Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of binary black hole coalescences confidently observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include the effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that have already been identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total source-frame mass M > 70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz emitted gravitational-wave frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place a conservative upper limit for the merger rate density of high-mass binaries with eccentricities 0 < e ≤ 0.3 at 16.9 Gpc−3 yr−1 at the 90% confidence level

Between the Book and the Lamp – Interiors of Bureaucracy and the Materiality of Colonial Power

J.W. Breyer, the young South African military administration's first game warden in Namibia, was based at Namutoni on the south-eastern margin of the Etosha pan. Breyer died a lonely death and a meticulous inventory was rendered of Breyer's estate. Viktor Franke, the German commander in south-western Africa, and Cocky Hahn, the second South African commissioner of native affairs stationed at Ondangwa, similarly left a visual record of their intimate surroundings. An itinerary of their material worlds and hence of colonialism in Namibia is here revealed using photographs and other evidence, highlighting some of the complexities of the cultural practices of colonial administration and policing in southern Africa