Second Einstein Telescope mock science challenge: Detection of the gravitational-wave stochastic background from compact binary coalescences

We present the results of the search for an astrophysical gravitational-wave stochastic background during the second Einstein Telescope mock data and science challenge. Assuming that the loudest sources can be detected individually and removed from the data, we show that the residual background can be recovered with an accuracy of 1% with the standard cross-correlation statistic, after correction of a systematic bias due to the anisotropy of the sources.

Figure 1

The sensitivity curve ET-B (dashed red line) used for the first ET MDSC and and ET-D (continuous red line) used for the second ET MDSC. Advanced LIGO and Virgo noise curves are also shown for comparison.

Figure 2

${\mathrm{\Omega }}_{\text{gw}}$ calculated from the list of CBC sources present in the first (continuous lines) and the second (dashed lines) data sets of ET MDC2, for NS-NS (blue triangles), NS-BH (green squares), BH-BH (red crosses) and the total (black line with no markers).

Figure 3

Detection efficiency as a function of the polar angle $\theta$ (measured from the zenith direction) for redshifts between 0–10, for NS-NS sources with masses $1.4+1.4{\mathrm{M}}_{\odot }$. The efficiency as a function of the inclination angle $\iota$ has a similar behavior. At a redshift $z=0$ the efficiency is 1 for all the values of $\theta$ and $\iota$ while at the horizon distance of $z\sim 3.8$ only face-on sources located at the zenith or at the nadir are detected. The white area indicates there is no detection.

Figure 4

Contribution to the SNR of frequencies $<f$, for ET-D (ET MDC2) and ET-B (ET MDC1) [34].