The striking discovery that the Cosmic expansion is accelerating has turned into one of the puzzles in Cosmology sparking large observational campaigns to map the geometry and the large-scale structure of the Universe across cosmic time. I will review this effort and then discuss The Dark Energy Survey (DES), a state-of-the-art galaxy survey designed to map the positions and shapes for 300...
I will provide a new interpretation for the Bayes factor combination used in the DES first year analysis to quantify the tension between the Dark Energy Survey (DES) and Planck datasets. The ratio quantifies a Bayesian confidence in our ability to combine the datasets. This interpretation is prior-dependent, with wider prior widths boosting the confidence. I therefore propose that if there are...
The current data favour metastability of the electroweak (EW) vacuum, which poses a number of cosmological challenges. We suggest a novel solution which does not employ any extra fields beyond the inflaton. We show that the Higgs mixing with an inflaton can lead to a stable EW vacuum. A trilinear Higgs–inflaton coupling always results in such a mixing and it is generally present in realistic...
Unified Dark Matter models (UDM), a class of models that entertains the possibility of a universe where dark matter and dark energy exist as a single fluid, are an alternative approach to ${{slash}}Lambda$CDM. In this work we focus on a model with a fast transition between dark matter-like and dark energy-like behaviours. We have tested this UDM model against SNe Ia, BAO, CMB and weak lensing...
In this talk we explore the consequences of inferring cosmological parameters with uncertain theory predictions in which we include potential biases and noise sources. We will discuss that noise sources in the theory prediction translate into scatter noise in the likelihood and will provide an estimation of this quantity. We will show issues that might appear if trying to estimate parameters...
One of the fundamental assumptions of the standard LCDM cosmology is that, on large scales, all the matter-energy components of the Universe share a common rest frame. This seems natural for the visible sector, that has been in thermal contact and tightly coupled in the primeval Universe. The dark sector, on the other hand, does not have any non-gravitational interaction known to date and...
I will review the present status of the search for primordial black holes as the main component of dark matter and will describe future prospects.
One of the most mysterious and abundant components of the current known universe is the so called Dark Matter. While we usually resort to physics beyond the Standard Model and new particles as possible explanations for it, we may not need to do so at all. Black Holes formed during or after inflation (thus "primordial") could end up being the majority of the Dark matter, thus solving the issue...
Galaxy Surveys provide an important cosmological probe to study dark energy and structure formation in the Universe. The cosmological content is however encoded in biased tracers of the non-linear evolved cosmic density field. The analysis of such data is complex and requires non-Gaussian posterior distribution functions (PDFs). Sampling such PDFs can be done within a Bayesian framework at the...
Pre-recombination physics imprinted the Baryon Acoustic Oscillation (BAO) feature on the matter distribution and therefore on the galaxy statistics we observe today. This known-size BAO scale let cosmological surveys study the accelerated expansion of the Universe and the unknown component that generates it. Present surveys make use of 2-point correlations function to study galaxy distribution...
We study the viability of the detection of the primordial polarization B-mode of the cosmic microwave background (CMB) from the ground, but operating on the microwave low-frequency range (e.g., from 10GHz-120GHz). The reason to choose this frequency range is twofold: one the one hand, the instrumental costing is, in principle, lower than at higher frequencies and, on the other hand, it could...
We present a new determination of the evolving spectral energy distribution of the Extragalactic Background Light (EBL) purely based on galaxy data. Our calculations use multiwavelength observations from the ultraviolet to the far-infrared (far-IR) of a sample of aproximately 150,000 galaxies detected up to z~6 from the five fields of the Cosmic Assembly Near-Infrarred Deep Extragalactic...
We briefly review the general insight into the indirect searches of dark matter. In particular, we focus on the multi-TeV dark matter candidate among other weak interactive massive particles. We present both the state-of-the-art on this sub-eld and recent sensitivity analyses for the Square Kilometer Array (SKA) and the Cerenkov Telescope Array (CTA). We discuss the model independent approach...
We are in the middle of a pause. While we ponder the results of the Planck mission and a host of probes of large scale structure, and while we wait for a host of new larhe scale surveys - Euclid, LSST, DESI, to name a few - we can take stock of where we are in our understanding of the late time evolution of the Universe. I will discuss where we are in terms of theory and talk about a few of...
The Cosmological Principle is applied to a 5D Ricci-flat (bulk) manifold. The general solution is given explicitly in the form of a single metric, namely ‘M-metric’, for every sign of the space curvature, both in the 4+1 and the 3+2 case. Friedmann-Robertson-Walker (FRW) metrics are obtained by projecting the ‘mother’ M-metric onto specific 3+1 (brane) hypersurfaces (top-down approach). This...
It has been shown that the longitudinal mode of a massive vector boson can be produced by inflationary fluctuations and account for the dark matter content of the Universe. In this work we examine the possibility of instead producing the transverse mode via the coupling ϕFF̃ between the inflaton and the vector field strength. Such a coupling leads to a tachyonic instability and exponential...
One possible and natural derivation from the collisionless cold dark matter (CDM) standard cosmological framework is the assumption of the existence of interactions between dark matter (DM) and photons or neutrinos. Such interacting DM models would imply a suppression of small-scale structures due to a large collisional damping effect and can help alleviate alleged tensions between standard...
In this talk, we present Cherenkov Telescope Array (CTA) prospects for WIMP dark matter (DM) indirect detection through very-high-energy gamma rays originated from DM annihilations in low-mass Galactic DM subhalos. Given their masses, these are not expected to host gas/stars at all and would thus appear in the sky as unidentified gamma-ray sources (unIDs). By using the latest instrumental...
The Planck Mission from ESA has recently provided the best available full-sky intensity and polarization CMB data, covering a range of frequencies from 30 to 857 GHz. In this talk I will give an overview of the main Planck legacy results, which currently provide our strongest constraints on the parameters of the standard cosmological model. I will also briefly review the current and future...
We propose a novel scenario for the detection of radio signals from axionic halo dark matter. Axions or axion-like particles produce radio waves via spontaneous decay into two photons. In addition, stimulated emission by a background containing photons of identical wavelength enhances the rate of photon emission by axionic decay. A photon background generated by a bright radio source should...
The PAU Survey (PAUS) is an imaging survey using a 40 narrow-band filter camera, named PAUCam. Images obtained with the PAUCam suffer from scattered light: an optical effect where light appears where it is not intended to be. Scattered light is not a random effect, it can be predicted and corrected for. Nevertheless, currently, around 8% of the PAUS flux measurements are flagged as scattered...
Cosmic voids gravitationally lens the cosmic microwave background (CMB) radiation, resulting in a distinct imprint on degree scales. We aimed to probe the consistency of simulated ΛCDM estimates and observed imprints of voids identified in the first year data set of the Dark Energy Survey (DES Y1). In particular, we intended to explore other aspects of the previously reported excess integrated...
Total density of the Universe is very close to the critical density; that is, the matter-energy content is exactly that required in the Universe to be flat. This strange coincidence ('flatness problem') has not yet been explained, as well as the nature of dark energy, which compensates the gavitational force caused by the matter. To explain the origin of the dark energy, this works uses a...
Using the formalism of quantum field theory in curved spacetimes, we study semiclassical effects in geometries which get close to the formation of an event horizon. These geometries are such that they imprint special features on the quantum vacuum of the fields. Specifically, we will present a series of asymptotically flat, spherically symmetric spacetimes which get close to the formation of a...
In this talk I will make a sort review on alternative theories of gravity with torsion along with a brief statement for their motivation. Then, I will focus my speech on Lagrangian densities quadratic in the curvature and torsion tensors, as they are known to produce a dynamic torsion field. By assuming that General Relativity should be recovered when the torsion vanishes and investigating the...
Regardless of the precise nature of dark matter (DM), its distribution in the central regions of galaxies remains poorly constrained at present. In particular, DM halos may be significantly affected by the presence of central supermassive black holes, leading to the possible formation of high density spikes. Two objects are of particular interest in this context: Sgr A* at the center of the...
The Cosmic Microwave Background (CMB) temperature and polarization anisotropy measurements from the Planck mission have provided a strong confirmation of the LCDM model of structure formation. However, there are a few interesting tensions with other cosmological probes that leave the door open to possible extensions to LCDM. I will review some extended cosmological scenarios, in order to find...
In this work, we explore the possibility of topological defects as viable dark matter candidates. The non-thermal production of magnetic monopoles by a phase transition is studied. The Kibble mechanism is analyzed, concluding that it is not a good approach to estimate their abundance and studying the corrections of the Kibble-Zurek model. We also study the effect of monopoles annihilation...
In flat spacetime, an instability problem arises in the homogeneous field configuration of a system with concave potential. We extend that analysis to an accelerated expanding universe where the potential is not needed to be concave in order to have instabilities. We study the particular case of an inflationary universe with a slow-roll phase and calculate the lifetime associated to its decay....
In warm inflation, substantial radiation production can occur concurrently with the inflationary expansion. In the strong dissipative regime, the temperature dependent dissipative coefficient leads to the wrong spectral index. An imperfect radiation fluid, via shear effects, can successfully solve that problem, although one needs to resort to weakly interacting fluids. However, certain...
In this talk I will present a new modified theory of gravitation, that includes infinite derivatives and torsion in the action. I shall also provide some solutions that are ghost and singularity free.
In this talk we shall consider the possibility of chiral symmetry restoration for observers located close to acceleration horizons, black holes and cosmological horizons. The Thermalization Theorem formalism and the large N limit (with N being the number of pions) will be employed to solve the lowest-order approximation to QCD at low energies in Rindler spacetime and close to the horizons of...
Although the Lambda cold dark matter model (ΛCDM) has become the best phenomenological description for the late-time accelerating phase of the Universe, the yet unsolved cosmological constant problem has driven an effort towards alternatives. We will mention two leading approaches which avoid the introduction of a cosmological constant. On the one hand, Dark Energy (DE) models where yet...
I will briefly outline the first progresses with miniJPAS, the JPAS-like data obtained with the Pathfinder camera attached to the JST/T250 telescope at the OAJ. This small data set already encodes all the richness and complexity to be expected for regular J-PAS data, and allows defining the hottest science cases to be addressed with the main survey. I will also describe the strategy for J-PAS...
The next generation of galaxy surveys will allow us to test one of the most fundamental assumptions of the standard cosmology, i.e., that gravity is governed by the general theory of relativity (GR). In this paper we investigate the ability of the Javalambre Physics of the Accelerating Universe Astrophysical Survey (J-PAS) to constrain GR and its extensions. Based on the J-PAS information on...
We compare the statistics and morphology of arcs in galaxy clusters using simulations with standard cold dark matter and simulations where dark matter has a probability of interaction (parametrized by its cross section), i.e self-interacting dark matter. Through ray tracing, we produce a statistically large number of arcs around galaxy clusters at different redshifts. Since dark matter in more...
Dark matter, as a cold collisionless fuid, effectively occupies a three-dimensional sub-manifold in six-dimensional phase space. In simulations, this "dark matter sheet" can in principle be reconstructed by interpolation techniques to obtain an almost exact density estimate. However, in regions of strong mixing (like dark matter haloes), this is difficult due to the rapid growth of the sheet's...
We study the dependence of a variety of halo properties (shape, spin, virialisation status) on different environments in a whole-sky ΛCDM light-cone halo catalogue extending to z ∼ 0.65,CDM light-cone halo catalogue extending to z ∼ 0.65, 0.65, using a simple and well-defined halo isolation criterion. Using this definition of the environment we study if and how the DM halo-properties and their...
If dark matter particles annihilate, then we should detect signals of this annihilation in the sky. In this talk we will focus on the contribution of particle dark matter in the injection of cosmic rays in dwarf spheroidals and the synchrotron emission from secondary processes. We also study the Square Kilometre Array (SKA) sensitivity in the detection of dark matter candidates that would fit...
I employ methods of fractal geometry and fluid turbulence to describe how the cosmic web structure arises in the nonlinear regime of evolution of the LCDM cosmology. I evaluate this theory with the results of N-body simulations and observations of the galaxy distribution by the Sloan Digital Sky Survey.
A generic modified gravity theory, that generates a dynamical dark energy, will produce a different evolution at the background level, determined by the DE equation of state, as well as different cosmological perturbations with respect to LCDM. An effect that is completely general to modified gravity models is that the propagation of tensor perturbations is modified so that it emerges a notion...
The PAU Survey (PAUS) is an innovative photometric survey with 40 narrow bands at the William Herschel Telescope (WHT). The narrow bands are spaced at 100A intervals covering the range 4500A to 8500A and, in combination with standard broad bands, enable excellent redshift precision. Using BCNz2, a new photometric redshift code developed for this purpose, we characterise the photometric...
In this work we have considered the gravitational production as the mechanism responsible for the creation of dark matter during the early epochs of the Universe. This mechanism imposes some constrains in the parameter space of the candidate field as it abundance is bounded by the observations. We have considered the dark matter field as a scalar one not minimally coupled to gravity. The...
I will summarize the progress on image simulations on LSST-DESC and their relevance for next generation cosmological surveys.
Strong lenses are systems in which the light from a background source is deflected by a foreground galaxy or group of galaxies, resulting in multiple images of the background source. These images are also usually heavily distorted, acquiring the shape of rings or arcs. Study of these images provides us unique information about the distribution of matter (baryonic plus dark) within the...
The late time acceleration of the Universe can be characterized in terms of an extra, time dependent, component of the universe -- dark energy. The simplest proposal for dark energy is quintessence, a scalar field, phi, whose dynamics is solely dictated by its potential, V(phi). In this simple case, just an extra function of the background is necessary to describe the evolution of the dark...
The late time acceleration of the Universe can be characterized in terms of an extra, time dependent, component of the universe -- dark energy. The simplest proposal for dark energy is quintessence, a scalar field, phi, whose dynamics is solely dictated by its potential, V(phi). In this simple case, just an extra function of the background is necessary to describe the evolution of the dark...
Galaxy clustering is one of the main cosmological probes used by the Dark Energy Survey to investigate the nature of the Dark Energy. In order to avoid biasing our measurements derived from galaxy clustering, the impact of observing conditions must be taken into account, since they can imprint a non-cosmological clustering signal. These observing conditions are characterized through the...
The QUIJOTE (Q U I JOint TEnerife) CMB Experiment operates from the Teide Observatory, providing a novel view of the northern sky in the frequency range from 10 to 20 GHz with the Multi Frequency Instrument (MFI). Moreover, it is targeting the detection of the B-modes in the polarization of the CMB at 30 and 40 GHz with the Thirty-Forty GHz Instrument (TFGI), with a tensor to scalar ratio goal...
The nature of dark matter (DM) is still an open question for modern physics. In the particle DM paradigm, this elusive kind of matter cannot be made of any of the known particles of the Standard Model (SM). Many efforts have been made in order to model the nature of the DM. Among others, and beyond the SM of particle physics, we focus on brane world theory as a prospective framework for DM...
In this talk, we present our studies of the discovery potential of low-mass Galactic dark matter (DM) subhalos for indirect searches of DM. In particular, we analyzed the properties of DM halo substructure in a galaxy like our own. To do so, we have used data from the Via Lactea II (VL-II) N-body cosmological simulation, that resolves subhalos down to one million solar masses. First, we...
As high redshift galaxies cannot be resolved, it is necessary to have the information of the whole stellar population in order to interpret correctly the data. Thus, templates of spectra of simple stellar populations (SSPs) are needed to extract information about the stellar populations. We present our new high resolution spectra of SSPs. We have tested the application of the spectra testing...
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...
