[Normal Galaxies, Clusters of Galaxies -- Oral ]
Modeling X-ray binary populations in elliptical galaxies.
Tassos Fragos, Northwestern University
Kalogera, V. (Northwestern University), Fabbiano, G. (Harvard-Smithsonian Center for Astrophysics)
X-ray binaries are unique astrophysical laboratories as they
carry information about many complex physical processes such as star
formation, compact object formation, and evolution of interacting binary
systems. Motivated by deep Chandra observations of extra-galactic
populations of X-ray binaries, I will present theoretical models for the
formation and evolution of populations of low-mass X-ray binaries
(LMXBs) in the two elliptical galaxies NGC 3379 and NGC 4278. The models
are calculated with the recently updated StarTrack code, assuming only a
primordial galactic field LMXB population. StarTrack is an advanced
population synthesis code that has been tested and calibrated using
detailed binary star calculations and incorporates all the important
physical processes of binary evolution. The simulations are targeted to
modeling and understanding the origin of the X-ray luminosity functions
(XLFs) of point sources in these galaxies. For the first time we explore
the population XLF in luminosities below 10E37 erg/s, as probed by the
most recent observational results. Furthermore, I will present a physically
motivated and self-consistent prescription for the modeling of transient
neutron star LMXB properties, such as duty cycle, outburst duration and
recurrence time, and compare the model transient LMXB population to the
Chandra X-ray survey of the two ellipticals, which revealed several
transient sources. Finally, I will briefly talk about an ongoing project
towards developing a new advanced computational tool for the study of
X-ray binary populations formed in both galactic fields and dense
stellar clusters.