Lensing magnification: gravitational waves from coalescing stellar-mass binary black holes

ABSTRACT Gravitational waves (GWs) may be magnified or de-magnified due to lensing. This phenomenon will bias the distance estimation based on matched filtering technique. Via multi-sphere ray-tracing technique, we study GW magnification effect and selection with particular attention stellar-mass binary black holes. We find that, for observed luminosity $\lesssim 3\, \mathrm{Gpc}$, which is aLIGO/Virgo observational horizon limit, average keeps as unity, namely unbiased estimation, relative uncertainty $\sigma (\hat{d})/\hat{d}\simeq 0.5{{\ \rm per\ cent}}\sim 1{{\ cent}}$. Beyond this horizon, can not ignored, scatters (\hat{d})/\hat{d} = 15{{\ Furthermore, forecast these numbers Einstein Telescope (ET). that closely unity 90\, \mathrm{Gpc}$. The error lensing ET about \simeq 10{{\ cent}}$ $\gtrsim 25\, Unlike case, sizable effect. It purely comes from unavoidably accumulated magnification. Moreover, investigated effects of orientation angle BH mass distribution models. found results are strongly dependent two components.