Advanced search in
Research products
arrow_drop_down
Searching FieldsTerms
Any field
arrow_drop_down
includes
arrow_drop_down
Include:
257 Research products, page 1 of 26

  • Publications
  • Other research products
  • 2013-2022
  • Conference object
  • GB
  • AT
  • IL
  • HAL AMU

10
arrow_drop_down
Relevance
arrow_drop_down
  • Publication . Article . Conference object . Preprint . 2018
    Open Access English
    Authors: 
    G. Stratta; Riccardo Ciolfi; Lorenzo Amati; Enrico Bozzo; Giancarlo Ghirlanda; Elisabetta Maiorano; Luciano Nicastro; Andrea Rossi; Serena Vinciguerra; F. Frontera; +48 more
    Publisher: HAL CCSD
    Countries: France, Netherlands, Italy, Poland, Netherlands
    Project: EC | COSMOLOGICAL CANDLES (626267)

    The recent discovery of the electromagnetic counterpart of the gravitational wave source GW170817, has demonstrated the huge informative power of multi-messenger observations. During the next decade the nascent field of multi-messenger astronomy will mature significantly. Around 2030, third generation gravitational wave detectors will be roughly ten times more sensitive than the current ones. At the same time, neutrino detectors currently upgrading to multi km^3 telescopes, will include a 10 km^3 facility in the Southern hemisphere that is expected to be operational around 2030. In this review, we describe the most promising high frequency gravitational wave and neutrino sources that will be detected in the next two decades. In this context, we show the important role of the Transient High Energy Sky and Early Universe Surveyor (THESEUS), a mission concept proposed to ESA by a large international collaboration in response to the call for the Cosmic Vision Programme M5 missions. THESEUS aims at providing a substantial advancement in early Universe science as well as playing a fundamental role in multi-messenger and time-domain astrophysics, operating in strong synergy with future gravitational wave and neutrino detectors as well as major ground- and space-based telescopes. This review is an extension of the THESEUS white paper (Amati et al. 2017), also in light of the discovery of GW170817/GRB170817A that was announced on October 16th, 2017. 25 pages, 13 figures, accepted to Advances in Space Research with minor revisions. Details on the THESEUS instrumentation, science case and expected performances can also be found in Amati et al. 2017 (arXiv:1710.04638) and in the presentations of the THESEUS Workshop 2017 (http://www.isdc.unige.ch/theseus/workshop2017-programme.html). v2 few typos corrected

  • Publication . Part of book or chapter of book . Preprint . Article . 2020
    Open Access English
    Authors: 
    Florian Bridoux; Maximilien Gadouleau; Guillaume Theyssier;
    Publisher: HAL CCSD
    Country: France

    Automata networks are mappings of the form \(f: Q^Z \rightarrow Q^Z\), where Q is a finite alphabet and Z is a set of entities; they generalise Cellular Automata and Boolean networks. An update schedule dictates when each entity updates its state according to its local function \(f_i: Q^Z \rightarrow Q\). One major question is to study the behaviour of a given automata networks under different update schedules. In this paper, we study automata networks that are invariant under many different update schedules. This gives rise to two definitions, locally commutative and globally commutative networks. We investigate the relation between commutativity and different forms of locality of update functions; one main conclusion is that globally commutative networks have strong dynamical properties, while locally commutative networks are much less constrained. We also give a complete classification of all globally commutative Boolean networks.

  • Publication . Conference object . Article . Preprint . 2016 . Embargo End Date: 01 Jan 2017
    Open Access
    Authors: 
    Pierre Dubath; Nikolaos Apostolakos; Andrea Bonchi; Andrey Belikov; Massimo Brescia; Stefano Cavuoti; Peter Capak; Jean Coupon; Christophe Dabin; H. Degaudenzi; +30 more
    Publisher: arXiv
    Countries: Italy, France, Netherlands

    Euclid is a Europe-led cosmology space mission dedicated to a visible and near infrared survey of the entire extra-galactic sky. Its purpose is to deepen our knowledge of the dark content of our Universe. After an overview of the Euclid mission and science, this contribution describes how the community is getting organized to face the data analysis challenges, both in software development and in operational data processing matters. It ends with a more specific account of some of the main contributions of the Swiss Science Data Center (SDC-CH). Comment: 10 pages, 4 figures, IAU Symposium 325 on Astroinformatics

  • Publication . Preprint . Article . Conference object . 2016
    Open Access English
    Authors: 
    Chris Evans; M. Puech; Myriam Rodrigues; Beatriz Barbuy; Jean-Gabriel Cuby; Gavin Dalton; Ewan Fitzsimons; Francois Hammer; P. Jagourel; Lex Kaper; +2 more
    Countries: United Kingdom, France, Netherlands, United Kingdom, France

    Building on the comprehensive White Paper on the scientific case for multi-object spectroscopy on the European ELT, we present the top-level instrument requirements that are being used in the Phase A design study of the MOSAIC concept. The assembled cases span the full range of E-ELT science and generally require either 'high multiplex' or 'high definition' observations to best exploit the excellent sensitivity and spatial performance of the telescope. We highlight some of the science studies that are now being used in trade-off studies to inform the capabilities of MOSAIC and its technical design. Comment: 12 pages, in Ground-based and Airborne Instrumentation for Astronomy VI, 2016, Proc. SPIE 9908, 9J

  • Publication . Conference object . Article . Preprint . 2018
    Open Access English
    Authors: 
    Raouf Boucekkine; Fabien Prieur; Chrysovalantis Vasilakis; Benteng Zou;
    Publisher: HAL CCSD
    Country: France
    Project: ANR | GREEN-Econ (ANR-16-CE03-0005), ANR | AMSE (EUR) (ANR-17-EURE-0020)

    We provide an analysis of institutional dynamics under uncertainty by means of a stochastic differential game of lobbying with two players (conservatives vs liberals) and three main ingredients. The first one is uncertainty inherent in the institutional process itself. The second considers resource windfalls volatility impact on economic and institutional outcomes. Last but not least, the resource windfall level matters in the relative bargaining power of the players. We compute a unique closed-loop equilibrium with linear feedbacks. We show that the legislative state converges to an invariant distribution. Even more importantly, we demonstrate that the most likely asymptotic legislative state is favorable to the liberals. However, the more volatile resource windfalls, the less liberal is the most likely asymptotic state. Finally, we assess the latter prediction on a database covering 91 countries over the period 1973-2005. We focus on financial liberalization policies. We find that as the resources revenues volatility increases, the financial liberalization index goes down. We also find that this property remains robust across different specifications and sample distinctions.

  • Publication . Conference object . Article . Preprint . 2014
    Open Access English
    Authors: 
    Glenn Merlet; Thomas Nowak; Hans Schneider; Sergei Sergeev;
    Publisher: HAL CCSD
    Country: France
    Project: UKRI | Perron-Frobenius theory a... (EP/J00829X/1)

    We study sequences of optimal walks of a growing length, in weighted digraphs, or equivalently, sequences of entries of max-algebraic matrix powers with growing exponents. It is known that these sequences are eventually periodic when the digraphs are strongly connected. The transient of such periodicity depends, in general, both on the size of digraph and on the magnitude of the weights. In this paper, we show that some bounds on the indices of periodicity of (unweighted) digraphs, such as the bounds of Wielandt, Dulmage-Mendelsohn, Schwarz, Kim and Gregory-Kirkland-Pullman, apply to the weights of optimal walks when one of their ends is a critical node. Comment: 17 pages, 3 figures

  • Open Access English
    Authors: 
    Muhammad Alhroob; M. Battistin; S. Berry; A. Bitadze; P. Bonneau; G. Boyd; O. Crespo-Lopez; C. Degeorge; Cecile Deterre; B. Di Girolamo; +20 more
    Publisher: HAL CCSD
    Countries: Germany, France

    Custom ultrasonic instruments have been developed for simultaneous monitoring of binary gas mixture and flow in the ATLAS Inner Detector. Sound transit times are measured in opposite directions in flowing gas. Flow rate and sound velocity are respectively calculated from their difference and average. Gas composition is evaluated in real-time by comparison with a sound velocity/composition database, based on the direct dependence of sound velocity on component concentrations in a mixture at known temperature and pressure. Five devices are integrated into the ATLAS Detector Control System. Three instruments monitor coolant leaks into N$_2$ envelopes of the silicon microstrip and Pixel detectors. Resolutions better than ±2 × 10$^{−5}$ and ± 2 × 10$^{−4}$ are seen for C$_3$F$_8$ and CO$_2$ leak concentrations in N$_2$ respectively. A fourth instrument detects sub-percent levels of air ingress into the C 3 F 8 condenser of the new thermosiphon coolant recirculator. Following extensive studies a fifth instrument was built as an angled sound path flowmeter to measure the high returning C$_3$F$_8$ vapour flux (∼1.2kgs$^{−1}$) . A precision of <2.3% FS for flows up to 10ms$^{−1}$ was demonstrated. These instruments have many potential applications where continuous binary gas composition measurement is required, including hydrocarbon and anaesthetic gas mixtures. 14th Vienna Conference on Instrumentation, Vienna, Austria, 15 Feb 2016 - 19 Feb 2016; Nuclear instruments & methods in physics research / A 845, 273 - 277 (2017). doi:10.1016/j.nima.2016.04.104 Published by North-Holland Publ. Co., Amsterdam

  • Open Access English
    Authors: 
    Mayet, F.; Adam, R.; Ade, P.; André, P.; Arnaud, M.; Aussel, H.; Bartalucci, I.; Beelen, A.; Benoît, A.; Bideaud, A.; +32 more
    Publisher: HAL CCSD
    Country: France
    Project: EC | ORISTARS (291294), ANR | FOCUS (ANR-11-LABX-0013)

    The development of precision cosmology with clusters of galaxies requires high-angular resolution Sunyaev-Zel'dovich (SZ) observations. As for now, arcmin resolution SZ observations (e.g. SPT, ACT and Planck) only allowed detailed studies of the intra cluster medium for low redshift clusters (z<0.2). With both a wide field of view (6.5 arcmin) and a high angular resolution (17.7 and 11.2 arcsec at 150 and 260 GHz), the NIKA2 camera installed at the IRAM 30-m telescope (Pico Veleta, Spain), will bring valuable information in the field of SZ imaging of clusters of galaxies. The NIKA2 SZ observation program will allow us to observe a large sample of clusters (50) at redshifts between 0.4 and 0.9. As a pilot study for NIKA2, several clusters of galaxies have been observed with the pathfinder, NIKA, at the IRAM 30-m telescope to cover the various configurations and observation conditions expected for NIKA2. Proceedings of the 29th Rencontres de Blois (Particle Physics and Cosmology), May 28th - June 2nd 2017, Blois (France)

  • Publication . Article . Conference object . Preprint . 2018
    Open Access English
    Authors: 
    Simon L. Morris; Francois Hammer; P. Jagourel; Chris Evans; Mathieu Puech; Gavin Dalton; Myriam Rodrigues; Ruben Sanchez-Janssen; Ewan Fitzsimons; Beatriz Barbuy; +44 more
    Publisher: HAL CCSD
    Countries: France, France, Netherlands, France, France, United Kingdom, United Kingdom, Spain, Netherlands

    When combined with the huge collecting area of the ELT, MOSAIC will be the most effective and flexible Multi-Object Spectrograph (MOS) facility in the world, having both a high multiplex and a multi-Integral Field Unit (Multi-IFU) capability. It will be the fastest way to spectroscopically follow-up the faintest sources, probing the reionisation epoch, as well as evaluating the evolution of the dwarf mass function over most of the age of the Universe. MOSAIC will be world-leading in generating an inventory of both the dark matter (from realistic rotation curves with MOAO fed NIR IFUs) and the cool to warm-hot gas phases in z=3.5 galactic haloes (with visible wavelenth IFUs). Galactic archaeology and the first massive black holes are additional targets for which MOSAIC will also be revolutionary. MOAO and accurate sky subtraction with fibres have now been demonstrated on sky, removing all low Technical Readiness Level (TRL) items from the instrument. A prompt implementation of MOSAIC is feasible, and indeed could increase the robustness and reduce risk on the ELT, since it does not require diffraction limited adaptive optics performance. Science programmes and survey strategies are currently being investigated by the Consortium, which is also hoping to welcome a few new partners in the next two years. Comment: 6 pages, 3 figures, Submitted to SPIE Proceedings, AS18

  • Closed Access English
    Authors: 
    L. Abou-Khalil; G. Salloum-Abou-Jaoude; Guillaume Reinhart; C. Pickmann; Gerhard Zimmermann; Y. Houltz; J. Li; O. Janson; Henri Nguyen-Thi;
    Publisher: HAL CCSD
    Country: France

    International audience; In the framework of an ESA-MAP project entitled XRMON, directional solidification experiments of Al – 20 wt% Cu with in situ and real-time X-ray radiography were carried out during Parabolic Flight campaigns. Parabolic flights offer successions of periods with different gravity levels, allowing the investigation of the impact of gravity level variations on the solidification microstructure formation. Directional solidifications of refined Al – 20 wt% Cu alloy were investigated in a dedicated apparatus for a wide range of cooling rates and a constant temperature gradient. X-ray radiography was successfully used to observe the microstructure evolution following the variations of gravity level. During the columnar growth of the refined alloy a sharp increase of gravity level provoked the sudden nucleation of numerous grains ahead of the front. The most potent explanation of this effect is the variation of the liquid undercooling ahead of solid/liquid interface due to the changes of hydrostatic pressure in the melt.

Send a message
How can we help?
We usually respond in a few hours.