Michal Dominik, Krzysztof Belczynski, Christopher Fryer, Daniel Holz, Emanuele Berti, Tomasz Bulik, Ilya Mandel, Richard O'Shaughnessy
The development of gravitational wave observatories (Advanced LIGO/Virgo,
Einstein Telescope) is proceeding apace, and the direct detection of
gravitational waves should be imminent. The last decade of observational and
theoretical developments in stellar and binary evolution provides us with
improvements to the predictions from populations synthesis models. Among the
most important revisions in the formation and evolution of double compact
objects are: updated wind mass loss rates (allowing for stellar mass black
holes up to 80 Msun), a realistic treatment of the common envelope phase (that
can affect merger rates by 2--3 orders of magnitude), and a qualitatively new
neutron star/black hole mass distribution (consistent with the observed "mass
gap"). We present a parameter study with these major physical updates included,
focusing on the most important factors that set the DCO merger rates. A few of
our more interesting findings are: the binding energy of the envelope and our
description of natal kicks from supernovae play an important role in
determining the formation and merger rate of DCOs. Also, models incorporating
delayed (SASI) supernovae do not agree with the observed NS/BH "mass gap", in
accordance with our previous work. And, finally, we find enhanced rates for
BH-BH mergers as compared to previous estimates, with an expectation of ~100
such mergers per year in Advanced LIGO/Virgo detectors (although this rate is
sensitive to factors, such as the natal kick distribution). This is the first
in a series of three papers. The second paper will study the merger rates of
double compact objects as a function of cosmological redshift, star formation
rate, and metallicity. In the third paper we will present the detection rates
for future gravitational wave observatories, using up-to-date signal waveforms
and sensitivity curves. (abridged)
View original:
http://arxiv.org/abs/1202.4901
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