Context. The orbital angular momentum (OAM) of the photon is a property of light from astronomical objects that has not yet been measured. We propose a method of measuring the OAM spectrum of light from an extended natural source, the Sun. Relating the OAM spectrum of different solar areas to its structures could lead to a novel remote sensing

Visible and near-infrared spectra of transiting hot Jupiter planets have recently been observed, revealing some of the atmospheric constituents of their atmospheres. In the near future, it is probable that primary and secondary eclipse observations of Earth-like rocky planets will also be achieved. The characterization of Earth's transmission

High-resolution optical spectra of the ultra-luminous X-ray source (ULX) NGC 5408 X-1 show a broad component with a width of ~750 km s-1 in the He II and Hβ lines in addition to the narrow component observed in these lines and [O III]. Reanalysis of moderate-resolution spectra shows a similar broad component in the He II line. The broad component

Accurate model stellar fluxes are key for the analysis of observations of individual stars or stellar populations. Model spectra differ from real stellar spectra due to limitations of the input physical data and adopted simplifications, but can be empirically calibrated to maximize their resemblance to actual stellar spectra. We describe a least

We present the first results on the bremsstrahlung emission of photons accompanying ternary spontaneous fission of the 252Cf nucleus. We also compare our calculations on the basis of quantum model with preliminary experimental data and find a good agreement between theory and experiment for photon energies up to 500 keV, when the α-particle

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