Search for gravitational waves from binary black hole inspirals in LIGO data

We report on a search for gravitational waves from binary black hole inspirals in the data from the second science run of the LIGO interferometers. The search focused on binary systems with component masses between 3 and $20M_{\odot }$. Optimally oriented binaries with distances up to 1 Mpc could be detected with efficiency of at least 90%. We found no events that could be identified as gravitational waves in the 385.6 hours of data that we searched.

Figure 1

Range (distance at which an optimally oriented inspiraling binary of given total mass would produce a signal-to-noise ratio of 8) of the LIGO interferometers during S2. The error bars are calculated from the fluctuations of the noise in the LIGO interferometers during S2.

Figure 2

Time domain plots of BCV waveforms for different values of ${\alpha }_F$. The top plot is for ${\alpha }_F=0$, the middle is for ${\alpha }_F=1$ and the bottom is for ${\alpha }_F=2$. For all three waveforms ${\psi }_0=150000{\mathrm{Hz}}^{5/3}$, ${\psi }_3=-1500{\mathrm{Hz}}^{2/3}$ and $f_{\mathrm{cut}}=500\mathrm{Hz}$. It can be seen that in the case of ${\alpha }_F=2$ the behavior is not that of a typical inspiral waveform.

Figure 3

The LLO and LHO SNRs of the accidental coincidences from the time-shifted triggers (crosses) and the triggers from the simulated signal injections (circles) are shown. The dashed lines show the equal false-alarm contours.

Figure 4

Expected accidental coincidences per S2 (triangles) with 1 standard deviation bars. The number of events in the S2 (circles) is overlayed.

Figure 5

The efficiency versus the LHO-effective distance for the different families of injected waveforms is shown. The dashed line represents the efficiency for PadéT1 injections, the dotted line represents the efficiency for standard post-Newtonian time-domain waveforms and the solid line represents the efficiency for effective-one-body waveforms. All injected waveforms were of second post-Newtonian order. Binomial error bars are shown.

Figure 6

The efficiency versus the injected total mass of all injected signals with LHO-effective distance between 1 and 3 Mpc for the different families of injected waveforms is shown. The dashed line represents the efficiency for PadéT1 injections, the dotted line represents the efficiency for standard post-Newtonian time-domain waveforms and the solid line represents the efficiency for effective-one-body waveforms. All injected waveforms were of second post-Newtonian order. Binomial error bars are shown.

Figure 7

The number of Milky Way equivalent galaxies (crosses) and the efficiency of the search (circles) as calculated by Eq. (19) versus the LHO-effective distance (in Mpc) are shown. The cumulative number of MWEGs $N_{\mathrm{G}}$ (diamonds) versus LHO-effective distance is overlayed. The horizontal axis has a logarithmic scale, in accordance with the uniform-$\log $ distance distribution of the injected BBH inspiral signals. No units are given for the vertical axis because it corresponds to three different quantities plotted against LHO-effective distance.