Accuracy of mass and radius determination of neutron star in X-ray bursters from simulated LOFT spectrum

Agnieszka Majczyna, Agata Różańska, Jerzy Madej and Mirosław Należyty

Large Area Detector (LAD) on the board of LOFT satellite, due to the large surface area, will allow us to obtain spectra of hot neutron star with very good energy resolution at 1 second integration time. Such spectra could be fitted by model spectra to obtain mass and radius determination. We present simulated spectra of type I X-ray bursters. Since these objects have very high temperatures, we could observe them in the LOFT energy band. To simulate our synthetic spectra we used the response matrix prepared by the LAD detector team. Then simulated spectrum was analysed to estimate accuracy of the determination of the neutron star parameters, mass and radius. Accurate values of both parameters allow us to constrain the equation of state of neutron star matter. Errors of mass end radius determination, which were defined here as the half of 3σ confidence contours, equal δM=0.12 M_sun (7%) and δR=1.68 km (14%).

Proceedings of the Polish Astronomical Society, vol. 1, 124-127 (2014)

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