A single fast radio burst localized to a massive galaxy at cosmological distance

Fast radio bursts (FRBs) are brief radio emissions from distant astronomical sources. Some are known to repeat, but most are single bursts. Nonrepeating FRB observations have had insufficient positional accuracy to localize them to an individual host galaxy. We report the interferometric localization of the single-pulse FRB 180924 to a position 4 kiloparsecs from the center of a luminous galaxy at redshift 0.3214. The burst has not been observed to repeat. The properties of the burst and its host are markedly different from those of the only other accurately localized FRB source. The integrated electron column density along the line of sight closely matches models of the intergalactic medium, indicating that some FRBs are clean probes of the baryonic component of the cosmic web

The Spectral Properties of the Bright Fast Radio Burst Population

We examine the spectra of 23 fast radio bursts (FRBs) detected in a fly's-eye survey with the Australian SKA Pathfinder, including those of three bursts not previously reported. The mean spectral index of α = -1.5 -0.3+0.2 (Fv ∞ v α) is close to that of the Galactic pulsar population. The sample is dominated by bursts exhibiting a large degree of spectral modulation: 17 exhibit fine-scale spectral modulation with an rms exceeding 50% of the mean, with decorrelation bandwidths (half-maximum) ranging from ≈1 to 49 MHz. Most decorrelation bandwidths are an order of magnitude lower than the ≳30 MHz expected of Galactic interstellar scintillation at the Galactic latitude of the survey, |b| = 50° ± 5°. However, these bandwidths are consistent with the ∼v 4 scaling expected of diffractive scintillation when compared against the spectral structure observed in bright UTMOST FRBs detected at 843 MHz. A test of the amplitude distribution of the spectral fluctuations reveals only 12 bursts consistent at better than a 5% confidence level with the prediction of 100%-modulated diffractive scintillation. Five of six FRBs with a signal-tonoise ratio exceeding 20 are only consistent with this prediction at less than 1% confidence. Nonetheless, there is weak evidence (92%-94% confidence) of an anti-correlation between the amplitude of the spectral modulation and dispersion measure (DM), which suggests that it originates as a propagation effect. This effect is corroborated by the smoothness of the higher-DM Parkes FRBs, and could arise due to quenching of diffractive scintillation (e.g., in the interstellar medium of the host galaxy) by angular broadening in the intergalactic medium

Technology and Care for Patients with Chronic Conditions: The Chronic Care Model as a Framework for the Integration of ICT

Part 3: Section 2: Sustainable and Responsible InnovationInternational audienceWorldwide, healthcare systems are considered unsustainable due to an increase in demand for care and an associated rise in healthcare costs. Ageing of societies and the growth of populations with chronic conditions are making a paradigm shift in western healthcare systems necessary. The Chronic Care Model (CCM) provides a framework for healthcare change, including a prominent role for the community and patients’ self-management. Information and communication technology (ICT) is indispensable to accomplish the model’s objectives. The role of ICT in the provision of care is discussed as an opportunity to facilitate the application of the CCM and improve healthcare in general

WALLABY pilot survey: Public release of H <scp>i</scp> data for almost 600 galaxies from phase 1 of ASKAP pilot observations

International audienceAbstract We present WALLABY pilot data release 1, the first public release of H i pilot survey data from the Wide-field ASKAP L-band Legacy All-sky Blind Survey (WALLABY) on the Australian Square Kilometre Array Pathfinder. Phase 1 of the WALLABY pilot survey targeted three $60\,\mathrm{deg}^{2}$ regions on the sky in the direction of the Hydra and Norma galaxy clusters and the NGC 4636 galaxy group, covering the redshift range of $z \lesssim 0.08$ . The source catalogue, images and spectra of nearly 600 extragalactic H i detections and kinematic models for 109 spatially resolved galaxies are available. As the pilot survey targeted regions containing nearby group and cluster environments, the median redshift of the sample of $z \approx 0.014$ is relatively low compared to the full WALLABY survey. The median galaxy H i mass is $2.3 \times 10^{9}\,{\rm M}_{{\odot}}$ . The target noise level of $1.6\,\mathrm{mJy}$ per 30′′ beam and $18.5\,\mathrm{kHz}$ channel translates into a $5 \sigma$ H i mass sensitivity for point sources of about $5.2 \times 10^{8} \, (D_{\rm L} / \mathrm{100\,Mpc})^{2} \, {\rm M}_{{\odot}}$ across 50 spectral channels ( ${\approx} 200\,\mathrm{km \, s}^{-1}$ ) and a $5 \sigma$ H i column density sensitivity of about $8.6 \times 10^{19} \, (1 + z)^{4}\,\mathrm{cm}^{-2}$ across 5 channels ( ${\approx} 20\,\mathrm{km \, s}^{-1}$ ) for emission filling the 30′′ beam. As expected for a pilot survey, several technical issues and artefacts are still affecting the data quality. Most notably, there are systematic flux errors of up to several 10% caused by uncertainties about the exact size and shape of each of the primary beams as well as the presence of sidelobes due to the finite deconvolution threshold. In addition, artefacts such as residual continuum emission and bandpass ripples have affected some of the data. The pilot survey has been highly successful in uncovering such technical problems, most of which are expected to be addressed and rectified before the start of the full WALLABY survey.</jats:p

Australian square kilometre array pathfinder : I. system description

In this paper, we describe the system design and capabilities of the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope at the conclusion of its construction project and commencement of science operations. ASKAP is one of the first radio telescopes to deploy phased array feed (PAF) technology on a large scale, giving it an instantaneous field of view that covers 31 deg(2) at 800MHz. As a two-dimensional array of 36x12 m antennas, with baselines ranging from 22 m to 6 km, ASKAP also has excellent snapshot imaging capability and 10 arcsec resolution. This, combined with 288 MHz of instantaneous bandwidth and a unique third axis of rotation on each antenna, gives ASKAP the capability to create high dynamic range images of large sky areas very quickly. It is an excellent telescope for surveys between 700 and 1800MHz and is expected to facilitate great advances in our understanding of galaxy formation, cosmology, and radio transients while opening new parameter space for discovery of the unknown