A bright millisecond radio burst of extragalactic origin

Pulsar surveys offer one of the few opportunities to monitor even a small fraction (~0.00001) of the radio sky for impulsive burst-like events with millisecond durations. In analysis of archival survey data, we have discovered a 30-Jy dispersed burst of duration <5 ms located three degrees from the Small Magellanic Cloud. The burst properties argue against a physical association with our Galaxy or the Small Magellanic Cloud. Current models for the free electron content in the Universe imply a distance to the burst of <1 Gpc No further bursts are seen in 90-hr of additional observations, implying that it was a singular event such as a supernova or coalescence of relativistic objects. Hundreds of similar events could occur every day and act as insightful cosmological probes.Comment: 18 pages, 4 figures. Accepted by Science. Published electronically via Science Express on September 27, 200

Triangulation of gravitational wave sources with a network of detectors

There is significant benefit to be gained by pursuing multi-messenger astronomy with gravitational wave and electromagnetic observations. In order to undertake electromagnetic follow-ups of gravitational wave signals, it will be necessary to accurately localize them in the sky. Since gravitational wave detectors are not inherently pointing instruments, localization will occur primarily through triangulation with a network of detectors. We investigate the expected timing accuracy for observed signals and the consequences for localization. In addition, we discuss the effect of systematic uncertainties in the waveform and calibration of the instruments on the localization of sources. We provide illustrative results of timing and localization accuracy as well as systematic effects for coalescing binary waveforms.Comment: 20 pages, 5 figure

Rural Water Policy in Africa and Asia

Universal delivery of improved drinking water services in rural Africa and Asia has been an enduring policy challenge for decades. Whilst drinking water coverage has generally improved, only one in five countries below 95% coverage in 2015 is currently on track to achieve basic drinking water services for all by 2030. We identify and evaluate three periods of rural water policy in Africa and Asia between 1980 and 2030 to (i) identify four pillars of rural water policy design, (ii) consider how they have adapted over time, and (iii) propose priorities for progress. We argue for an increase in investments in designing and testing emerging institutional models for rural water services to evaluate the trade‐offs in performance across institutional, financial and operational dimensions. Stronger empirical evidence will allow policy and planning to balance and negotiate short‐term political goals with long‐term sector sustainability for the benefit of the poor