Open Issues on the Synthesis of Evolved Stellar Populations at Ultraviolet Wavelengths

In this paper we briefly review three topics that have motivated our (and others') investigations in recent years within the context of evolutionary population synthesis techniques. These are: The origin of the FUV up-turn in elliptical galaxies, the age-metallicity degeneracy, and the study of the mid-UV rest-frame spectra of distant red galaxies. We summarize some of our results and present a very preliminary application of a UV grid of theoretical spectra in the analysis of integrated properties of aged stellar populations. At the end, we concisely suggest how these topics can be tackled once the World Space Observatory enters into operation in the midst of this decade.Comment: 8 pages, 4 figures, accepted for publication in Astrophysics & Space Science, UV Universe special issu

Theory for the FCC-ee: Report on the 11th FCC-ee Workshop Theory and Experiments

The FCC at CERN, a proposed 100-km circular facility with several colliders in succession, culminates with a 100 TeV proton-proton collider. It offers a vast new domain of exploration in particle physics, with orders of magnitude advances in terms of Precision, Sensitivity and Energy. The implementation plan foresees, as a first step, an Electroweak Factory electron-positron collider. This high luminosity facility, operating between 90 and 365 GeV centre-of-mass energy, will study the heavy particles of the Standard Model, Z, W, Higgs, and top with unprecedented accuracy. The Electroweak Factory $e^+e^-$ collider constitutes a real challenge to the theory and to precision calculations, triggering the need for the development of new mathematical methods and software tools. A first workshop in 2018 had focused on the first FCC-ee stage, the Tera-Z, and confronted the theoretical status of precision Standard Model calculations on the Z-boson resonance to the experimental demands. The second workshop in January 2019, which is reported here, extended the scope to the next stages, with the production of W-bosons (FCC-ee-W), the Higgs boson (FCC-ee-H) and top quarks (FCC-ee-tt). In particular, the theoretical precision in the determination of the crucial input parameters, alpha_QED, alpha_QCD, M_W, m_t at the level of FCC-ee requirements is thoroughly discussed. The requirements on Standard Model theory calculations were spelled out, so as to meet the demanding accuracy of the FCC-ee experimental potential. The discussion of innovative methods and tools for multi-loop calculations was deepened. Furthermore, phenomenological analyses beyond the Standard Model were discussed, in particular the effective theory approaches. The reports of 2018 and 2019 serve as white papers of the workshop results and subsequent developments.The Future Circular Collider (FCC) at CERN, a proposed100km circular facility with several collidersin succession, culminates in a100TeV proton–proton collider. It offers a vast new domain of explorationin particle physics, with orders-of-magnitude advances in terms of precision, sensitivity, and energy.The implementation plan published in 2018 foresees, as a first step, an electroweak factory electron–positron collider. This high-luminosity facility, operating at centre-of-mass energies between 90 and365GeV, will study the heavy particles of the Standard Model (SM), Z, W, and Higgs bosons, andtop quarks with unprecedented accuracy. The physics programme offers great discovery potential:(i) through precision measurements, (ii) through sensitive searches for symmetry violations, forbidden,or extremely rare decays, and (iii) through the search for direct observation of new particles withextremely small couplings. The electroweak factorye+e−collider constitutes a real challenge to thetheory and to precision calculations, triggering the need for the development of new mathematicalmethods and software tools. A first workshop in 2018 focused on the first FCC-ee stage, the Tera-Z, andconfronted the theoretical status of precision Standard Model calculations on the Z boson resonanceto the experimental demands.The second workshop, in January 2019, extended the scope to the next stages, with the pro-duction of W bosons (FCC-ee-W), the Higgs boson (FCC-ee-H), and top quarks (FCC-ee-tt). In par-ticular, the theoretical precision in the determination of the crucial input parameters,αQED,αQCD,MW, andmt, at the level of FCC-ee requirements was thoroughly discussed. The requirements onStandard Model theory calculations were spelt out, so as to meet the demanding accuracy of theFCC-ee experimental potential. The discussion of innovative methods and tools for multiloop calcu-lations was deepened. Furthermore, phenomenological analyses beyond the Standard Model were dis-cussed, including effective theory approaches. The reports of 2018 and 2019 serve as white papers ofthe workshop results and subsequent developments

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4 m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5 m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 yr, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit. © 2023. The Author(s). Published by IOP Publishing Ltd on behalf of the Astronomical Society of the Pacific (ASP). All rights reserved.Open access articleThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]