Speaker
Description
Type-I X-ray bursts in neutron star (NS) low mass X-ray binaries are highly energetic events with the power to dynamically change the accretion flow. Studying such dynamical effects is a powerful new method that could shed light on accretion disk physics, coronae and the origin of relativistic jets. Correctly modelling time resolved X-ray spectra during these bursts allows for measurements of NS radii, which can be used to constrain the NS equation of state. Observations of Type-I X-ray bursts have shown that the emission from the accretion environment often increases during thermonuclear bursts. Although previously attributed to enhanced accretion due to Poynting-Robertson drag, recent theoretical work predicts that disk heating plays a more dominant role in the increase of persistent emission. This implies that the disk component changes in spectral shape during the burst; a phenomenon often not taken into account when fitting models to observed data. Using semi-analytical calculations, I model X-ray bursts of various luminosities irradiating standard Shakura-Sunyaev disks with different persistent accretion rates. The models predict an increase in emission from the accretion flow by a factor of $\sim 10-100$ during the burst, dominated by the heated disk rather than enhanced accretion. After the burst, a dip in emission is expected due to a carved out inner disk. Verifying these results by novel observational tests could improve spectral models of Type-I X-ray bursts.
| Talk category | NOVA Network 3 |
|---|---|
| PhD relevance | 1st |
