The Parametrized Post-Newtonian-Vainshteinian formalism

Light degrees of freedom that modify gravity on cosmological scales must be "screened" on solar system scales in order to be compatible with data. The Vainshtein mechanism achieves this through a breakdown of classical perturbation theory, as large interactions involving new degrees of freedom become important below the so-called Vainshtein radius. We begin to develop an extension of the Parameterized Post-Newtonian (PPN) formalism that is able to handle Vainshteinian corrections. We argue that theories with a unique Vainshtein scale must be expanded using two small parameters. In this Parameterized Post-Newtonian-Vainshteinian (PPNV) expansion, the primary expansion parameter that controls the PPN order is, as usual, the velocity v. The secondary expansion parameter, α, controls the strength of the Vainshteinian correction and is a theory-specific combination of the Schwarzschild radius and the Vainshtein radius of the source that is independent of its mass. We present the general framework and apply it to Cubic Galileon theory both inside and outside the Vainshtein radius. The PPNV framework can be used to determine the compatibility of such theories with solar system and other strong-field data

Estimating the mass of galactic components using machine learning algorithms

The estimation of the bulge and disk massses, the main baryonic components of a galaxy, can be performed using various approaches, but their implementation tend to be challenging as they often rely on strong assumptions about either the baryon dynamics or the dark matter model. In this work, we present an alternative method for predicting the masses of galactic components, including the disk, bulge, stellar and total mass, using a set of machine learning algorithms: KNN-neighbours (KNN), Linear Regression (LR), Random Forest (RF) and Neural Network (NN). The rest-frame absolute magnitudes in the ugriz-photometric system were selected as input features, and the training was performed using a sample of spiral galaxies hosting a bulge from Guo's mock catalogue \citep{Guo-Catalog} derived from the Millennium simulation. In general, all the algorithms provide good predictions for the galaxy's mass components ranging from $10^9\,M_\odot$ to $10^{11}\,M_\odot$, corresponding to the central region of the training mass domain; however, the NN give rise to the most precise predictions in comparison to other methods. Additionally, to test the performance of the NN architecture, we used a sample of observed galaxies from the SDSS survey whose mass components are known. We found that the NN can predict the luminous masses of disk-dominant galaxies within the same range of magnitudes that for the synthetic sample up to a $99\%$ level of confidence, while mass components of galaxies hosting larger bulges are well predicted up to $95\%$ level of confidence. The NN algorithm can also bring up scaling relations between masses of different components and magnitudes.Comment: 13 pages, 5 figures and 1 table. Comments are welcom

Analysis of DDM into Gamma Radiation

We are interested in the purpose of a dipolar fermionic particle as a viable candidate of Dark Matter (DDM). Then, we study the annihilation of dark matter into photons, considering it as a neutral particle with non-vanishing magnetic (M) and electric (D) dipolar moments. The total annihilation cross section σ(χ → γ) is computed by starting from a general form of coupling χγ in a framework beyond to Standard Model (BSM). We found that candidates with O(mχ )∽102GeV, D≈10−16 e cm are required in order to satisfy the current cosmic relic density

Solving the Schrodinger Poisson System using the coordinate Adaptive Moving Mesh method

In this paper, we implement the Adaptive Moving Mesh method (AMM) to the solution of initial value problems involving the Schr\"odinger equation, and more specifically the Schr\"odinger-Poisson system of equations. This method is based on the solution of the problem on a discrete domain, whose resolution is coordinate and time-dependent, and allows to dynamically assign numerical resolution in terms of desired refinement criteria. We apply the method to solve various test problems involving stationary solutions of the SP system, and toy scenarios related to the disruption of subhalo s made of ultralight bosonic dark matter traveling on top of host galaxies.Comment: 12 Figures. Accepted for publication in Physical Review

A revolução da Gabriela: o ano de 1977 em Portugal

Este trabalho apresenta os contextos da visionação, em 1977, da telenovela brasileira Gabriela, Cravo e Canela. Justifica-se a escolha do Corpus – dois diários (Diário de Notícias, Diário de Lisboa) e dois semanários (Expresso e O Jornal) explicitando-se as metodologias utilizadas na análise de imprensa. Faz-se o levantamento da agenda da telenovela Gabriela, Cravo e Canela nos quatro jornais seleccionados, confrontando-a com outra agenda, mais lata, da expansão e divulgação da indústria cultural brasileira em Portugal. Considera-se que o êxito desta telenovela antecipa a emergência de uma nova sociedade e estilos de vida, bem como uma outra imagem da mulher, centrados em novos valores, no consumo e nos media.This work describes the reception of the Brazilian telenovela Gabriela, Cravo e Canela in the year of 1977 in Portugal. The corpus is composed of two daily newspapers (Diário de Notícias, Diário de Lisboa) and two weekly papers (Expresso e O Jornal); The methods of analisys are presented. Afterwards the Agenda of the telenovela Gabriela... is identified in these newspapers and compared with the Agenda of Brasilian Cultural Industry in Portugal. The conclusion aims at a relation between the exhibition of the telenovela and the rise of a new society with new women’s models and life styles

Comparison of Einstein-Boltzmann solvers for testing general relativity

We compare Einstein-Boltzmann solvers that include modifications to general relativity and find that, for a wide range of models and parameters, they agree to a high level of precision. We look at three general purpose codes that primarily model general scalar-tensor theories, three codes that model Jordan-BransDicke (JBD) gravity, a code that models fðRÞ gravity, a code that models covariant Galileons, a code that models Horava-Lifschitz gravity, and two codes that model nonlocal models of gravity. Comparing ˇ predictions of the angular power spectrum of the cosmic microwave background and the power spectrum of dark matter for a suite of different models, we find agreement at the subpercent level. This means that this suite of Einstein-Boltzmann solvers is now sufficiently accurate for precision constraints on cosmological and gravitational parameters

Comparison of Einstein-Boltzmann solvers for testing general relativity

We compare Einstein-Boltzmann solvers that include modifications to general relativity and find that, for a wide range of models and parameters, they agree to a high level of precision. We look at three general purpose codes that primarily model general scalar-tensor theories, three codes that model Jordan-Brans-Dicke (JBD) gravity, a code that models f(R) gravity, a code that models covariant Galileons, a code that models Hořava-Lifschitz gravity, and two codes that model nonlocal models of gravity. Comparing predictions of the angular power spectrum of the cosmic microwave background and the power spectrum of dark matter for a suite of different models, we find agreement at the subpercent level. This means that this suite of Einstein-Boltzmann solvers is now sufficiently accurate for precision constraints on cosmological and gravitational parameters

Comparison of Einstein-Boltzmann solvers for testing general relativity

We compare Einstein-Boltzmann solvers that include modifications to General Relativity and find that, for a wide range of models and parameters, they agree to a high level of precision. We look at three general purpose codes that primarily model general scalar-tensor theories, three codes that model Jordan-Brans-Dicke (JBD) gravity, a code that models f(R) gravity, a code that models covariant Galileons, a code that models Ho\v{r}ava-Lifschitz gravity and two codes that model non-local models of gravity. Comparing predictions of the angular power spectrum of the cosmic microwave background and the power spectrum of dark matter for a suite of different models, we find agreement at the sub-percent level. This means that this suite of Einstein-Boltzmann solvers is now sufficiently accurate for precision constraints on cosmological and gravitational parameters