161. Dark Matter science in the era of LSST : Astro2020 science white paperKeith Bechtol, Alex Drlica-Wagner, Kevork N. Abazajian, Muntazir Abidi, Susmita Adhikari, Yacine Ali-Haïmoud, James Annis, Behzad Ansarinejad, Christopher Eckner, Gabrijela Zaharijas, 2019, project documentation (preliminary design, working design) Keywords: cosmology, nongalactic astrophysics, high energy astrophysical phenomena, high energy physics, experiments Published in RUNG: 03.05.2022; Views: 1417; Downloads: 36 Link to full text This document has many files! More... |
162. Probing the fundamental nature of Dark Matter with the Large Synoptic Survey Telescope : v1.1Alex Drlica-Wagner, Yao-Yuan Mao, Susmita Adhikari, Robert Armstrong, Arka Banerjee, Nilanjan Banik, Keith Bechtol, Simeon Bird, Christopher Eckner, Gabrijela Zaharijas, 2019, project documentation (preliminary design, working design) Keywords: dark matter, high energy physics, astrophysical observations, cosmological observations, Large Synoptic Survey Telescope (LSST) Published in RUNG: 03.05.2022; Views: 1353; Downloads: 42 Link to full text This document has many files! More... |
163. Catalog of long-term transient sources in the first 10 yr of Fermi-LAT dataL. Baldini, J. Ballet, D. Bastieri, J. Becerra Gonzalez, R. Bellazzini, A. Berretta, E. Bissaldi, R. D. Blandford, E. D. Bloom, Gabrijela Zaharijas, 2021, original scientific article Keywords: high energy astrophysics, active galactic nuclei, gamma-ray bursts, solar flares, solar gamma-ray emission Published in RUNG: 17.02.2022; Views: 1632; Downloads: 40 Link to full text This document has many files! More... |
164. Testing effects of Lorentz invariance violation in the propagation of astroparticles with the Pierre Auger ObservatoryP. Abreu, Andrej Filipčič, Jon Paul Lundquist, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2022, original scientific article Keywords: cosmic ray experiments, ultra high energy, cosmic rays, physics of the early universe, Pierre Auger Observatory, Lorentz invariance violation effects Published in RUNG: 18.01.2022; Views: 1528; Downloads: 37 Link to full text This document has many files! More... |
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167. Application of machine learning techniques for cosmic ray event classification and implementation of a real-time ultra-high energy photon search with the surface detector of the Pierre Auger Observatory : dissertationLukas Zehrer, 2021, doctoral dissertation Abstract: Despite their discovery already more than a century ago, Cosmic Rays (CRs) still did not divulge all their properties yet. Theories about the origin of ultra-high energy (UHE, > 10^18 eV) CRs predict accompanying primary photons. The existence of UHE photons can be investigated with the world’s largest ground-based experiment for detection of CR-induced extensive air showers (EAS), the Pierre Auger Observatory, which offers an unprecedented exposure to rare UHE cosmic particles.
The discovery of photons in the UHE regime would open a new observational window to the Universe, improve our understanding of the origin of CRs, and potentially uncloak new physics beyond the standard model.
The novelty of the presented work is the development of a "real-time" photon candidate event stream to a global network of observatories, the Astrophysical Multimessenger Observatory Network (AMON). The stream classifies CR events observed by the Auger surface detector (SD) array as regards their probability to be photon nominees, by feeding to advanced machine learning (ML) methods observational air shower parameters of individual CR events combined in a multivariate analysis (MVA).
The described straightforward classification procedure further increases the Pierre Auger Observatory’s endeavour to contribute to the global effort of multi-messenger (MM) studies of the highest energy astrophysical phenomena, by supplying AMON partner observatories the possibility to follow-up detected UHE events, live or in their archival data. Keywords: astroparticle physics, ultra-high energy cosmic rays, ultra-high energy photons, extensive air showers, Pierre Auger Observatory, multi-messenger, AMON, machine learning, multivariate analysis, dissertations Published in RUNG: 27.10.2021; Views: 2704; Downloads: 147 Link to full text This document has many files! More... |
168. Experimental bounds on sterile-active neutrino mixing anglesMihael Petač, 2015, master's thesis Abstract: Despite the success of the Standard Model in the last few decades, we know it is not complete. There is strong motivation for assuming the existence of additional heavy neutral leptons, which can account for active neutrino masses and possibly also have cosmological implications. In this work I consider the Standard Model with two neutral lepton singlets (sterile neutrinos) with degenerated masses in the range 20MeV - 2GeV. The constraints on the active-sterile neutrino mixing angles are evaluated based on recent neutrino oscillations data. Using these constraints the bounds from accelerator experiments are reanalyzed for the case of the considered model. Finally, the results are compared with cosmological constraints coming from Big Bang nucleosynthesis and the nMSM resonant leptogenesis. Keywords: Sterile neutrinos, Neutrino mixing, See-saw, High-Energy Physics - Phenomenology, High-Energy Physics - Experiments Published in RUNG: 01.10.2021; Views: 1636; Downloads: 46 Full text (1,93 MB) |
169. Testing the predictions of axisymmetric distribution functions of galactic dark matter with hydrodynamical simulationsMihael Petač, Julien Lavalle, Arturo Núñez-Castiñeyra, Emmanuel Nezri, 2021, original scientific article Abstract: Signal predictions for galactic dark matter (DM) searches often rely on assumptions regarding the DM phase-space distribution function (DF) in halos. This applies to both particle (e.g. p-wave suppressed or Sommerfeld-enhanced annihilation, scattering off atoms, etc.) and macroscopic DM candidates (e.g. microlensing of primordial black holes). As experiments and observations improve in precision, better assessing theoretical uncertainties becomes pressing in the prospect of deriving reliable constraints on DM candidates or trustworthy hints for detection. Most reliable predictions of DFs in halos are based on solving the steady-state collisionless Boltzmann equation (e.g. Eddington-like inversions, action-angle methods, etc.) consistently with observational constraints. One can do so starting from maximal symmetries and a minimal set of degrees of freedom, and then increasing complexity. Key issues are then whether adding complexity, which is computationally costy, improves predictions, and if so where to stop. Clues can be obtained by making predictions for zoomed-in hydrodynamical cosmological simulations in which one can access the true (coarse-grained) phase-space information. Here, we test an axisymmetric extension of the Eddington inversion to predict the full DM DF from its density profile and the total gravitational potential of the system. This permits to go beyond spherical symmetry, and is a priori well suited for spiral galaxies. We show that axisymmetry does not necessarily improve over spherical symmetry because the (observationally unconstrained) angular momentum of the DM halo is not generically aligned with the baryonic one. Theoretical errors are similar to those of the Eddington inversion though, at the 10-20% level for velocity-dependent predictions related to particle DM searches in spiral galaxies. We extensively describe the approach and comment on the results. Keywords: galaxy dynamics, dark matter experiments, dark matter simulations, dark matter theory, cosmology, nongalactic astrophysics, astrophysics of galaxies, high energy physics Published in RUNG: 01.10.2021; Views: 1882; Downloads: 64 Link to full text This document has many files! More... |
170. Two-integral distribution functions in axisymmetric galaxies: Implications for dark matter searchesMihael Petač, Piero Ullio, 2019, original scientific article Abstract: We address the problem of reconstructing the phase-space distribution function for an extended collisionless system, with known density profile and in equilibrium within an axisymmetric gravitational potential. Assuming that it depends on only two integrals of motion, namely the energy and the component of the angular momentum along the axis of symmetry Lz , there is a one-to-one correspondence between the density profile and the component of the distribution function that is even in Lz, as well as between the weighted azimuthal velocity profile and the odd component. This inversion procedure was originally proposed by Lynden-Bell and later refined in its numerical implementation by Hunter and Qian; after overcoming a technical difficulty, we apply it here for the first time in presence of a strongly flattened component, as a novel approach of extracting the phase-space distribution function for dark matter particles in the halo of spiral galaxies. We compare results obtained for realistic axisymmetric models to those in the spherical symmetric limit as assumed in previous analyses, showing the rather severe shortcomings in the latter. We then apply the scheme to the Milky Way and discuss the implications for the direct dark matter searches. In particular, we reinterpret the null results of the Xenon1T experiment for spin-(in)dependent interactions and make predictions for the annual modulation of the signal for a set of axisymmetric models, including a self-consistently defined corotating halo. Keywords: dark matter, astrophysics of galaxies, high energy physics, phenomenology Published in RUNG: 01.10.2021; Views: 1737; Downloads: 0 This document has many files! More... |