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.
A photocatalyst- and additive-free visible-light-induced
6π-photocyclization
of ortho-biaryl-appended β-ketoesters has been
developed. Upon irradiation with visible light, substrates undergo
6-endo-trig cyclization/1,5-H shift to 9,10-dihydrophenanthren-9-ols
with high efficiency and selectivity. The reaction proceeds via conrotatory ring closure followed by a suprafacial 1,5-hydrogen
shift leading to the observed single trans-fused
products. Preliminary mechanistic studies reveal the feasibility of
both 1,5-H shift and intersystem crossing of the diradical intermediate.
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