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Mini-courses, Seminars and Posters

List of Participants

Program

Venue and Accommodation

Additional details on some of the School activities can be found below.

Mini-courses

 Dark Energy - Luca Amendola (Universität Heidelberg, Germany)

1) The cosmological constant and beyond
2) The general scalar field model and its properties
3) Basic observables for DE  and how can we measure them in a model-independent way
4) Tests of dark energy and modified gravity from clusters and gravitational waves
5) The Euclid satellite
​
Modified Gravity - Federico Piazza (Aix Marseille Université, France)

1) general relativity as the only consistent massless spin-2 theory
2) symmetry breaking patterns in cosmology
3) the case of a scalar field, scalar tensor theories, solar system tests
4) effective field theory of cosmological perturbations in the presence of a scalar field.
5) phenomenology of dark energy
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Large Scale Structure and Weak Lensing  - Scott Dodelson (Fermilab, USA) 

1) Background cosmology: FRW, Friedmann eqn, thermal history, epoch of equality, neutrino production, current epoch of acceleration
2) Clustering Statistics; Linear Perturbation generation and growth; Impact of DE on [linear] matter power spectrum
3) Shape of P(k), Neutrinos, Lightning overview of inflation, Surveys, Galaxy clustering, BAO
4) Anisotropies in the CMB
5) Weak Lensing, Cross-Correlation with CMB

Particle Dark Matter - Stefano Profumo (University of California Santa Cruz, USA)

1) Particle Dark Matter: the Name of the Game
2) WIMP Dark Matter: zeroth-order Lessons from Cosmology
3) WIMP Relic Density, a Closer Look
4) The Art of WIMP Direct Detection
5) Indirect WIMP Dark Matter Searches
6) Not-so-Indirect WIMP Searches: Neutrinos and Gamma Rays
7) Axions as Dark Matter Particles
8) Sterile Neutrinos as Dark Matter Particles
9) Bestiarium: a short compendium of notable Dark Matter particle candidates

Seminars

Modelling the crosscorrelation between cluster counts and angular power spectrum
Rogerio Rosenfeld (IFT)

We show how to model the  cross-correlation between cluster counts and angular power spectrum within the halo model and derive sensitivity to the parameters from future surveys.​

Strong Lensing and the Dark Sections 
​Martin Makler (CBPF)

Screening Mechanisms
Jose Beltran Jimenez (CPT, Universite d'Aix-Marseille)

​The discovery of the accelerated expansion of the universe has motivated an intense activity in infrarred modifications of gravity with an additional scalar degree of freedom. This scalar is then used to replace the cosmological constant as the responsible for the cosmic acceleration. A common problem in these models is that this scalar must be very light to have cosmological effects today. However, it typically mediates a long-range force that has not been observed in local gravity tests and this severely constraints such models. A resolution to this problem came about with the implementation of screening mechanisms that allow to avoid local gravity tests while still having relevant cosmological effects. I will review some models featuring the different screening mechanism existing in the literature and how they work to evade local gravity tests. However,  evading Solar System bounds leads in many cases to tight constraints for the cosmological evolution of the scalar field. For the chameleon/symmetron models, the local gravity constraints prevents the scalar to drive self-accelerated solutions and, furthermore, to have an impact in structure formation at linear scales. For a class of theories featuring a Vainshtein mechanism, I will argue how the cosmological evolution of the field can induce non-screenable effects in local gravity observables, mainly a time-variation in Newton's constant and an anomalous propagation speed of gravitational waves. These effects are then constrained using solar system and binary pulsar constraints. 

Massive Gravity
Lavinia Heisenberg (Institute for Theoretical Studies, ETH Zurich)

Numerical Cosmology
Sandro Dias Pinto Vitenti (CBPF)

The NumCosmo is a free software C library whose main purposes are to test cosmological and astrophysical models using observational data. NumCosmo has currently a variety of cosmological models and derived quantities ranging from the primordial universe until today. Each cosmological quantity accounts for different features and are related with different observational probes. For these reasons, NumCosmo provides a structure that allows the implementation of each part in different ways. For instance,  the primordial power spectrum of adiabatic curvature perturbations can be a simple power law, a phenomenological model or a spectrum obtained from the numerical evolution of a inflationary model. This allows the user to change between these options regardless the remaining components of the model, i.e., the Boltzmann equations, non-linear matter power spectrum, dark matter and dark energy sectors, etc. The observational data module follows the same design. The likelihood is divided in many data models which represent uncorrelated data that can be seamlessly combined when performing statistical analysis of the models. In this talk we present a brief overview of the NumCosmo given working examples of the primordial power spectrum analysis using different phenomenological models and Cosmic Microwave Background data.

Calibrating the Planck Cluster Mass Scale with CLASH
Mariana Penna Lima Vitenti (Paris Diderot University)

We determine the mass scale of \Planck\ galaxy clusters using gravitational lensing mass measurements from the Cluster Lensing And Supernova survey with Hubble (CLASH).  We compare the lensing masses to the \Planck\ Sunyaev-Zeldovich (SZ) mass proxy for 21 clusters in common, employing a Bayesian analysis to simultaneously fit a parameterized CLASH selection function and the distribution between the measured observables and true cluster mass.  In the case of an assumed constant bias, $\bsz$, between true cluster mass, $\Mfive$, and the \Planck\ mass proxy, $\Mpl$, our analysis constrains $1-\bsz = 0.73\pm 0.10$. The constraints are robust to modeling assumptions, with our estimates for $1-\bsz$ in six different case studies in agreement (at 68.3\% confidence) with the sample mean ratio, $\langle \Mpl/\Mcl\rangle =0.72\pm 0.059$, where $\Mcl$ is the CLASH lensing mass.  The Bayesian analysis allows more complete modeling of astrophysical effects and hence provides more reliable uncertainties.  Our constraint on the cluster mass scale is consistent with recent results from the Weighing the Giants programme and the Canadian Cluster Comparison Project.

Communications

Model-independent tests in cosmology
Vinicius Consolini Busti (Instituto de Física - USP)

The unprecedented amount of data gathered for cosmological studies in the last two decades revolutionized the field, allowing the establishment of a standard model in cosmology, known as Lambda CDM. In this data-driven scenario, many tests can be performed in order to check several cosmological hypotheses, as well as the nature of the basic components of the standard model. In this talk, I will briefly present results of testing some relations in cosmology, as the distance duality relation and a consistency test for the LCDM model, as well as ways to obtain some cosmological parameters in a model-independent way, as the Hubble constant. Finally, I will follow the opposite route and show that cosmological measurements can put constraints in astrophysical environments, as the baryon fraction observed in massive galaxy clusters.

The diagnostic of Horndeski theories with the effective field theory of dark energy
Louis Perenon (Aix-Marseille Université)

Modified gravity has become an important field in cosmology especially in the quest for explaining cosmic acceleration. I wish to present a novel approach, the effective field theory of dark energy. This allows one to study in a unified way, all modified gravity models containing a single scalar field non-minimally coupled to the metric. Then, I will show how a rich phenomenology of large scale structures observables arises within this approach. I would like to finish by highlighting how certain correlations between these observables allows one to discard between modified gravity theories or as to the type of dark energy embedded within these theories.

Anomaly-induced inflation and gravitational stability
Ilya Shapiro (UFJF)

Integration of conformal anomaly is the simplest and of the most efficient ways to derive quantum corrections to the gravitational action. One of the applications is a generalized form of Starobinsky inflation, which includes the usual unstable and also stable version. We discuss a recent progress in describing the possible transition between these two phases of the early universe history. 

The general form of the coupled Horndeski Lagrangian that allows cosmological scaling solutions 
​Adalto R. Gomes (UFMA)

We consider the general scalar eld Horndeski Lagrangian coupled to dark matter. Within this class of models, we present two results that are independent of the
particular form of the model. First, we show that in a Friedmann-Robertson-Walker metric
the Horndeski Lagrangian coincides with the pressure of the scalar eld. Second, we employ
the previous result to identify the most general form of the Lagrangian that allows for cosmological
scaling solutions, i.e. solutions where the ratio of dark matter to eld density and
the equation of state remain constant. Scaling solutions of this kind may help solving the
coincidence problem since in this case the presently observed ratio of matter to dark energy
does not depend on initial conditions, but rather on the theoretical parameters.

Instability in interacting dark sector: An appropriate Holographic Ricci dark energy model
Nelson Videla (University of Chile)

In this paper we investigate the consequences of phantom crossing considering the perturbative dynamics in models with interaction in their dark sector. By mean of a general study of gauge-invariant variables in comoving gauge, we relate the sources of instabilities in the structure formation process with the phantom crossing. In order to illustrate these relations and its consequences in more detail, we consider a specific case of an holographic dark energy interacting with dark matter. We find that in spite of the model is in excellent agreement with observational data at background level, however it is plagued of instabilities in its perturbative dynamics. We reconstruct the model in order to avoid these undesirable instabilities, and we show that this implies a modification of the concordance model at background. Also we find drastic changes on the parameters space in our model when instabilities are avoided.

A study of the covariance of the angular power spectrum using Gaussian and Log-normal simulations: effects of cut skies
​Nickolas Kokron​ (Instituto de Física Teórica - UNESP)

We study the problem of estimating the covariance matrix of the angular power spectrum of galaxy clustering in the context of a cut-sky redshift survey. We use both Gaussian and Log-normal simulated density fields and compare these to theoretical predictions of covariance matrices found in the literature. Accurately estimating this covariance matrix is of critical importance in estimating the scale of baryon acoustic oscillations in order to constrain cosmological parameters.

Cosmological dynamics of spatially flat EinsteinGauss-Bonnet models in various dimensions
Sergey Pavluchenko (UFMA)

We perform a systematic study of spatially flat anisotropic ((3+D)+1)-dimensional Einstein-Gauss-Bonnet cosmological models. We consider models which topologically are the product of two flat isotropic submanifolds with different scale factors. One of these submanifolds is three-dimensional and represents our 3D space and the other is D-dimensional and represents extra dimensions. We consider no ansatz on the scale factors, which makes our results quite general. With both Einstein-Hilbert and Gauss-Bonnet contributions in play and with the symmetry involved, the cases with D=1, D=2, D=3 and D>= 4 have different dynamics due to different structure of the equations of motion. We analytically analyze equations of motion in all cases and describe all possible regimes.