1,949 research outputs found
The cosmological impact of future constraints on from gravitational-wave standard sirens
Gravitational-wave standard sirens present a novel approach for the
determination of the Hubble constant. After the recent spectacular confirmation
of the method thanks to GW170817 and its optical counterpart, additional
standard siren measurements from future gravitational-wave sources are expected
to constrain the Hubble constant to high accuracy. At the same time, improved
constraints are expected from observations of cosmic microwave background (CMB)
polarization and from baryon acoustic oscillations (BAO) surveys. We explore
the role of future standard siren constraints on in light of expected
CMB+BAO data. Considering a -parameters cosmological model, in which
curvature, the dark energy equation of state, and the Hubble constant are
unbounded by CMB observations, we find that a combination of future CMB+BAO
data will constrain the Hubble parameter to . Further extending
the parameter space to a time-varying dark energy equation of state, we find
that future CMB+BAO constraints on are relaxed to . These
accuracies are within reach of future standard siren measurements from the
Hanford-Livingston-Virgo and the Hanford-Livingston-Virgo-Japan-India networks
of interferometers, showing the cosmological relevance of these sources. If
future gravitational-wave standard siren measurements reach on , as
expected, they would significantly improve future CMB+BAO constraints on
curvature and on the dark energy equation of state by up to a factor .
We also show that the inclusion of constraints from gravitational-wave
standard sirens could result in a reduction of the dark energy figure-of-merit
(i.e., the cosmological parameter volume) by up to a factor of .Comment: 14 pages, 5 figures, included discussion on FoM, new references, in
press on PR
Neutrino mass bounds in the era of tension cosmology
The measurements of Cosmic Microwave Background anisotropies made by the
Planck satellite provide extremely tight upper bounds on the total neutrino
mass scale ( at C.L.). However, as recently
discussed in the literature, Planck data show anomalies that could affect this
result. Here we provide new constraints on neutrino masses using the recent and
complementary CMB measurements from the Atacama Cosmology Telescope DR4 and the
South Polar Telescope SPT-3G experiments. We found that both the ACT-DR4 and
SPT-3G data, when combined with WMAP, mildly suggest a neutrino mass with
eV and eV
at C.L, respectively. Moreover, when CMB lensing from the Planck
experiment is included, the ACT-DR4 data now indicates a neutrino mass above
the two standard deviations, with eV at
, while WMAP+SPT-3G provides a weak upper limit of
eV at C.L.. Interestingly, these results are consistent with the Planck
CMB+Lensing constraint of eV at
C.L. when variation in the parameter are considered. We also
show that these indications are still present after the inclusion of BAO or
SN-Ia data in extended cosmologies that are usually considered to solve the
so-called Hubble tension. A combination of ACT-DR4, WMAP, BAO and constraints
on the Hubble constant from the SH0ES collaboration gives eV at C.L. in extended cosmologies. We
conclude that a total neutrino mass above the eV limit still provides an
excellent fit to several cosmological data and that future data must be
considered before safely ruling it out.Comment: 6 pages, 3 Figure
Active biopolymer coating based on sodium caseinate: Physical characterization and antioxidant activity
The objective of this work was to investigate the effect of sodium caseinate concentration on physical-chemical properties of coating solutions and films obtained by casting as a starting point for the development of an active coating for minimally processed fruits or vegetables. Sodium caseinate solutions at different concentrations (4%, 8%, 10%, 12%, 14%) were used as a coating system. The coating viscosity and desorption kinetic were characterized. Minimally processed fennels were coated by dipping and the liquid and dry coating thickness were estimated by assessing the amount of coating on fennel during draining as a function of solution properties (concentration and viscosity). Film obtained by casting were also characterized in terms of equilibrium moisture content, color, and water vapor permeability. The potential of using the sodium caseinate solution to obtain active coating was investigated by adding gallic acid or rosemary oil to sodium caseinate solution at 4%. The antioxidant capacity of the coating was evaluated by DPPH test. Results show that sodium caseinate solutions follow a Newtonian behavior in the range of concentration investigated and the viscosity increased as solids concentration increased, following a power law. The drying rate was in the range 0.0063-0.00107 mgH2O•mgsolids-1•min-1•m-2 as a function of sodium caseinate concentration. The average liquid and dry coating thickness on fennels were in the range 20-70 and 0.7-6.4 μm, respectively. The water vapor permeability slightly decreased as the solid concentration increased. Active coating showed good antioxidant properties
Lensing impact on cosmic relics and tensions
Cosmological bounds on neutrinos and additional hypothetical light thermal relics, such as QCD axions, are currently among the most restrictive ones. These limits mainly rely on cosmic microwave background temperature anisotropies. Nonetheless, one of the largest cosmological signatures of thermal relics is that on gravitational lensing, due to their free-streaming behavior before their nonrelativistic period. We investigate late-time only hot-relic mass constraints, primarily based on recently released lensing data from the Atacama Cosmology Telescope, both alone and in combination with lensing data from the Planck satellite. Additionally, we consider other local probes, such as baryon acoustic oscillations measurements, shear-shear, galaxy-galaxy, and galaxy-shear correlation functions from the dark energy survey, and distance moduli measurements from Type-Ia Supernovae. The tightest bounds we find are mν<0.43 eV and ma<1.1 eV, both at 95% CL Interestingly, these limits are still much stronger than those found on e.g., laboratory neutrino mass searches, reassessing the robustness of the extraction of thermal relic properties via cosmological observations. In addition, when considering lensing-only data, the significance of the Hubble constant tension is considerably reduced, while the clustering parameter σ8 controversy is completely absent
Special Issue on modified gravity approaches to the tensions of ΛCDM: goals and highlights
The standard cosmological model, known as ΛCDM, has been remarkably successful in providing a coherent and predictive framework for understanding the Universe’s evolution, its large-scale structure, and cosmic microwave background (CMB) radiation [...
Exploring cosmic origins with CORE : Cosmological parameters
We forecast the main cosmological parameter constraints achievable with the CORE space mission which is dedicated to mapping the polarisation of the Cosmic Microwave Background (CMB). CORE was recently submitted in response to ESA's fifth call for medium-sized mission proposals (M5). Here we report the results from our pre-submission study of the impact of various instrumental options, in particular the telescope size and sensitivity level, and review the great, transformative potential of the mission as proposed. Specifically, we assess the impact on a broad range of fundamental parameters of our Universe as a function of the expected CMB characteristics, with other papers in the series focusing on controlling astrophysical and instrumental residual systematics. In this paper, we assume that only a few central CORE frequency channels are usable for our purpose, all others being devoted to the cleaning of astrophysical contaminants. On the theoretical side, we assume ACDM as our general framework and quantify the improvement provided by CORE over the current constraints from the Planck 2015 release. We also study the joint sensitivity of CORE and of future Baryon Acoustic Oscillation and Large Scale Structure experiments like DESI and Euclid. Specific constraints on the physics of inflation are presented in another paper of the series. In addition to the six parameters of the base ACDM, which describe the matter content of a spatially flat universe with adiabatic and scalar primordial fluctuations from inflation, we derive the precision achievable on parameters like those describing curvature, neutrino physics, extra light relics, primordial helium abundance, dark matter annihilation, recombination physics, variation of fundamental constants, dark energy, modified gravity, reionization and cosmic birefringence. In addition to assessing the improvement on the precision of individual parameters, we also forecast the post-CORE overall reduction of the allowed parameter space with figures of merit for various models increasing by as much as similar to 10(7) as compared to Planck 2015, and 10(5) with respect to Planck 2015 + future BAO measurements.Peer reviewe
Exploring the growth index γL: Insights from different CMB dataset combinations and approaches
In this study we investigate the growth index γL, which characterizes the growth of linear matter perturbations, while analysing different cosmological datasets. We compare the approaches implemented by two different patches of the cosmological solver CAMB: MGCAMB and CAMB_GAMMAPRIME_GROWTH. In our analysis we uncover a deviation of the growth index from its expected ΛCDM value of 0.55 when utilizing the Planck dataset, both in the MGCAMB case and in the CAMB_GAMMAPRIME_GROWTH case, but in opposite directions. This deviation is accompanied by a change in the direction of correlations with derived cosmological parameters. However, the incorporation of cosmic microwave background lensing data helps reconcile γL with its Λ-cold dark matter value in both cases. Conversely, the alternative ground-based telescopes Atacama Cosmology Telescope and South Pole Telescope consistently yield growth index values in agreement with γL ¼ 0.55. We conclude that the presence of the Alens problem in the Planck
dataset contributes to the observed deviations, underscoring the importance of additional datasets in resolving these discrepancies
- …