A catalogue of the voids in the IRAS 1.2- Jy survey

Using the void finder algorithm we have compiled a catalogue of voids in the IRAS 1.2-Jy sample. The positions of the voids correspond well to the underdense regions seen in the IRAS smoothed density map. However, since in our analysis no smoothing is used, all structures appear much sharper: walls are not smeared and the voids are not artificially reduced by them. Therefore the current method based on the point distribution of galaxies is better suited to determining the diameter of voids in the galaxy distribution. We have identified 24 voids, covering more than 30 per cent of the volume considered. By comparing the results with equivalent random catalogues we have determined that 12 voids are significant at a 0.95 confidence level, having an average diameter of 40 ± 6 h−1 Mpc. Our results serve not only for charting the cosmography of the nearby Universe, but also to give support to the results recently obtained with the SSRS2 sample, suggesting a void-filled Universe. Moreover, our results indicate that the voids detected have a similar scale, demonstrating that both optically selected and IRAS-selected galaxies delineate the same large-scale structures.