3 research outputs found
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STRIDES: Automated uniform models for 30 quadruply imaged quasars
Gravitational time delays provide a powerful one-step measurement of H0, independent of all other probes. One key ingredient in time-delay cosmography are high-accuracy lens models. Those are currently expensive to obtain, both, in terms of computing and investigator time (105-106 CPU hours and ∼0.5-1 yr, respectively). Major improvements in modelling speed are therefore necessary to exploit the large number of lenses that are forecast to be discovered over the current decade. In order to bypass this roadblock, we develop an automated modelling pipeline and apply it to a sample of 31 lens systems, observed by the Hubble Space Telescope in multiple bands. Our automated pipeline can derive models for 30/31 lenses with few hours of human time and <100 CPU hours of computing time for a typical system. For each lens, we provide measurements of key parameters and predictions of magnification as well as time delays for the multiple images. We characterize the cosmography-readiness of our models using the stability of differences in the Fermat potential (proportional to time delay) with respect to modelling choices. We find that for 10/30 lenses, our models are cosmography or nearly cosmography grade (<3 per cent and 3-5 per cent variations). For 6/30 lenses, the models are close to cosmography grade (5-10 per cent). These results utilize informative priors and will need to be confirmed by further analysis. However, they are also likely to improve by extending the pipeline modelling sequence and options. In conclusion, we show that uniform cosmography grade modelling of large strong lens samples is within reach
First Wide Field-of-view X-Ray Observations by a Lobster-eye Focusing Telescope in Orbit
As a novel X-ray focusing technology, lobster-eye micropore optics (MPO) feature both a wide observing field of view and true imaging capability, promising sky monitoring with significantly improved sensitivity and spatial resolution in soft X-rays. Since first proposed by Angel, the optics have been extensively studied, developed and trialed over the past decades. In this Letter, we report on the first-light results from a flight experiment of the Lobster Eye Imager for Astronomy, a pathfinder of the wide-field X-ray telescope of the Einstein Probe mission. The piggyback imager, launched in 2022 July, has a mostly unvignetted field of view of 18.°6 × 18.°6. Its spatial resolution is in the range of 4′-7′ in FWHM and the focal spot effective area is 2-3 cm2, both showing only mild fluctuations across the field of view. We present images of the Galactic center region, Sco X-1, and the diffuse Cygnus Loop nebular taken in snapshot observations over 0.5-4 keV. These are truly wide-field X-ray images of celestial bodies observed, for the first time, by a focusing imaging telescope. Initial analyses of the in-flight data show excellent agreement between the observed images and the on-ground calibration and simulations. The instrument and its characterization are briefly described, as well as the flight experiment. The results provide a solid basis for the development of the present and proposed wide-field X-ray missions using lobster-eye MPO
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Final NOMAD results on muon-neutrino ---> tau-neutrino and electron-neutrino ---> tau-neutrino oscillations including a new search for tau-neutrino appearance using hadronic tau decays.
Results from the ?t appearance search in a neutrino beam using the full NOMAD data sample are reported. A new analysis unifies all the hadronic t decays, significantly improving the overall sensitivity of the experiment to oscillations. The “blind analysis” of all topologies yields no evidence for an oscillation signal. In the two-family oscillation scenario, this sets a 90% CL allowed region in the sin22?µt–?m2 plane which includes sin22?µt<3.3×10-4 at large ?m2 and ?m2< 0.7 eV2/c4 at sin22?µt=1. The corresponding contour in the ?e??t oscillation hypothesis results in sin22?et<1.5×10-2 at large ?m2 and ?m2<5.9 eV2/c4 at sin22?et=1. We also derive limits on effective couplings of the t lepton to ?µ or ?e