Multi-epoch X-ray burst modelling: MCMC with large grids of 1D simulations

摘要: Type-I X-ray bursts are recurring thermonuclear explosions on the surface of accreting neutron stars. Matching observed to computational models can help constrain system properties, such as star mass and radius, crustal heating rates, accreted fuel composition, but systematic parameter studies date have been limited. We apply Markov chain Monte Carlo methods 1D burst for first time, obtain estimations `Clocked Burster', GS 1826$-$238, by fitting multiple epochs simultaneously. explore parameters which often held constant, including mass, rate, hydrogen composition. To improve efficiency, we precompute a grid 3840 KEPLER - largest set simulations interpolating over model grid, rapidly sample predictions. estimates CNO metallicity $Z_\mathrm{CNO} = 0.010^{+0.005}_{-0.004}$, fraction $X_0 0.74^{+0.02}_{-0.03}$, distance $d \sqrt{\xi_\mathrm{b}} 6.5^{+0.4}_{-0.6}\, \mathrm{kpc}$, inclination $i {69^{+2}_{-3}}^{\circ}$.