Search Publications
Dark Energy Survey year 1 results: Constraints on extended cosmological models from galaxy clustering and weak lensing
Bechtol, K.; Smith, M.; Nichol, R. C. +112 more
We present constraints on extensions of the minimal cosmological models dominated by dark matter and dark energy, Λ CDM and w CDM , by using a combined analysis of galaxy clustering and weak gravitational lensing from the first-year data of the Dark Energy Survey (DES Y1) in combination with external data. We consider four extensions of the minima…
Constraints on a Bianchi type I spacetime extension of the standard Λ CDM model
Kumar, Suresh; Akarsu, Özgür; Sharma, Shivani +1 more
We consider the simplest anisotropic generalization, as a correction, to the standard Λ CDM model, by replacing the spatially flat Robertson-Walker metric by the Bianchi type-I metric, which brings in a new term Ωσ 0a-6 (mimicking the stiff fluid) in the average expansion rate H (a ) of the Universe. From Hubble and Pantheon …
Cosmological constraints on neutrino self-interactions with a light mediator
Lattanzi, Massimiliano; Natoli, Paolo; Forastieri, Francesco
If active neutrinos undergo nonstandard ("secret") interactions (NS ν Is ), the cosmological evolution of the neutrino fluid might be altered, leaving an imprint in cosmological observables. We use the latest publicly available CMB data from Planck to constrain NS ν Is inducing ν -ν scattering, under the assumption that the mediator ϕ of the secre…
Cosmological constraints on post-Newtonian parameters in effectively massless scalar-tensor theories of gravity
Rossi, Massimo; Ballardini, Mario; Braglia, Matteo +4 more
We study the cosmological constraints on the variation of Newton's constant and on post-Newtonian parameters for simple models of the scalar-tensor theory of gravity beyond the extended Jordan-Brans-Dicke theory. We restrict ourselves to an effectively massless scalar field with a potential V ∝F2, where F (σ )=Npl2…
Primordial gravitational waves and the H0-tension problem
Benetti, Micol; Graef, Leila L.; Alcaniz, Jailson S.
We analyze the H0-tension problem in the context of models of the early universe that predict a blue tilted spectrum of primordial gravitational waves (GWs), which is a positive value of the tensor tilt nT. By considering the GW's contribution, NeffGW, to the effective number of relativistic degrees of f…
Cosmological discordances. III. More on measure properties, large-scale-structure constraints, the Hubble constant and Planck data
Ishak, Mustapha; Lin, Weikang; Garcia-Quintero, Cristhian +1 more
Consistency between cosmological datasets is essential for ongoing and future cosmological analyses. We first investigate the questions of stability and applicability of some moment-based inconsistency measures to multiple datasets. We show that the recently introduced index of inconsistency (IOI) is numerically stable while it can be applied to m…
Arbitrariness of potentials in interacting quintessence models
Bamba, Kazuharu; Roy, Nandan
Though we have entered an era of high precision cosmology the form of the quintessence potentials still remain arbitrary. In this work we explore the interacting quintessence models considering a parametrization of the quintessence potentials and tried to constrain the form of potentials using the recent cosmological observations. The particular p…
Reconstructing the weak lensing magnification distribution of type Ia supernovae
Wang, Yun; Zhai, Zhongxu
Weak lensing of type Ia supernovae (SNe Ia) is a systematic uncertainty in the use of SNe Ia as standard candles, as well as an independent cosmological probe, if the corresponding magnification distribution can be extracted from data. We study the peak brightness distribution of SNe Ia in the Pantheon sample and find that the high-z subsample sho…