Journal of Cosmology and Astroparticle Physics
Papers 7308
1 page of 731 pages (7,308 results)
Solid Soft Theorems.
Published on Feb 24, 2019in arXiv: High Energy Physics - Theory
Enrico Pajer (University of Cambridge), Sadra Jazayeri (University of Cambridge), Drian van der Woude3
We derive cosmological soft theorems for solids coupled to gravity. To this end, we first derive all cosmological adiabatic modes for solids, which display the interesting novelty of non-vanishing anisotropic stresses on large scales. Then, from the corresponding symmetries of the action of perturbations we compute the leading order related soft theorems using the operator product expansion. For the scalar bispectrum, we re-derive the result that Maldacena's consistency relation is recovered onl... more
Scalar field dark matter with a cosh potential, revisited.
Published on Apr 5, 2019in arXiv: Cosmology and Nongalactic Astrophysics
L. Arturo Urena-Lopez19
(Universidad de Guanajuato)
Dark matter models in which the constituent particle is an ultra-light boson have become part of the mainstream discussion in cosmology and astrophysics. At the classical level, the models are represented by the dynamics of a (real or complex) scalar field endowed with a potential that contains its self-interactions, and for this reason are generically known as scalar field dark matter models. Here, we revisit the properties of such a model with a cosh potential and compare it with other known e... more
The observable E_gstatistics
Published on Dec 22, 2018in arXiv: Cosmology and Nongalactic Astrophysics
Basundhara Ghosh2
(University of Geneva), Ruth Durrer34
(University of Geneva)
Recently Dizgah & Durrer have shown that the $E_g$ statistics, useful to test theories of modified gravity, is plagued by additional scale and bias dependent lensing contributions. In this work we develop and illustrate a method to remove these lensing terms by using in addition to the galaxy clustering data also shear data and the correlations of shear and galaxy clustering. We introduce a truly observable statistics termed $\tilde E_g$ which conserves the properties of scale and bias independe... more
Galaxy cluster Sunyaev-Zel'dovich effect scaling-relation and type Ia supernova observations as a test for the cosmic distance duality relation.
Published on May 27, 2019in arXiv: Cosmology and Nongalactic Astrophysics
R. F. L. Holanda (Federal University of Rio Grande do Norte), L. R. Colaço + 1 AuthorsR. Silva (Federal University of Rio Grande do Norte)
In this paper, we propose a new test to the cosmic distance duality relation (CDDR), $D_L=D_A(1+z)^2$, where $D_L$ and $D_A$ are the luminosity and angular diameter distances, respectively. The data used correspond to 61 Type Ia Supernova luminosity distances and $Y_{SZE}-Y_X$ measurements of 61 galaxy clusters obtained by the {\it Planck} mission and the deep XMM-Newton X-ray data, where $Y_{SZE}$ is the integrated comptonization parameter obtained via Sunyaev-Zel'dovich effect observations and... more
Is de Sitter space always excluded in semiclassical f(R) gravity
Published on Mar 19, 2019in arXiv: General Relativity and Quantum Cosmology
Roberto Casadio22
(Istituto Nazionale di Fisica Nucleare), Andrea Giugno9
(Ludwig Maximilian University of Munich)+ 1 AuthorsValerio Faraoni33
(Bishop's University)
It is shown that the recent corpuscular description of gravity generically excludes de Sitter spacetime in any semiclassical version of f(R) gravity. A phantom phenomenology of the cosmic dynamics is also naturally excluded.
Constraints on Scalar and Tensor spectra from N_{eff}
Published on Mar 28, 2019in arXiv: Cosmology and Nongalactic Astrophysics
Ido Ben-Dayan1
, Brian Keating29
+ 1 AuthorsIra Wolfson2
At the linear level, the gravitational wave (GW) spectrum predicted by inflation, and many of its alternatives, can have arbitrarily small amplitude and consequently an unconstrained tilt. However, at second order, tensor fluctuations are sourced by scalar fluctuations that have been measured in the cosmic microwave background (CMB). These second order fluctuations generically produce a minimum amount of tensor perturbations corresponding to a tensor-to-scalar ratio of $r\sim 10^{-6}$. Inverting... more
Biased Tracers of Two Fluids in the Lagrangian Picture
Published on Mar 1, 2019in arXiv: Cosmology and Nongalactic Astrophysics
Shi-Fan Chen1
(University of California, Berkeley), Emanuele Castorina11
(University of California, Berkeley), Martin White101
(University of California, Berkeley)
We explore Lagrangian perturbation theory (LPT) for biased tracers in the presence of two fluids, focusing on the case of cold dark matter (CDM) and baryons. The presence of two fluids induces corrections to the Lagrangian bias expansion and tracer advection, both of which we formulate as expansions in the three linear modes of the Lagrangian equations of motion. We compute the linear-order two-fluid corrections in the Zeldovich approximation, finding that modifications to the bias expansion and... more
Prospects of detecting dark matter through cosmic-ray antihelium with the antiproton constraints
Published on Aug 10, 2018in arXiv: High Energy Physics - Phenomenology
Nan Li (Chinese Academy of Sciences), Chun-Cheng Wei1
(Chinese Academy of Sciences)+ 1 AuthorsYu-Feng Zhou2
(Chinese Academy of Sciences)
Cosmic-ray (CR) antihelium can be an important observable for dark matter (DM) indirect searches due to extremely low secondary backgrounds towards low energies. In most DM models, the predicted CR antihelium flux is strongly correlated with that of CR antiprotons. Thus the upper limits on the DM annihilation cross sections from the current antiproton data can be used to place stringent limits on the maximal antihelium flux for the same model. Making use of the latest AMS-02 data on the antiprot... more
Lattice formulation of axion inflation. Application to preheating
Published on Dec 7, 2018in arXiv: Cosmology and Nongalactic Astrophysics
Jose Roberto Canivete Cuissa , Daniel G. Figueroa9
We present a lattice formulation of an interaction ${\phi\over\Lambda} F\tilde F$ between an axion and some $U(1)$ gauge sector with the following properties: it reproduces the continuum theory up to $\mathcal{O}(dx_\mu^2)$ corrections, it preserves exact gauge invariance and shift symmetry on the lattice, and it is suitable for self-consistent expansion of the Universe. The lattice equations of motion can no longer be solved by explicit methods, but we propose an implicit method to overcome thi... more
Dark energy and dark matter unification from dynamical space time: observational constraints and cosmological implications
Published on Apr 11, 2019in arXiv: General Relativity and Quantum Cosmology
Fotios K. Anagnostopoulos2
, David Benisty1
(Ben-Gurion University of the Negev)+ 1 AuthorsE. I. Guendelman19
(Ben-Gurion University of the Negev)
A recently proposed Dynamical Space-time Cosmology (DSC) that unifies dark energy and dark matter is studied. The general action of this scenario includes a Lagrange multiplier, which is coupled to the energy-momentum tensor and a scalar field which is different than quintessence. First, for various types of potentials, we implement a critical point analysis and we find solutions which lead to cosmic acceleration and under certain conditions to stable late-time attractors. Then the DSC cosmology... more
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