Speaker
Description
The identification of compact object type as either black hole (BH) or neutron star (NS) is fundamental to understanding their formation and evolution, and provides critical constraints concerning the final stages of supernovae. At the population level, X-ray binaries are linked to a number of host galaxy parameters, inform the expected rate of gravitational wave detections, and may have contributed to heating of the IGM prior to the epoch of reionization. To date, time-domain determination of compact object type remains a relatively untapped tool outside of the Milky Way Galaxy, although it has shown great promise through, e.g., detection of Quasi Periodic Oscillations (QPOs) in extragalactic black holes and discovery of pulsations in Ultraluminous X-ray (ULX) sources. Timing studies of X-ray sources (such as pulsations and thermonuclear bursts) offer a reliable means of confirming the nature of compact objects like NSs, whereas spectral modeling often suffers from degeneracies. Measurements of QPOs, pulsations, and bursts in extragalactic populations (rather than individual bright sources) will lead to a revolution in the study of NS and BH population demographics, linking source phenomena to accretion and galaxy parameters (e.g., star formation, metallicity). NewAthena’s WFI features instrumental design characteristics that will make such timing studies of extragalactic X-ray binary (XRB) populations possible. Its wide field of view (40’ x 40’) can capture either significant fractions or the full extent of galaxies in single observations. The large collecting area collects sufficient photons to enable timing. The PSF is sufficient to spatially resolve populations down to scientifically interesting flux limits, and the WFI detector has good timing resolution for the determination of key XRB timing behaviors. In this talk, we discuss the WFI’s capabilities for performing such measurements in a variety of galaxy environments and to greater distances, showcasing its aptitude for timing studies of extragalactic XRB populations.
