addition, Athena+ will furnish multiple, independent measurements of the neutron star mass/radius relation in a wide range of environments and conditions so as to constrain the debated equation of state.