Since its discovery, the study of the cosmic microwave background anisotropies has been pursued from space, balloons and the ground with great success. The results have helped in shaping the current standard cosmological model, and forged the new questions we are now trying to answer. I will review the main legacy of past experiments, and discuss the scientific goals and expectations for the...
ESA's Euclid satellite, designed to map the geometry of the Universe and scheduled for launch in 2023, will observe billions of galaxies with the ultimate goal of unveiling the nature of dark matter and dark energy. I will give an overview of the instrument and the current status of the Euclid mission. I will then focus on one of its main probes, galaxy clustering, and describe the...
In this talk, we explore the possibility of primordial black holes (PBHs) forming from the gravitational collapse of either the structures virialized during reheating (referred as inflaton halos or inflaton clusters), or from the collapse of the central core of these configurations (referred as inflaton stars). We compute the threshold amplitude for the density contrast to undergo this...
Precise measurements at small angles of the cosmic microwave background (CMB) angular power spectrum (APS), done by the Planck collaboration, have stimulated accurate analyses of the lensing amplitude parameter $A_L$ to confirm if it satisfies the value expected by the flat $\Lambda$CDM concordance model, i.e. $A_L = 1$.
We discuss a possible excess in the Planck APS not accounted by the...
We present a fully differential, field level emulator for large-scale structure formation that is accurate in the deeply nonlinear regime. Our emulator consists of two convolutional neural networks trained to output the nonlinear displacements and velocities of N-body simulation particles based on their linear inputs. Cosmology dependence is encoded in the form of style parameters at each...
Antisymmetric tensor field (two-form field) is a ubiquitous component in string theory and generally couples to the scalar sector through its kinetic term. In this paper, we propose a cosmological scenario that the particle production of two-form field, which is triggered by the background motion of the coupled inflaton field, occurs at the intermediate stage of inflation and generates the...
We examine the validity of the classical approximation of the waterfall phase transition in hybrid inflation from an effective field theory (EFT) point of view. The EFT is constructed by integrating out the waterfall field fluctuations, up to one-loop order in the perturbative expansion. Assuming slow-roll conditions are obeyed, right after the onset of the waterfall phase, we find the...
A new and promising technique for observing the Universe and study the dark sector is the intensity mapping of the redshifted 21-cm line of neutral hydrogen (HI). The Baryon Acoustic Oscillations [BAO] from Integrated Neutral Gas Observations (BINGO) radio telescope will use the 21-cm line to map the Universe in the redshift range $0.127 \le z \le 0.449$, in a tomographic approach, with the...
Covariance matrices are a fundamental component in the process of constraining physical models from observations, determining the sensibility of the dataset to modifications in the model parameters. However, estimating them correctly presents many challenges; in particular, when computing this quantity using simulations, one must assume a galaxy formation model and a set of fiducial...
We re-examine sterile neutrino dark matter in gauged $U(1)_{B-L}$ model. Improvements have been made by proper inclusion of all relevant processes and tracing the evolution of the number densities of sterile neutrino and extra neutral gauge boson $Z'$. The energy density of $Z'$ turns out to to be much greater than in earlier studies. We revise the space of the viable parameters .
We study the polarizations of gravitational waves (GWs) in generic higher-curvature gravity (HCG) whose Lagrangian is an arbitrary polynomial of the Riemann tensor. On a flat background, the linear dynamical degrees of freedom in this theory are identified as massless spin-2, massive spin-2, and massive spin-0 fields. Employing a fully gauge-invariant formalism, we demonstrate that (i) the...
We present a finite temperature model for dark matter. In this work, we show coupled equations for self-interacting scalar dark matter which can include both a condensed, low momentum fuzzy component and one with higher momenta that may be described as a collection of classical particles. We do this from first principles, using two distinct but equivalent approaches: firstly via the...
In general, modified gravity theories can be seen as dark energy theories using the effective fluid approach. In this work, we apply this formalism to the most general second-order scalar-vector-tensor (SVT) theory of gravity. This will allow us to encompass all the free functions of the theory in terms of the equation of state, speed of sound, velocity, and anisotropic stress of a very...
Gravitational production of massive particles due to cosmic expansion can be significant during the inflationary and reheating period of the Universe. In this work, we focus on the gravitational production of light vector bosons that couple feebly to the Standard Model (SM) particles. Due to the very feeble coupling, the light vector bosons never reach thermal equilibrium and if the Hubble...
In this paper, we have emphasized the stability analysis of the accelerating cosmological models obtained in $f(T)$ gravity theory. The behaviour of the models based on the evolution of the equation of state parameter shows phantom-like behaviour at the present epoch. The scalar perturbation technique is used to create the perturbed evolution equations, and the stability of the models has been...
A prediction of the standard LCDM cosmological model is that dark matter (DM) halos are teeming with numerous self-bound substructure, or subhalos. The most massive ones host the observed dwarf satellite galaxies, while smaller subhalos may host no stars/gas at all and thus may have no visible astrophysical counterparts and would remain completely dark. Yet, some of these ‘dark satellites’ are...
The first three observing runs of the LIGO-Virgo-KAGRA detector network have led to 90 detections of compact binary coalescences and have ushered in a wealth of results in fundamental physics, astrophysics and cosmology. In this talk we give a brief overview of the observations and focus on standard-siren cosmology, namely the use of compact binaries as standard distance indicators to measure...
The HIBEAM/NNBAR experiment is a two stage experiment for the European Spallation
Source (ESS) to search for baryon number violation. The experiment would make high sensitivity searches for baryon number violating processes: n → nbar and n → n′(neutron to sterile neutron), corresponding to the selection rules in baryon number ΔB = 2, 1 , respectively. The experiment addresses topical open...
The Dark Energy Survey (DES) is a 5000 square degree galaxy imaging survey which completed six years of observations in 2019. By measuring the shapes and colors of more than 200 million galaxies in addition to conducting a supernova survey, DES is a multi-purpose experiment that is able to study the large-scale properties of the Universe using measurements of weak gravitational lensing, galaxy...
I will review the role that galaxy clusters have as tracers of growth of cosmic structures and to constrain the Dark Sector of the Universe. After overviewing the current state of cluster cosmology, I will show one example of cosmic tension arising when comparing cosmological posteriors derived from galaxy clusters and Lyman-alpha forest. Within this context, I will critically discuss the...
Phase correlations have been proposed as an efficient higher-order statistic able to extract cosmological and astrophysical information that is largely independent from the two-point function or power spectrum. In this talk, we develop an estimator for the line correlation function of projected fields, corresponding to the correlation between the harmonic-space phases of the field at three...
The detection of gravitational waves (GW) has opened a new window for cosmology. The current tension between the measurement of the Hubble constant H0 from Cosmic Microwave Background and Supernova analyses makes an independent, standard siren measurement of H0 from gravitational waves particularly interesting.
However, up to date, the astronomical community has confidently identified only...
I will describe recent developments on the nonlinear modelling of LSS, in the context of momentum-exchange interacting dark energy. I will review the Dark Scattering model and show how it can alleviate the current $S_8$ tension between early and late-Universe data. I will present new constraints on this interaction from a likelihood analysis of the BOSS DR12 power spectrum multipoles, while...
Since the first gravitational wave detection from a merging binary black hole system by the large interferometers LIGO, a new window of the Universe was opened leading us to use these waves to probe the expansion of the Universe. Gravitational wave sources with electromagnetic counterparts, called bright standard sirens, are very useful to cosmology as their luminosity distances can be...
In this talk, I will present a method to extract the Scalar Vector Tensor (SVT) first order perturbations from the Cosmological Perturbations Theory developed in a homogeneous and isotropic Geodesic Light Cone (GLC) background. Due to its adapted light-cone decomposition, the GLC-SVT relation becomes involved, notwithstanding, I will present two different strategies to easy this relation. In...
We investigate a recently proposed method for measuring the Hubble constant from gravitational wave detections of binary black hole coalescences without electromagnetic counterparts. In the absence of a direct redshift measurement, the missing information on the left-hand side of the Hubble-Lemaître law is provided by the statistical knowledge on the redshift distribution of sources. We assume...
Axionlike particles (ALPs) are among the most well-motivated extensions of the Standard Model of particle physics, and are increasingly popular dark matter candidates. Extreme astrophysical environments, such as dense and hot supernovae, or vast and magnetised galaxy clusters, provide unique opportunities to test the theory. In this talk, I will discuss recent progress in searching for ALPs...
Axions are often accompanied by discrete symmetries that are
spontaneously broken in the early universe and lead to the formation of
a network of cosmic domain walls (DW).
In this talk, I will discuss the stochastic gravitational wave (GW)
background produced by such networks. I will show that in some heavy QCD
axion models, the GW signal is within reach of current and future
detectors...
We study axion dark matter production from a misalignment mechanism in scenarios featuring a general nonstandard cosmology. Before the onset of Big Bang nucleosynthesis, the energy density of the universe is dominated by a particle field $\phi$ described by a general equation of state $\omega$. The ensuing enhancement of the Hubble expansion rate decreases the temperature at which axions start...
We report on the status and latest results of the KM3NeT neutrino telescope in the Mediterranean Sea. KM3NeT has two detectors, KM3NeT/ORCA in France, optimized for the measurement of atmospheric neutrinos, and KM3NeT/ARCA in Italy, focussed on the detection of cosmic neutrinos. Although the detector is still under construction, first results with data using configurations of six lines in ORCA...
This talk will provide an overview of neutrinos in physics, astrophysics and cosmology. I will broadly cover detection of neutrinos over a wide range of energies, highlighting several ongoing and future projects.
With the recent development of projects for the gathering of cosmological data through radioastronomy, mainly using the redshifted 21 cm signal line, various systematic effects have been analysed to improve sensibility and precision. This includes instrumental features such as beam analysis, which involves studying the how the reflectors modify the data through optical aberrations, and how it...
The nature of dark matter is one of the outstanding open questions in physics. Although the observational evidence for the existence of a non-baryonic, non-luminous and non-relativistic component of the universe has been strengthen in recent years, its nature still remains unknown. A class of theoretically-motivated non-relativistic particles with masses approximately in the GeV to TeV range,...
I will review recent progress to address the generation of primordial non-Gaussianity during cosmic inflation. I will focus my attention on the origin of non-Gaussian signals that are poorly parametrized by the bispectrum (the three-point function). Such non-Gaussian deformations of the statistics may be crucial to understand the generation of primordial black holes, and necessarily require...
I will review the status of the dark matter theory and phenomenology.
Future generations of galaxy redshift surveys will sample the large-scale structure of the Universe over unprecedented volumes with high-density tracers, allowing for precise measurements of the clustering statistics. In order to properly exploit the full potential of such data, a robust likelihood pipeline is required, starting with an accurate theoretical prediction of cosmological...
Boson-stars are self-gravitating Bose-Einstein condensates of ultra-light boson fields, which are widely considered as strong candidates to account for at least part of Dark Matter. Boson-star mergers can produce gravitational-wave signals observable by current detectors such as Advanced LIGO and Virgo. I will present a systematic comparison of existing (high-mass) gravitational-wave signals...
We study the spherical collapse of non-top-hat matter fluctuations in the presence of dark energy with arbitrary sound speed ($c_s$). The model is described by a system of partial differential equations solved using a pseudo-spectral method with collocation points. This method can reproduce the known analytical solutions in the linear regime with an accuracy better than $10^{-6}$ % and better...
The Gibbons-Maeda-Garfinkle-Horowitz-Strominger (GMGHS)
black hole is an influential solution of the low energy heterotic
string theory. As it is well known, it presents a singular extremal
limit. We construct a regular extension of the GMGHS extremal black
hole in a model with $\mathcal{O}(\alpha')$ corrections in the action,
by solving the fully non-linear equations of motion....
In this talk I will present the formulation of the Effective Field Theory (EFT) of black hole perturbations within scalar-tensor theories on an inhomogeneous background. In particular, the EFT is constructed while keeping a background of a scalar field to be timelike, which spontaneously breaks the time diffeomorphism. I will then discuss a set of consistency relations that are imposed by the...
I will introduce a fast and complementary approach to study galaxy rotation curves directly from the sample data, instead of first performing individual rotation curve fits. The method is based on a dimensionless difference between the observational rotation curve and the expected one from the baryonic matter ($\delta V^2$). It is named as Normalized Additional Velocity (NAV). Using 153...
Superconducting nanowires, a mature technology originally developed for quantum sensing, can be used as a target and sensor with which to search for dark matter interactions with electrons. We leverage recent developments in the theory of dark matter interactions in dielectrics to robustly predict the event rate in a nanowire device, fully accounting for the many-body physics of the detector....
The standard cosmological model, namely the flat LCDM model, has been tremendously successful in describing cosmological observations for over two decades. Still, it suffers from theoretical caveats, in addition to recent problems like the SH0ES tension between H0 measurements from the early- and late-time Universe. In light of these issues, I will show results of some null tests of...
The Euclid space-based survey will observe and map the distribution of galaxies with unprecedented accuracy, allowing us to improve the knowledge of the Universe and its dynamics as well as the nature of the so-called dark matter that contributes up to a quarter of the total energy density of the Universe. Furthermore, key research will involve the measurements of the subtle features produced...
The evidence for dark matter is overwhelming, yet there has not been an unambiguous detection of a dark matter particle. The XENON collaboration has operated successively larger experiments in the hunt for WIMP-dark matter using dual phase time projection chambers with xenon as the target material. The XENON collaboration is one of the leading collaborations in constraining the WIMP-nucleon...
We test the usual hypothesis that the Cosmic Microwave Background (CMB) dipole, its largest anisotropy, is due to our peculiar velocity with respect to the Hubble flow by measuring independently the Doppler and aberration effects on the CMB using Planck 2018 data. We remove the spurious contributions from the conversion of intensity into temperature and arrive at measurements which are...
A kinetic coupling between the photon and a dark photon, a massless U(1)-gauge boson in the dark sector, transfers dark photon’s birefringence to observed cosmic birefringence. Regardless of the origin of the dark birefringence, the amplitude and unique frequency-dependence of the cosmic birefringence depend on the kinetic-coupling constant and the dark-photon temperature. To explain the...
Dark matter not only provides the invisible scaffolding from which the birth of galaxies takes place, but by studying its distribution in our Universe we can infer a great deal of information regarding the growth of structure and cosmic expansion. Measuring the gravitational lensing of the CMB allows the mapping of all the matter distribution (for which the majority is dark matter) to very...
Em 1922 o matemático russo Alexander Friedmann publicou o artigo em que pela primeira vez na história se evocava a possibilidade que o universo fosse dinâmico e pudesse estar em expansão. A expansão do universo seria pouco depois confirmada pelas observações. Desse momento em diante, o moderno modelo cosmológico foi sendo paulatinamente construído. Hoje ele se alicerça sobre vários sólidos...
The Euclid survey will map the large scale structure with the aim of measuring the parameters of the standard cosmological model with unprecedented precision.
However, the great sensitivity of Euclid can also be exploited to test the most fundamental assumptions at the basis of the standard cosmological model. Here we present two works of the Euclid Consortium where, forecasts from Euclid...
The J-PAS (Javalambre Physics of the Accelerating Universe Astrophysical Survey) scans the sky through 56 narrow band (~140 Å) + 3 broad band optical filters that render a R~50 spectra of every object detected in the footprint. The first square degree covered by the miniJPAS survey has produced \sigma_{NMAD}<0.005 x (1+z) for most galaxies with r<22.5, thus enabling an accurate reconstruction...
Primordial Black Holes (PBHs), first postulated more than half a century ago, remain an active and fascinating area of research and provide an exciting prospect for accounting for Dark Matter. In this talk I will discuss the possibilities for production of PBHs near to Dark Matter mass scales from realistic multi-field inflation models that arise naturally from supergravity. These models fit...
Through their observable properties, the first and smallest dark matter halos represent a rare probe of subkiloparsec-scale variations in the density of the early Universe. These density variations could hold clues to the nature of inflation, the postinflationary cosmic history, and the identity of dark matter. The first halos are understood to possess a uniquely compact central mass...
The production of dark relics from the decay of the primordial inflaton condensate must always be considered when building models of the very early Universe. Even in the absence of direct couplings, dark matter and radiation can be produced from the gravitational interaction between the dark and inflaton sectors. In this talk I will discuss the non-equilibrated production of scalar dark matter...
In this work we analyze the stability criteria in $f(R)$ theories of gravity in the metric formalism under the approach of a thermodynamics analogy proposed in [C.D. Peralta and S.E. Jorás JCAP06(2020)053] for $\phi^4$ and double well inflationary potentials. We starting from the mentioned potentials in the Einstein frame, and obtain a parametric form of $f(R)$ in the corresponding Jordan...
We discuss compact stars consisting of cold quark matter and fermionic dark matter treated as two admixed fluids. After the computation of the stellar structure and fundamental radial oscillation frequencies for different masses of the dark fermion in the cases of weak and strong self-interacting dark matter, we show that the fundamental frequency can be dramatically modified and, in some...
We study the E and B mode polarisation of the cosmic microwave background (CMB) originating from the transverse peculiar velocity of free electrons during reionisation and post reionisation era. Interestingly, apart from having a blackbody part, the spectrum also contains a Sunyaev Zel'dovich (SZ) type (y-type) distortion, which makes it distinguishable from primordial polarisation as well as...
We address the issue of black hole scalarization and its compatibility with cosmic inflation and big bang cosmology from an effective field theory (EFT) point of view. In practice, using a well-defined and healthy toy model which (in part) has been broadly considered in the literature, we consider how higher-order theories of gravity, up to cubic operators in Riemann curvature, fit within this...
The detection of non-Gaussianity in primordial perturbations offers monumental new information about the early Universe. All models of inflation predict at least some level of primordial non-Gaussianity, and many models result in potentially observable non-Gaussian signatures. While detection efforts thus far have not found any significant primordial non-Gaussianity, they are not sensitive to...
We propose a new solution to explain the anomalous absorption feature detected by the EDGES collaboration in the 50-100 MHz range, using a new millicharged dark matter model, taking into account the existing cosmological and astrophysical constraints. We predict new unique signals to test our dark matter model with future cosmological surveys.
The generation of non-Gaussianity during inflation is often viewed in the context of perturbative processes producing small amounts of non-Gaussianity correlated with an underlying Gaussian field. However, there exist physical mechanisms by which non-Gaussianity can be produced non-perturbatively and in novel forms which are poorly modeled by the data templates used in current analysis. We...
Microlensing of extragalactic sources, in particular the probability of significant amplifications, is a potentially powerful probe of the abundance of compact objects outside the halo of the Milky Way. Accurate experimental constraints require an equally accurate theoretical model for the amplification statistics produced by such a population. In this article, we argue that the simplest...
The big open questions we still have currently in the fields of gravitation and cosmology, such as the dark matter and dark energy problems, among other reasons, have led to the development of many modified theories of gravity. These theories need to be tested in various scenarios to see whether they solve the problems they try to solve. Neutron stars are one of the best astrophysical...
In the late 90’s, Reiss et al. [1] and Perlmutter at al. [2] by taking the Supernovae 1a independently proved that the universe is passing through an accelerated expansion. Many observations have supported this accelerated expansion of the late time universe [1,2,3,4,5]. The biggest mystery in the early universe is the production of excess of matter over antimatter [6,7,8. The present study...
Neural nets have become popular to accelerate parameter inferences, especially for the upcoming generation of galaxy surveys in cosmology. As neural nets are approximative by nature, a recurrent question has been how to propagate the neural net’s approximation error, in order to avoid biases in the parameter inference. We present a Bayesian solution to propagating a neural net’s approximation...
In the framework of the Brans-Dicke scalar-tensor theory of gravitation, we investigate the role of a self-interacting fermionic field in an FLRW universe filled with dust and radiation constituents. This model is shown to present a variety of qualitative behaviors, depending on the numerical parameters chosen. In particular, we find that the fermionic field is capable of promoting a...
Intrinsic alignment (IA) modelling and photometric redshift estimation are two of the main sources of systematic uncertainty in weak lensing surveys. We investigate the impact of redshift errors when using different IA models. We show that both errors on the mean of the redshift bin $\delta_z$ and errors of the width of the redshift bin $\sigma_z$ can lead to biases in cosmological...
As numerical complexities of cosmological models are increasing in recent years, so too are the demands for resources when computing solutions to the Einstein-Boltzmann equations with codes like \textsc{class} and \textsc{camb}. A solution to this demand is, of course, more computational power through increasingly better and faster hardware, but perhaps another and more sustainable approach is...
We studied the four models implemented in PYTHIA8 for the production of dark matter or associated particles at the LHC based on the simplest extensions of the Standard Model. The first model includes dark matter production via s-channel mediators. This includes production in association with a jet for a vector boson or scalar mediator. Aside from the standard simplified models where the dark...
Primordial black hole (PBH) has come up as a very promising cold dark matter candidate in recent years. The signature of PBHs in the gravitational wave background is expected as PBH formation requires a large amplfication in inflationary scalar curvature perturbation, which sources the tensor perturbation in second-order and leads to a detectable amplification in the gravitational wave (GW)...
It is interesting to know whether or not we can determine black-hole's parameters such as the mass, spin, inclination angle, and distance only from the information of black-hole's shadow. In this work, assuming a non-spinning black hole, i.e., a Schwarzschild black hole, with an infinitely thin accretion disc for simplicity, we show that the system's parameters such as the angular...
Oscillons are localized field configurations oscillating in time with lifetimes orders of magnitude longer than their oscillation period. This talk shows the deformation of one-dimensional breather solutions of the sine-Gordon (SG) equation into oscillons. SG equation is deformed by a radial damping term present in the d-dimensional Laplacian. Oscillons are evaluated (a) in a regime of...
We consider an extension of the novel 4D Einstein-Gauss-Bonnet (EGB) gravity by proposing a coupling between the scalar field and the Gauss-Bonnet term, which is otherwise absent in the novel 4D EGB theory, and demonstrate that the additional contributions to the equations of motion come from both the scaling of a coupling constant and the non-minimal coupling between the scalar field and...
Several physical systems of interest in cosmology, such as the Lovelock extension of general relativity in higher dimensions, k-essence fields, Horndeski theories, and nonlinear electrodynamics, have apparent ill-defined sympletic structures, due to the fact that their Hamiltonians are multivalued functions of the momenta. In this talk, based on the paper [PRD 105, 084064 (2022)], the...
We consider a minimally massless coupled quantum scalar field with an asymmetric (quartic plus cubic) self interaction, V (φ) = λφ^4/4!+βφ^3/3! in the (3 + 1)-dimensional inflationary de Sitter background. This potential is bounded from below regardless the sign of β. The motivation of this study comes from the fact that such a potential may generate negative vacuum expectation value of V(φ)...
Early dark energy (EDE) alleviates the H_0 tension at the cost of increasing the clustering amplitude and worsening the $S_8$ discrepancy. Motivated by massive neutrinos' ability to suppress structure, we study their impact on EDE combining Planck and BOSS full-shape clustering data. A Bayesian analysis returns no evidence for a non-zero neutrino mass sum $M_{\nu}$ ($<0.15,{\rm eV}$ at...
Demanding the validity of the Generalized Second Law implies the existence of entropy bounds. By considering the absorption of matter from arbitrarily close to the horizon, Bekenstein and collaborators derived a universal entropy bound valid for any charged, rotating distribution of matter (including the Kerr-Newman black hole); and, based on the no-hair conjecture, argued that this bound...
In this talk I will show how the Expansion Lensing relationship d_L=d_A(1+z) is derived from the Friedmann-Lemaître-Robertson-Walker (FLRW) metric. The expression also follows from the fact that the angular distance of a galaxy (d_A=S/theta), i.e. the distance at emission, is defined identically for both static and expanding universes, and hence both images subtend the same angle theta....
By choosing a suitable set of cosmological parameters, one can classify them into two groups with respect to their impact on the linear matter power spectrum $P_\mathrm{L}(k)$ when it is expressed in Mpc units: the evolution parameters, $\Theta_\mathrm{e}$, which determine its amplitude at a given redshift and the shape parameters, $\Theta_\mathrm{s}$, which only affect its shape. This...
Fast Radio Bursts (FRBs) are a relatively recent discovered object in cosmology and astrophysics, whose origin is still an open problem. They are a class of brief ($\sim$ ms) and bright ($\sim$ Jy) radio transients that have been detected by a number of radio telescopes around the globe. There is a new generation of radio telescopes coming online, such as the BINGO, CHIME, SKA and others,...
In order to prepare for the upcoming wide-field cosmological surveys, large simulations of the
Universe with realistic galaxy populations are required. In particular, the tendency of galaxies
to naturally align towards overdensities, an effect called intrinsic alignments (IA), can be a
major source of systematics in the weak lensing analysis. As the details of galaxy formation
and...
At scales of dozens of Mpcs, the galaxy distribution forms the cosmic web. Galaxy clusters occupy its nodes and are connected to other nodes by vast filamentary chains of galaxies and groups of galaxies. In this work we are investigating some nearby superclusters and filaments in the southern skies. We use the high-precision photometric redshifts obtained in the 12 band S-PLUS photometric...
In this work, we generalize to a viable Horndeski theory of gravity, the most general scalar-tensor theory that has second-order field equations in four dimensions, the expression of a statistically homogeneous and unpolarized stochastic gravitational wave background signal measured as the correlation between the individual signals detected by two not coincident and not coaligned GW...
Astrochemistry plays an important role in the most of astrophysical processes on all stages of the universe life. Unfortunately, the most of the chemical processes can't be simulated in labs because of the physical conditions. We will show our latest high-performance computing code for numerical simulation of astrochemical problems. This code can be used as standalone application for...
The well-known small-scale discrepancies between the observed satellite abundance in the Local Group and predictions from Cosmological simulations in CDM seems to point to missing physics in our models. This new physics may be a different dark matter nature beyond the standard WIMP candidate. In my talk I will discuss how the internal structure and increasing discoveries of fainter galaxies...
We present a joint analysis of the power spectra of the Planck Compton y-parameter map and the projected galaxy density field using the WISE all-sky survey. We detect the statistical correlation between WISE and Planck data (gy) with a significance of 21.8σ. We also measure the auto-correlation spectrum for the tSZ (yy) and the galaxy density field maps (gg) with a significance of 150σ and...
Magnetic fields present in the Universe and interactions with the cosmic radiation backgrounds play an important role shaping the flux of the ultrahigh energy cosmic rays. To account for both processes we include in the SimProp cosmic ray propagation code a routine to follow the direction of propagation of the particles in a turbulent magnetic field. We compute thus the modification of the...
We study the tunneling probability of a massive ($m_w$) uncharged scalar packet out from a near-extremal, static charged black hole (with mass $M$ and charge $Q \to M^+$). We show that there is indeed a \textit{net} probability that a massive uncharged particle tunnels out from the black hole so that the final state (with new mass $M'\equiv M-m_w < Q$) does violate the cosmic censorship...
Oscillons are oscillating, localized configurations in real scalar field theories. They appear in potentials that are shallower than quadratic away from the minimum and can be extremely long-lived.
Since plateau models are of great relevance for inflation, oscillons have been shown to form efficiently during preheating in a wide range of such models. Their formation and decay are...
Artificial neural networks can model nonlinear relationships in datasets. In observational cosmology there are many situations involving complex datasets, therefore in this talk we present some applications of neural networks in the framework of cosmological data analysis. We use observational data and numerical simulations; the tasks we have tackled with neural networks have been...
Dynamical system formulation is an important qualitative tool now widely used in
cosmology to understand the cosmological solution space of a theory. A number of
dynamical system formulations have been proposed over the last few years to analyse
cosmological solutions in f(R) gravity. I will try to give a brief introduction to the
di↵erent approaches, presenting them in a chronological...
When generalized noncommutative Heisenberg algebra accommodating gravitational field as specified by string theory, for instance, is thoughtfully applied on Finsler manifold, the quantized metric tensor could be defined. By constructing the affine connections on pseudo--Riemannian manifold, quantization of Riemann curvature tensor and its unique contractions, Ricci curvature tensor and scalar,...
Astrophysical observations are largely based on electromagnetic signals still read with the Maxwellian massless and linear theory, possibly an approximation of a larger theory, as Newtonian gravity is for Einsteinian gravity in weak fields. Photons are the sole free massless particles in the Standard-Model (SM). Apart from massive formalisms (de Broglie-Proca, Bopp, Stueckelberg and others),...
Black Holes with masses of the order of $10^{14}$g would be evaporating today, which could have been formed in the beginning of the universe. On the other hand, Fast Radio Bursts are thought to be associated to compact objects with extreme magnetic fields. Starting from V. Manko's solution of the Einstein Equations for a Rotating Black Hole with a magnetic field, it's emission properties are...
The problems with the stantard model of cosmology $\Lambda$CDM are well-known, such as the origin and behaviour of Dark Matter and Dark Energy or some tensions with the inferred value of some parameters when using distinct data sets, and several solutions have been proposed. One approach to try and elucidate the nature of the Dark Energy and relieve the parameter tensions is through...
Spectroscopic redshifts ($z$) are obtained through the spectra of astronomical objects, this process is time-consuming, expensive, and frequently impossible for large numbers of galaxies due to telescope time limitations. Thus, in order to find this parameter $z$, in this work, we use the photometry of galaxies to determine this same quantity. Photometric redshifts can be evaluated through the...
In the first stages of inflationary reheating, the mean energy of the radiation produced by inflaton decay is higher than the commonly defined reheating temperature. In thermal equilibrium, particle production can then be significantly enhanced relative to the subsequent radiation dominated era. Furthermore, in the earliest stages of reheating, before thermalization takes place, scattering of...
All models of inflation predict some non-Gaussian signatures in the cosmological distribution of energy, the search for which is a subject of great importance to our understanding of the early universe. In this work, we present simulated sky maps for a novel extended stochastic inflation model that is motivated by an ambitious suite of high-accuracy lattice simulations of early-universe field...
The inflationary origin of primordial black holes (PBHs) relies on a large enhancement of the power spectrum of the curvature fluctuation ζ at wavelengths much shorter than those of the CMB anisotropies. Quantum gravity inspired models are characterized by moduli spaces with highly curved geometries and a large number of scalar fields that could vigorously interact with ζ (as in the...
The Cosmology Large Angular Scale Surveyor (CLASS) is a set of four ground-based telescopes designed to measure and characterize the polarization signal of the cosmic microwave background (CMB) on the largest angular scales in order to probe the epochs of inflation and reionization. Located in a high-altitude site in the Atacama Desert, CLASS covers 70% of the sky in frequency bands centered...
The observation of neutrino flavor oscillations by various experiments involving both natural (solar and atmospheric) and man-made (accelerators and reactors) neutrino sources firmly indicates that neutrinos are massive particles.
In fact, all these experiments can be well understood if we assume the so-called {\it Standard Paradigm} that is, that the three known neutrino interaction...
The particle concept in curved space-time is, in general, observer de-
pendent, as is well-known from the Unruh effect. This, in particular, is
really important to understand the particle emission from black holes. In
this work, we study the Unruh effect under the perspective of De Broglie-
Bohm interpretation of quantum mechanics, where from the wave func-
tional we obtain the associated...
