152 research outputs found
Evolution of the fine-structure constant in runaway dilaton models
We study the detailed evolution of the fine-structure constant in
the string-inspired runaway dilaton class of models of Damour, Piazza and
Veneziano. We provide constraints on this scenario using the most recent
measurements and discuss ways to distinguish it from alternative
models for varying . For model parameters which saturate bounds from
current observations, the redshift drift signal can differ considerably from
that of the canonical CDM paradigm at high redshifts. Measurements of
this signal by the forthcoming European Extremely Large Telescope (E-ELT),
together with more sensitive measurements, will thus dramatically
constrain these scenarios.Comment: 11 pages, 4 figure
Probing dark energy beyond with CODEX
Precision measurements of nature's fundamental couplings and a first
measurement of the cosmological redshift drift are two of the key targets for
future high-resolution ultra-stable spectrographs such as CODEX. Being able to
do both gives CODEX a unique advantage, allowing it to probe dynamical dark
energy models (by measuring the behavior of their equation of state) deep in
the matter era and thereby testing classes of models that would otherwise be
difficult to distinguish from the standard CDM paradigm. We illustrate
this point with two simple case studies.Comment: 4 pages, 4 figures; submitted to Phys. Rev.
Dark Energy Survey Year 1 results: the lensing imprint of cosmic voids on the cosmic microwave background
Dark energy survey year 1 results: The lensing imprint of cosmic voids on the cosmic microwave background
Cosmic voids gravitationally lens the cosmic microwave background (CMB) radiation, resulting in a distinct imprint on degree scales. We use the simulated CMB lensing convergence map from the Marenostrum Institut de Ciencias de lâEspai (MICE) N-body simulation to calibrate our detection strategy for a given void definition and galaxy tracer density. We then identify cosmic voids in Dark Energy Survey (DES) Year 1 data and stack the Planck 2015 lensing convergence map on their locations, probing the consistency of simulated and observed void lensing signals. When fixing the shape of the stacked convergence profile to that calibrated from simulations, we find imprints at the 3Ď significance level for various analysis choices. The best measurement strategies based on the MICE calibration process yield S/N â 4 for DES Y1, and the best-fitting amplitude recovered from the data is consistent with expectations from MICE (A â 1). Given these results as well as the agreement between them and N-body simulations, we conclude that the previously reported excess integrated SachsâWolfe (ISW) signal associated with cosmic voids in DES Y1 has no counterpart in the Planck CMB lensing map.This work has made use of CosmoHub (see Carretero et al. 2017).
CosmoHub has been developed by the Port dâInformacio Cient ´ ´Ĺfica
(PIC), maintained through a collaboration of the Institut de F´Ĺsica
dâAltes Energies (IFAE) and the Centro de Investigaciones Energeticas, Medioambientales y Tecnol ´ ogicas (CIEMAT), and was ´
partially funded by the âPlan Estatal de Investigacion Cient ´ ´Ĺfica y
Tecnica y de Innovaci ´ onâ program of the Spanish government. ´
Funding for the DES Projects has been provided by the US Department of Energy, the US National Science Foundation, the Ministry
of Science and Education of Spain, the Science and Technology
Facilities Council of the United Kingdom, the Higher Education
Funding Council for England, the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign,
the Kavli Institute of Cosmological Physics at the University of
Chicago, the Center for Cosmology and Astro-Particle Physics at the
Ohio State University, the Mitchell Institute for Fundamental Physics
and Astronomy at Texas A&M University, Financiadora de Estudos
e Projetos, Fundac¸ao Carlos Chagas Filho de Amparo Ë a Pesquisa do `
Estado do Rio de Janeiro, Conselho Nacional de Desenvolvimento
Cient´Ĺfico e Tecnologico and the Minist ´ erio da Ci ´ encia, Tecnologia Ë
e Inovac¸ao, the Deutsche Forschungsgemeinschaft, and the Collab- Ë
orating Institutions in the Dark Energy Survey.
The Collaborating Institutions are Argonne National Laboratory,
the University of California at Santa Cruz, the University of
Cambridge, Centro de Investigaciones Energeticas, Medioambien- ´
tales y Tecnologicas-Madrid, the University of Chicago, Univer- ´
sity College London, the DES-Brazil Consortium, the University
of Edinburgh, the Eidgenossische Technische Hochschule (ETH) ¨
Zurich, Fermi National Accelerator Laboratory, the University of ¨
Illinois at Urbana-Champaign, the Institut de Ciencies de lâEspai `
(IEEC/CSIC), the Institut de F´Ĺsica dâAltes Energies, Lawrence
Berkeley National Laboratory, the Ludwig-Maximilians Universitat¨
Munchen and the associated Excellence Cluster Universe, the Uni- ¨
versity of Michigan, the National Optical Astronomy Observatory,
the University of Nottingham, The Ohio State University, the
University of Pennsylvania, the University of Portsmouth, SLAC
National Accelerator Laboratory, Stanford University, the University
of Sussex, Texas A&M University, and the OzDES Membership
Consortium.
This paper is based in part on observations at Cerro Tololo InterAmerican Observatory, National Optical Astronomy Observatory,
which is operated by the Association of Universities for Research in
Astronomy (AURA) under a cooperative agreement with the National
Science Foundation.
The DES data management system is supported by the National Science Foundation under Grant Numbers AST-1138766
and AST-1536171. The DES participants from Spanish institutions are partially supported by MINECO under grants AYA2015-
71825, ESP2015-66861, FPA2015-68048, SEV-2016-0588, SEV2016-0597, and MDM-2015-0509, some of which include ERDF
funds from the European Union. IFAE is partially funded by the
CERCA program of the Generalitat de Catalunya.
Research leading to these results has received funding from the
European Research Council under the European Unionâs Seventh
Framework Program (FP7/2007-2013) including ERC grant agreements 240672, 291329, 306478, and 615929. We acknowledge
support from the Brazilian Instituto Nacional de Cienciae Tecnologia Ë
(INCT) e-Universe (CNPq grant 465376/2014-2).
This paper has been authored by Fermi Research Alliance, LLC
under Contract No. DE-AC02-07CH11359 with the US Department
of Energy, Office of Science, Office of High Energy Physics.
PV acknowledges the support from the grant MIUR PRIN 2015
âCosmology and Fundamental Physics: illuminating the Dark Universe with Euclidâ.
AK has been supported by a Juan de la Cierva fellowship from
MINECO with project number IJC2018-037730-I. Funding for this
project was also available in part through SEV-2015-0548 and
AYA2017-89891-P.
This project has also received funding from the European Unionâs
Horizon 2020 research and innovation programme under the Marie
SkĹodowska-Curie grant agreement No. 754558.Peer reviewe
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