The Impact of Photospheric Expansion Bursts on the Neutron Star Accretion Flow – Thesis Proposal –

Neutron stars in low-mass X-ray binaries (LMXBs) accrete matter from a donor star. The emission of the neutron star and the accretion environment is detectable in the X-ray band (section 2.1). Due to unstable nuclear burning, neutron stars can undergo Type I X-ray bursts and emit vasts amount of radiation (section 2.2). Observations as well as simulations showed that this radiation impacts the accretion flow environment, both its structure as well as its emission (section 2.2.1, 3). If the burst luminosity is high enough, radiation pressure can lift off the neutron star photosphere and remove material from the neutron star (section 2.3). These photospheric radius expansion (PRE) bursts have been used to estimate the distance to neutron stars and to constrain their mass and radii (section 2.3.1). However, these studies often neglect the effect of the burst on the accretion environment and its potential impact on the emission. For my thesis, I therefore propose to simulate the accretion environment impacted by a PRE burst with the code Cosmos++ (section 4).