Search Publications
Experimental results from the ST7 mission on LISA Pathfinder
Mendes, L.; Anderson, J.; Cooper, M. +146 more
The Space Technology 7 Disturbance Reduction System (ST7-DRS) is a NASA technology demonstration payload that operated from January 2016 through July 2017 on the European Space Agency's (ESA) LISA Pathfinder spacecraft. The joint goal of the NASA and ESA missions was to validate key technologies for a future space-based gravitational wave observat…
Gravitational waves and the polarizations in Hořava gravity after GW170817
Gong, Yungui; Hou, Shaoqi; Papantonopoulos, Eleftherios +1 more
The gravitational waves of Hořava gravity, their polarization states, and their possible observational signatures are discussed. Using the gauge-invariant variable formalism, we find the three polarization modes in Hořava gravity excited by the three physical degrees of freedom contained in this theory. In particular, the scalar degree of freedom …
Tensions between direct measurements of the lens power spectrum from Planck data
Hu, Wayne; Motloch, Pavel
We apply a recently developed method to directly measure the gravitational lensing power spectrum from CMB power spectra to the Planck satellite data. This method allows us to analyze the tension between the temperature power spectrum and lens reconstruction in a model-independent way. Even when allowing for arbitrary variations in the lensing pow…
Cosmological constraints and comparison of viable f (R ) models
Nesseris, Savvas; Pérez-Romero, Judit
In this paper we present cosmological constraints on several well-known f (R ) models, but also on a new class of models that are variants of the Hu-Sawicki one of the form f (R )=R -2/Λ 1 +b y (R ,Λ ) , that interpolate between the cosmological constant model and a matter dominated universe for different values of the parameter b , which is usual…
Bayesian evidences for dark energy models in light of current observational data
Lonappan, Anto. I.; Kumar, Sumit; Ruchika +2 more
We do a comprehensive study of the Bayesian evidences for a large number of dark energy models using a combination of latest cosmological data from SNIa, CMB, BAO, strong lensing time delay, growth measurements, measurements of Hubble parameter at different redshifts and measurements of angular diameter distance by Megamaser Cosmology Project. We …
Updated observational constraints on quintessence dark energy models
Ichiki, Kiyotomo; Sugiyama, Naoshi; Ooba, Junpei +1 more
The recent GW170817 measurement favors the simplest dark energy models, such as a single scalar field. Quintessence models can be classified in two classes, freezing and thawing, depending on whether the equation of state decreases towards -1 or departs from it. In this paper, we put observational constraints on the parameters governing the equati…
Astrometric effects of gravitational wave backgrounds with non-Einsteinian polarizations
Gilmore, Gerard; Mihaylov, Deyan P.; Moore, Christopher J. +2 more
The Gaia mission offers a new opportunity to search for the low-frequency gravitational wave background using astrometric measurements. In this paper, the astrometric effect of gravitational waves is reviewed, with a particular focus on the effect of non-Einsteinian gravitational wave polarizations. A stochastic gravitational wave background gener…
Precision charge control for isolated free-falling test masses: LISA pathfinder results
Mendes, L.; Russano, G.; Lloro, I. +83 more
The LISA Pathfinder charge management device was responsible for neutralizing the cosmic-ray-induced electric charge that inevitably accumulated on the free-falling test masses at the heart of the experiment. We present measurements made on ground and in flight that quantify the performance of this contactless discharge system which was based on p…
Cornering the P l a n c k Alens tension with future CMB data
Di Valentino, Eleonora; Melchiorri, Alessandro; Renzi, Fabrizio
The precise measurements of cosmic microwave background (CMB) anisotropy angular power spectra made by the Planck satellite show an anomalous value for the lensing amplitude, defined by the parameter Alens, at about 2 standard deviations (2.6 standard deviations when cosmic shear data are included). Moreover, considering Alens
Measurement of the thermal Sunyaev-Zel'dovich effect around cosmic voids
Spergel, David N.; Alonso, David; Hill, J. Colin +1 more
We stack maps of the thermal Sunyaev-Zel'dovich effect produced by the Planck Collaboration around the centers of cosmic voids defined by the distribution of galaxies in the CMASS sample of the Baryon Oscillation Spectroscopic Survey, scaled by the void effective radii. We report a first detection of the associated cross-correlation at the 3.4 σ l…