MODELING X-RAY BINARY EVOLUTION IN NORMAL GALAXIES: INSIGHTS FROM SINGS

摘要: We present the largest-scale comparison to date between observed extragalactic X-ray binary (XRB) populations and theoretical models of their production. construct observational luminosity functions (oXLFs) using Chandra observations 12 late-type galaxies from Spitzer Infrared Nearby Galaxy Survey (SINGS). For each galaxy, we obtain XLFs (tXLFs) by combining XRB synthetic models, constructed with population synthesis code StarTrack, star formation histories (SFHs). identify highest-likelihood both for individual globally, averaged over full galaxy sample. Individual tXLFs successfully reproduce about half oXLFs, but some are unable find underlying source populations, indicating that SFHs metallicities not well matched and/or modeling requires calibration on larger samples. Given these limitations, best consistent a product common envelope ejection efficiency central donor concentration ≃ 0.1, 50% uniform – “twins” initial mass-ratio distribution. discuss constituent subpopulations according donor, accretor stellar characteristics. The galaxy-wide due low-mass high-mass XRBs, estimated via our global model tXLF, follows general trend expected LX - rate mass relations Lehmer et al. (2010). Our also in agreement evolution XRBs cosmic time redshift.