We present an up-to-date, comprehensive summary of the rates for all types of compact binary coalescence sources detectable by the initial and advanced versions of the ground-based gravitational-wave detectors LIGO and Virgo. Astrophysical estimates for compact-binary coalescence rates depend on a number of assumptions and unknown model parameters and are still uncertain. The most confident among these estimates are the rate predictions for coalescing binary neutron stars which are based on extrapolations from observed binary pulsars in our galaxy. These yield a likely coalescence rate of 100 Myr−1 per Milky Way Equivalent Galaxy (MWEG), although the rate could plausibly range from 1 Myr−1 MWEG−1 to 1000 Myr−1 MWEG−1 (Kalogera et al 2004 Astrophys. J. 601 L179; Kalogera et al 2004 Astrophys. J. 614 L137 (erratum)). We convert coalescence rates into detection rates based on data from the LIGO S5 and Virgo VSR2 science runs and projected sensitivities for our advanced detectors. Using the detector sensitivities derived from these data, we find a likely detection rate of 0.02 per year for Initial LIGO–Virgo interferometers, with a plausible range between 2 × 10−4 and 0.2 per year. The likely binary neutron–star detection rate for the Advanced LIGO–Virgo network increases to 40 events per year, with a range between 0.4 and 400 per year.

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We r e p o r t on measurements of quantum electrodynamic processes in an intense electromagnetic wave, where nonlinear e ects (both multiphoton and vacuum polarization) are prominent. Nonlinear Compton scattering and electronpositron pair production have been observed in collisions of 46.6 GeV and 49.1 GeV electrons of the Final Focus Test Beam at SLAC with terawatt pulses of 1053 nm and 527 nm wavelengths from a Nd:glass laser. Peak laser intensities of 0:5 10 18 W/cm 2 have been achieved, corresponding to a value of 0:4 for the parameter = eErms=m!0c, and to a value of 0:25 for the parameter e = E ? rms =Ecrit = eE ? rms h=m 2 c 3 , where E ? rms is the rms electric eld strength of the laser in the electron rest frame. We p r e s e n t data on the scattered electron spectra arising from nonlinear Compton scattering with up to four photons absorbed from the eld. A convolved spectrum of the forward high energy photons is also given. The observed positron production rate depends on the fth power of the laser intensity, as expected for a process where ve photons are absorbed from the eld. The positrons are interpreted as arising from the collision of a high-energy Compton scattered photon with the laser beam. The results are found to be in agreement with theoretical predictions.

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