6 research outputs found

    The Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope: I. Overview of the instrument and its capabilities

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    We provide an overview of the design and capabilities of the near-infrared spectrograph (NIRSpec) onboard the James Webb Space Telescope. NIRSpec is designed to be capable of carrying out low-resolution (R ⁣=30 ⁣330R\!=30\!-330) prism spectroscopy over the wavelength range 0.65.3 ⁣ μ0.6-5.3\!~\mum and higher resolution (R ⁣=500 ⁣1340R\!=500\!-1340 or R ⁣=1320 ⁣3600R\!=1320\!-3600) grating spectroscopy over 0.75.2 ⁣ μ0.7-5.2\!~\mum, both in single-object mode employing any one of five fixed slits, or a 3.1×\times3.2 arcsec2^2 integral field unit, or in multiobject mode employing a novel programmable micro-shutter device covering a 3.6×\times3.4~arcmin2^2 field of view. The all-reflective optical chain of NIRSpec and the performance of its different components are described, and some of the trade-offs made in designing the instrument are touched upon. The faint-end spectrophotometric sensitivity expected of NIRSpec, as well as its dependency on the energetic particle environment that its two detector arrays are likely to be subjected to in orbit are also discussed

    Longitudinal patterns of financial products ownership: a latent growth mixture approach

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    The main goal of this study is to analyze the dynamic process of financial product ownership under the assumption of heterogeneous growth by latent growth mixture models. Using panel data from a survey conducted by the Bank of Italy, we conclude that the trajectory of Italian households in terms of financial product ownership in the period 2000 to 2006 is homogeneous. Moreover, the process allowed the identification of an outlier trajectory and the obtainment of robust estimates for the population parameters
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