A. Melchiorri
A5016781401- Cosmology and Gravitation Theories
- Galaxies: Formation, Evolution, Phenomena
- Dark Matter and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Astrophysics and Star Formation Studies
- Particle physics theoretical and experimental studies
- Black Holes and Theoretical Physics
- Geophysics and Gravity Measurements
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Neutrino Physics Research
- Relativity and Gravitational Theory
- Scientific Research and Discoveries
- Solar and Space Plasma Dynamics
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Atmospheric Ozone and Climate
- Superconducting and THz Device Technology
- Advanced Differential Geometry Research
- Radioactive Decay and Measurement Techniques
- Pulsars and Gravitational Waves Research
- Calibration and Measurement Techniques
- Astronomical Observations and Instrumentation
- History and Developments in Astronomy
Sapienza University of Rome
2016-2025
Istituto Nazionale di Fisica Nucleare, Sezione di Roma I
2014-2025
Istituto Nazionale di Fisica Nucleare
2004-2025
University of California, Berkeley
2018
Centre National de la Recherche Scientifique
2018
Aix-Marseille Université
2018
University of Illinois Urbana-Champaign
2018
Université Paris Cité
2018
Délégation Paris 7
2018
Sorbonne Paris Cité
2018
Abstract The simplest ΛCDM model provides a good fit to large span of cosmological data but harbors areas phenomenology and ignorance. With the improvement number accuracy observations, discrepancies among key parameters have emerged. most statistically significant tension is 4 σ 6 disagreement between predictions Hubble constant, H 0 , made by early time probes in concert with ‘vanilla’ model, late time, model-independent determinations from local measurements distances redshifts. high...
This paper presents a measurement of the angular power spectrum cosmic microwave background from l = 75 to 1025 (~10' 24) combined analysis four 150 GHz channels in BOOMERANG experiment. The contains multiple peaks and minima, as predicted by standard adiabatic inflationary models which primordial plasma undergoes acoustic oscillations. These results, concert with other types cosmological measurements theoretical models, significantly constrain values Ωtot, Ωbh2, Ωch2, ns.
Recent results from BOOMERANG-98 and MAXIMA-1, taken together with COBE DMR, provide consistent high signal-to-noise measurements of the cosmic microwave background power spectrum at spherical harmonic multipole bands over 2<l less similar to 800. Analysis combined data yields 68% (95%) confidence limits on total density, Omega(tot) approximately 1.11+/-0.07 (+0.13)(-0.12), baryon Omega(b)h(2) 0.032(+0.005)(-0.004) (+0.009)(-0.008), scalar spectral tilt, n(s) 1.01(+0.09)(-0.07)...
By combining data from seven cosmic microwave background experiments (including the latest WMAP results) with Hubble parameter measurement space telescope and luminosity measurements of type Ia supernovae, we demonstrate bounds on dark energy equation state ${w}_{Q}$ to be $\ensuremath{-}1.45<{w}_{Q}<\ensuremath{-}0.74$ at 95% confidence level. Although our limit is improved respect previous analyses, cosmological do not rule out possibility that Q less than $\ensuremath{-}1.$ We present a...
Euclid is a space-based survey mission from the European Space Agency designed to understand origin of Universe's accelerating expansion. It will use cosmological probes investigate nature dark energy, matter and gravity by tracking their observational signatures on geometry universe cosmic history structure formation. The optimised for two independent primary probes: Weak gravitational Lensing (WL) Baryonic Acoustic Oscillations (BAO). payload consists 1.2 m Korsch telescope provide large...
The answer is Yes! We indeed find that interacting dark energy can alleviate the current tension on value of Hubble constant $H_0$ between Cosmic Microwave Background anisotropies constraints obtained from Planck satellite and recent direct measurements reported by Riess et al. 2016. combination these two datasets points towards an evidence for a non-zero matter-dark coupling $\xi$ at more than standard deviations, with $\xi=-0.26_{-0.12}^{+0.16}$ $95\%$ CL. However better solved when...
The recent determination of the local value Hubble constant by Riess et al, 2016 (hereafter R16) is now 3.3 sigma higher than derived from most CMB anisotropy data provided Planck satellite in a LCDM model. Here we perform combined analysis and R16 results an extended parameter space, varying simultaneously 12 cosmological parameters instead usual 6. We find that phantom-like dark energy component, with effective equation state $w=-1.29_{-0.12}^{+0.15}$ at 68 % c.l. can solve current tension...
We explore whether nonstandard dark sector physics might be required to solve the existing cosmological tensions. The properties we consider in combination are (a) an interaction between matter and energy components (b) a equation of state $w$ different from that canonical constant $w=\ensuremath{-}1$. In principle, these two parameters independent. practice, avoid early-time, superhorizon instabilities, their allowed parameter spaces correlated. Moreover, clear degeneracy exists case cosmic...
Within the standard three-neutrino framework, absolute neutrino masses and their ordering (either normal, NO, or inverted, IO) are currently unknown. However, combination of current data coming from oscillation experiments, neutrinoless double beta decay searches, cosmological surveys, can provide interesting constraints for such unknowns in sub-eV mass range, down to O(0.1) eV some cases. We discuss limits on observables by performing a global analysis, that includes latest results bounds...
A new time-dependent, scale-independent parameter, $\ensuremath{\varpi}$, is employed in a phenomenological model of the deviation from general relativity which Newtonian and longitudinal gravitational potentials slip apart on cosmological scales as dark energy, assumed to be arising theory gravitation, appears dominate Universe. comparison presented between $\ensuremath{\varpi}$ other parametrized post-Friedmannian models literature. The effect cosmic microwave background anisotropy...
The injection of secondary particles produced by dark matter (DM) annihilation around redshift $\ensuremath{\sim}1000$ would inevitably affect the process recombination, leaving an imprint on cosmic microwave background (CMB) anisotropies and polarization. We show that most recent CMB measurements provided WMAP satellite mission place interesting constraints DM self-annihilation rates, especially for models exhibit a large Sommerfeld enhancement cross section, as recently proposed to fit...
We summarize the utility of precise cosmic microwave background (CMB) polarization measurements as probes physics inflation. focus on prospects for using CMB to differentiate various inflationary mechanisms. In particular, a detection primordial B‐mode would demonstrate that inflation occurred at very high energy scale, and inflaton traversed super‐Planckian distance in field space. explain how such or constraint illuminate aspects Planck scale. Moreover, can constrain scale‐dependence...
We show that a general late-time interaction between cold dark matter and vacuum energy is favored by current cosmological data sets. characterize the strength of coupling dimensionless parameter q(V) free to take different values in four redshift bins from primordial epoch up today. This interacting scenario agreement with measurements cosmic microwave background temperature anisotropies Planck satellite, supernovae Ia Union 2.1 space distortions number surveys, as well combinations these...
PRISM (Polarized Radiation Imaging and Spectroscopy Mission) was proposed to ESA in May 2013 as a large-class mission for investigating within the framework of Cosmic Vision program set important scientific questions that require high resolution, sensitivity, full-sky observations sky emission at wavelengths ranging from millimeter-wave far-infrared. PRISM's main objective is explore distant universe, probing cosmic history very early times until now well structures, distribution matter,...
In the current $3\ensuremath{\nu}$ paradigm, neutrino flavor oscillations probe three mixing angles $({\ensuremath{\theta}}_{12},{\ensuremath{\theta}}_{23},{\ensuremath{\theta}}_{13})$, one $CP$-violating phase $\ensuremath{\delta}$, and two independent differences between squared masses ${m}_{i}^{2}$, that can be chosen as $\ensuremath{\delta}{m}^{2}={m}_{2}^{2}\ensuremath{-}{m}_{1}^{2}>0$ $\mathrm{\ensuremath{\Delta}}{m}^{2}={m}_{3}^{2}\ensuremath{-}({m}_{1}^{2}+{m}_{2}^{2})/2$, where...
Dynamical dark energy has been recently suggested as a promising and physical way to solve the 3.4 sigma tension on value of Hubble constant $H_0$ between direct measurement Riess et al. (2016) (R16, hereafter) indirect constraint from Cosmic Microwave Anisotropies obtained by Planck satellite under assumption $\Lambda$CDM model. In this paper, parameterizing evolution using $w_0$-$w_a$ approach, considering $12$ parameter extended scenario, we find that: a) can indeed be solved with...
The study of polarized dust emission has become entwined with the analysis cosmic microwave background (CMB) polarization. We use new Planck maps to characterize Galactic as a foreground CMB present EE, BB, and TE power spectra polarization at 353 GHz for six nested sky regions covering from 24 71 % sky. power-law fits angular spectra, yielding evidence statistically significant variations exponents over difference between values EE BB spectra. correlation E/B asymmetry extend low multipoles...
Abstract We show that a combined analysis of cosmic microwave background anisotropy power spectra obtained by the Planck satellite and luminosity distance data simultaneously excludes flat universe cosmological constant at 99% confidence level. These results hold separately when combining with three different sets: two determinations Hubble from Riess et al. Freedman al., Pantheon catalog high-redshift Type Ia supernovae. conclude either Lambda cold dark matter model needs to be replaced...
Abstract The measurements of cosmic microwave background (CMB) anisotropies made by the Planck satellite provide extremely tight upper bounds on total neutrino mass scale (Σ m ν < 0.26 eV at 95% C.L.). However, as recently discussed in literature, data show anomalies that could affect this result. Here we new constraints masses using recent and complementary CMB from Atacama Cosmology Telescope DR4 South Pole SPT-3G experiments. We found both ACT-DR4 data, when combined with WMAP, mildly...