Simon Christoph Schuler

We present a detailed investigation of different excitonic states weakly confined in single GaAs/AlGaAs quantum dots obtained by the Al droplet-etching method. For our analysis we make use of temperature-, polarization- and magnetic field-dependent $\mu$-photoluminescence measurements, which allow us to identify different excited states of the quantum dot system. Besides that, we present a comprehensive analysis of g-factors and diamagnetic coefficients of charged and neutral excitonic states in Voigt and Faraday configuration. Supported by theoretical calculations by the Configuration interaction method, we show that the widely used single-particle Zeeman Hamiltonian cannot be used to extract reliable values of the g-factors of the constituent particles from excitonic transition measurements.

The traditional solution foreseen for the realization of very large x-ray mirror modules (diameters above 1 m) is the partition of the optics in azimuth and radial modules (like Silicon Pore Optics in Athena). Even if this approach solves the initial problem of the procurement and the handling of very large substrates, it moves the difficulties in the second phase, when thousands of segments have to be assembled without degrading their optical performances. On the contrary, a simpler large mirror module design could correspond to less than a few hundred thin (2 mm to 4 mm for mirror shells between 0.4 m and 3 m diameter) monolithic shells. This configuration keeps both the advantage of the design simplicity and of the high-resolution capability, achievable through the direct polishing approach. Moreover, it guarantees an impressive gain in the polishing time. A technology development road map for this approach is funded in Italy by ASI and led by INAF-OAB. In this paper, we present the advancements obtained in the development of the different phases of the process and in the procurement of new substrates.

The remarkable scientific return and legacy of LSST, in the era that it will define, will not only be realized in the breakthrough science that will be achieved with catalog data. This Big Data survey will shape the way the entire astronomical community advances -- or fails to embrace -- new ways of approaching astronomical research and data. In this white paper, we address the NRC template questions 4,5,6,8 and 9, with a focus on the unique challenges for smaller, and often under-resourced, institutions, including institutions dedicated to underserved minority populations, in the efficient and effective use of LSST data products to maximize LSST's scientific return.

An X-ray Observatory, with superb imaging capabilities and with large throughput, has been recognised as a strategic missions in the Astro2020 decadal survey. The traditional solution foreseen for the realisation of very large x-ray mirror modules (diameters above 1 m) is the partition of the optics in azimuthal and radial modules (like Silicon Pore Optics in Athena). Even if this approach solves the initial problem of the procurement and the handling of very large substrates, it moves the difficulties in the second phase, when thousands of segments have to be assembled without degrading their optical performances. On the contrary, a simpler large mirror module design could correspond to less than a few hundred thin monolithic shells. As an example, the complete opto-mechanical design, compliant with the Lynx mass budget and based on fused silica, foresees that the shell thickness ranges between 2 and 4 mm (for mirror shells between 0.4 and 3 m diameter). The conceptual design of such an mirror module could be refined for smaller scale mission, keeping both the advantage of the design simplicity and of the high-resolution capability, achievable through the direct polishing approach. A technology development roadmap for this approach is funded in Italy by ASI and led by INAF-OAB. In this paper, we present the advancements obtained in the development of the different phases of the process and in the realisation of two new single-reflection shells (SR shells), almost representative of the final optical configuration foreseen for the mirror assembly. The first shell will be used to prove the figuring process in a lab-mount, built upon elements of the previous supporting structure concept. The second shell will be hosted in an upgraded lab-mount structure, which guarantees better performances (frequencies, gravity and thermo-elastic response) and which is suitable to test the transfer of the shell to a spider-like configuration.