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In this work, we constrain the Hubble constant parameter, $H_0$, using a combination of the Pantheon sample and galaxy clusters (GC) measurements from minimal cosmological assumptions. Assuming the validity of the cosmic distance duality relation, an estimator is created for $H_0$ that only depends on simple geometrical distances, which is evaluated from Pantheon and a GC angular diameter distance sample afterward. The statistical and systematic errors in GC measurements are summed in quadrature in our analysis. We find $H_0 = 67.22 \pm 6.07$ ${\rm km \ s^{-1} Mpc^{-1}}$ in $1\sigma$ confidence level (C.L.). This measurement presents an error of around 9\%, showing that future and better GC measurements can shed light on the current Hubble tension, Comment: 8 pages, two figures

The possible time variation of the fundamental constants of nature has been an active subject of research since the large-number hypothesis was proposed by Dirac. In this paper, we propose a new method to investigate a possible time variation of the speed of light ($c$) along with the fine-structure constant ($\alpha$) using Strong Gravitational Lensing (SGL) and Type Ia Supernovae (SNe Ia) observations. We assume a general approach to describe the mass distribution of lens-type galaxies, the one in favor of the power-law index model (PLAW). We also consider the runaway dilaton model to describe a possible time-variation of $\alpha$. In order to explore the results deeply, we split the SGL sample into five sub-samples according to the lens stellar velocity dispersion and three sub-samples according to lens redshift. The results suggest that it is reasonable to treat the systems separately, but no strong indication of varying $c$ was found., Comment: 10 Pages, 4 Figures, and 1 Table. Published in JCAP

Motivated by future gravitational waves observations, we perform forecasts analysis to constrain a possible time variation of the fine structure constant ($\alpha$) within the context of the so-called runaway dilaton model. For this purpose, some gravitational-wave standard sirens mock data within the perspective of Einstein Telescope and LISA mission were considered jointly with current strong gravitational lensing systems observations. We find that future standard sirens observations can also play an important role in the search for possible variations of $\alpha$ within the methodology presented in this work., Comment: Accepted version by the Astroparticle Physics

We establish new constraints on $f(T)$ gravity models by using cosmological data. In particular, we investigate the restrictions given by the gas mass fraction measurements of galaxy clusters and transversal BAO data. Both data sets are regarded as weakly dependent on a fiducial cosmology. In addition, we also include a CMB measurement of the temperature power spectrum first peak, along with $H(z)$ values from cosmic chronometers and supernovae data from the Pantheon data set. We also perform a forecast for future constraints on the deviation of $f(T)$ models from the $\Lambda$CDM scenario by following the specifications of the J-PAS and Euclid surveys and find significant improvements on the constraints of the $b$-parameter, when compared to the results of the statistical analysis., Comment: 19 pages, 4 figures, 3 tables

A new method based on large-scale structure observations is proposed to probe a possible time variation of the fine-structure constant ($\alpha$). Our analyses are based on time-delay of Strong Gravitational Lensing and Type Ia Supernovae observations. By considering a class of runaway dilaton models, where the cosmological evolution of the fine-structure constant is given by $\frac{\Delta \alpha}{\alpha} \approx -\gamma \ln{(1+z)}$, we obtain limits on the physical properties parameter of the model ($\gamma$) at the level $10^{-2}$ ($1\sigma$). Although our limits are less restrictive than those obtained by quasar spectroscopy, the approach presented here provides new bounds on the possibility of $\frac{\Delta \alpha}{\alpha} \neq 0$ at a different range of redshifts., Comment: 9 pages, 4 figures and 1 table - Accepted in The European Physical Journal C

In this paper, we present a unified scheme based on the fluid description of the dark sector of the universe. The scheme captures models with interaction between dark energy and dark matter, being the core of generalization the time-varying equation-of-state parameter $\omega(a)$ and the time-dependent interactions through the interaction function $\epsilon(a)$, where $a$ is the scale factor. Furthermore, we propose thermodynamics constraints on this generalized class of models using the laws of thermodynamics which are combined with observational data. In order to test the observational viability of the unified model, we perform a Bayesian analysis using cosmic chronometers, type Ia supernovae, cosmic microwave background, and angular baryon acoustic oscillation measurements., Comment: 9 pages, 4 figures, 2 tables. Version accepted for publication in EPJP

The Javalambre-Physics of the Accelerating Universe Astrophysical Survey (J-PAS) will soon start to scan thousands of square degrees of the northern extragalactic sky with a unique set of $56$ optical filters from a dedicated $2.55$m telescope, JST, at the Javalambre Astrophysical Observatory. Before the arrival of the final instrument (a 1.2 Gpixels, 4.2deg$^2$ field-of-view camera), the JST was equipped with an interim camera (JPAS-Pathfinder), composed of one CCD with a 0.3deg$^2$ field-of-view and resolution of 0.23 arcsec pixel$^{-1}$. To demonstrate the scientific potential of J-PAS, with the JPAS-Pathfinder camera we carried out a survey on the AEGIS field (along the Extended Groth Strip), dubbed miniJPAS. We observed a total of $\sim 1$ deg$^2$, with the $56$ J-PAS filters, which include $54$ narrow band (NB, $\rm{FWHM} \sim 145$Angstrom) and two broader filters extending to the UV and the near-infrared, complemented by the $u,g,r,i$ SDSS broad band (BB) filters. In this paper we present the miniJPAS data set, the details of the catalogues and data access, and illustrate the scientific potential of our multi-band data. The data surpass the target depths originally planned for J-PAS, reaching $\rm{mag}_{\rm {AB}}$ between $\sim 22$ and $23.5$ for the NB filters and up to $24$ for the BB filters ($5\sigma$ in a $3$~arcsec aperture). The miniJPAS primary catalogue contains more than $64,000$ sources extracted in the $r$ detection band with forced photometry in all other bands. We estimate the catalogue to be complete up to $r=23.6$ for point-like sources and up to $r=22.7$ for extended sources. Photometric redshifts reach subpercent precision for all sources up to $r=22.5$, and a precision of $\sim 0.3$% for about half of the sample. (Abridged), Comment: The miniJPAS data and associated value added catalogues are publicly accessible via this url: http://archive.cefca.es/catalogues/minijpas-pdr201912

Since there is no known symmetry in Nature that prevents a non-minimal coupling between the dark energy (DE) and cold dark matter (CDM) components, such a possibility constitutes an alternative to standard cosmology, with its theoretical and observational consequences being of great interest. In this paper we propose a new null test on the standard evolution of the dark sector based on the time dependence of the ratio between the CDM and DE energy densities which, in the standard $\Lambda$CDM scenario, scales necessarily as $a^{-3}$. We use the latest measurements of type Ia supernovae, cosmic chronometers and angular baryonic acoustic oscillations to reconstruct the expansion history using model-independent Machine Learning techniques, namely, the Linear Model formalism and Gaussian Processes. We find that while the standard evolution is consistent with the data at $3\sigma$ level, some deviations from the $\Lambda$CDM model are found at low redshifts, which may be associated with the current tension between local and global determinations of $H_0$., Comment: 15 pages, 12 figures

Physical limits on the equation-of-state (EoS) parameter of a dark energy component non-minimally coupled with the dark matter field are examined in light of the second law of thermodynamics and the positiveness of entropy. Such constraints are combined with observational data sets of type Ia supernovae, baryon acoustic oscillations and the angular acoustic scale of the cosmic microwave background to impose restrictions on the behaviour of the dark matter/dark energy interaction. Considering two EoS parameterisations of the type $w = w_0 + w_a\zeta(z)$, we derive a general expression for the evolution of the dark energy density and show that the combination of thermodynamic limits and observational data provide tight bounds on the $w_0 - w_a$ parameter space., Comment: 7 pages, 4 figures. Accepted for publication in European Physical Journal C

The analysis of perturbative quantities is a powerful tool to distinguish between different Dark Energy models and gravity theories degenerated at the background level. In this work, we generalise the integral solution of the matter density contrast for General Relativity gravity to a wide class of Modified Gravity (MG) theories. To calculate this solution is necessary prior knowledge of the Hubble rate, the density parameter at the present epoch ($\Omega_{m0}$) and the functional form of the effective Newton's constant that characterises the gravity theory. We estimate in a model-independent way the Hubble expansion rate by applying a non-parametric reconstruction method to model-independent cosmic chronometer data and high-$z$ quasar data. In order to compare our generalised solution of the matter density contrast, using the non-parametric reconstruction of $H(z)$ from observational data, with purely theoretical one, we choose a parameterisation of the Screened MG and the $\Omega_{m0}$ from WMAP-9 collaborations. Finally, we calculate the growth index for the analysed cases, finding very good agreement between theoretical values and the obtained ones using the approach presented in this work., Comment: 8 pages, 3 figures

The evolution of the X-ray emitting gas mass fraction ($f_{gas}$) in massive galaxy clusters can be used as an independent cosmological tool to probe the expansion history of the Universe. Its use, however, depends upon a crucial quantity, i.e., the depletion factor $\gamma$, which corresponds to the ratio by which $f_{gas}$ is depleted with respect to the universal baryonic mean. This quantity is not directly observed and hydrodynamical simulations performed in a specific cosmological model (e.g., a flat $\Lambda$CDM cosmology) have been used to calibrate it. In this work, we obtain for the first time self-consistent observational constraints on the gas depletion factor combining 40 X-ray emitting gas mass fraction measurements and luminosity distance measurements from type Ia supernovae. Using Gaussian Processes to reconstruct a possible redshift evolution of $\gamma$, we find no evidence for such evolution, which confirms the current results from hydrodynamical simulations. Moreover, our constraints on $\gamma$ can be seen as a data prior for cosmological analyses on different cosmological models. The current measurements are systematic limited, so future improvements will depend heavily on a better mass calibration of galaxy clusters and their measured density profiles., Comment: 7 pages, 2 figure, 1 table, JCAP Accepted

The existing degeneracy between different dark energy and modified gravity cosmologies at the background level may be broken by analysing quantities at the perturbative level. In this work, we apply a non-parametric smoothing (NPS) method to reconstruct the expansion history of the Universe ($H(z)$) from model-independent cosmic chronometers and high-$z$ quasar data. Assuming a homogeneous and isotropic flat universe and general relativity (GR) as the gravity theory, we calculate the non-relativistic matter perturbations in the linear regime using the $H(z)$ reconstruction and realistic values of $\Omega_{m0}$ and $\sigma_8$ from Planck and WMAP-9 collaborations. We find a good agreement between the measurements of the growth rate and $f\sigma_8(z)$ from current large-scale structure observations and the estimates obtained from the reconstruction of the cosmic expansion history. Considering a recently proposed null test for GR using matter perturbations, we also apply the NPS method to reconstruct $f\sigma_8(z)$. For this case, we find a $\sim 2\sigma$ tension (good agreement) with the standard relativistic cosmology when the Planck (WMAP-9) priors are used., Comment: 9 pages, 6 figures, LaTeX

Perturbative quantities, such as the growth rate ($f$) and index ($\gamma$), are powerful tools to distinguish different dark energy models or modified gravity theories even if they produce the same cosmic expansion history. In this work, without any assumption about the dynamics of the Universe, we apply a non-parametric method to current measurements of the expansion rate $H(z)$ from cosmic chronometers and high-$z$ quasar data and reconstruct the growth factor and rate of linearised density perturbations in the non-relativistic matter component. Assuming realistic values for the matter density parameter $\Omega_{m0}$, as provided by current CMB experiments, we also reconstruct the evolution of the growth index $\gamma$ with redshift. We show that the reconstruction of current $H(z)$ data constrains the growth index to $\gamma=0.56 \pm 0.12$ (2$\sigma$) at $z = 0.09$, which is in full agreement with the prediction of the $\Lambda$CDM model and some of its extensions., Comment: 7 pages, 5 figures, LaTeX

We apply two methods, namely the Gaussian processes and the non-parametric smoothing procedure, to reconstruct the Hubble parameter $H(z)$ as a function of redshift from 15 measurements of the expansion rate obtained from age estimates of passively evolving galaxies. These reconstructions enable us to derive the luminosity distance to a certain redshift $z$, calibrate the light-curve fitting parameters accounting for the (unknown) intrinsic magnitude of type Ia supernova (SNe Ia) and construct cosmological model-independent Hubble diagrams of SNe Ia. In order to test the compatibility between the reconstructed functions of $H(z)$, we perform a statistical analysis considering the latest SNe Ia sample, the so-called JLA compilation. We find that, for the Gaussian processes, the reconstructed functions of Hubble parameter versus redshift, and thus the following analysis on SNe Ia calibrations and cosmological implications, are sensitive to prior mean functions. However, for the non-parametric smoothing method, the reconstructed functions are not dependent on initial guess models, and consistently require high values of $H_0$, which are in excellent agreement with recent measurements of this quantity from Cepheids and other local distance indicators., Comment: 10 pages, 3 figures, Latex (Accepted for publication in Physical Review D)

Measurements of the cluster abundance as a function of mass and redshift provide an important cosmological test that probe not only the expansion rate but also the growth of perturbations. In this paper we adopt a scalar field scenario which admits both thawing and freezing solutions from an appropriate choice of the model parameters and derived all relevant expressions to calculate the mass function and the cluster number density. We discuss the ability of cluster observations to distinguish between these scalar field behaviors and the standard $\Lambda$CDM scenario by considering the eROSITA and SPT cluster surveys., Comment: 9 pages, 5 figures, LaTeX

The huge size and uniformity of the Sloan Digital Sky Survey makes possible an exacting test of current models of galaxy formation. We compare the predictions of the GALFORM semi-analytical galaxy formation model for the luminosities, morphologies, colours and scale-lengths of local galaxies. GALFORM models the luminosity and size of the disk and bulge components of a galaxy, and so we can compute quantities which can be compared directly with SDSS observations, such as the Petrosian magnitude and the Sersic index. We test the predictions of two published models set in the cold dark matter cosmology: the Baugh et al. (2005) model, which assumes a top-heavy initial mass function (IMF) in starbursts and superwind feedback, and the Bower et al. (2006) model, which uses AGN feedback and a standard IMF. The Bower et al model better reproduces the overall shape of the luminosity function, the morphology-luminosity relation and the colour bimodality observed in the SDSS data, but gives a poor match to the size-luminosity relation. The \Baugh et al. model successfully predicts the size-luminosity relation for late-type galaxies. Both models fail to reproduce the sizes of bright early-type galaxies. These problems highlight the need to understand better both the role of feedback processes in determining galaxy sizes, in particular the treatment of the angular momentum of gas reheated by supernovae, and the sizes of the stellar spheroids formed by galaxy mergers and disk instabilities., Comment: Accepted for publication in MNRAS. 23 pages, 24 figures. Small changes following referee's report, including more extended discussion of physical parameters affecting disk size vs luminosity relation (new Sec.4.5.4 and new Fig.20)

We report the measurements of $\Sigma (1385)$ and $\Lambda (1520)$ production in $p+p$ and $Au+Au$ collisions at $\sqrt{s_{NN}} = 200$ GeV from the STAR collaboration. The yields and the $p_{T}$ spectra are presented and discussed in terms of chemical and thermal freeze-out conditions and compared to model predictions. Thermal and microscopic models do not adequately describe the yields of all the resonances produced in central $Au+Au$ collisions. Our results indicate that there may be a time-span between chemical and thermal freeze-out during which elastic hadronic interactions occur., Comment: 6 pages, 3 figures, Phys. Rev. Lett. 97, 132301 (2006)

This paper explores educational productivity in Texas as it relates to the development of an educational productivity model based on information in the Accountability System of the Texas Education Agency. A number of educational inputs were identified that were found to be related to specific educational outputs. Stepwise regression analysis was used to develop an educational model relating independent variables to dependent variables. Initial results suggested that a richer dataset might be needed to develop a robust model. Data from the Texas Academic Excellence Indicator System (AEIS), which included achievement test scores, were then used to develop revised models. Results of these analyses produced models that were slightly improved over the preliminary models, although it was still difficult to explain much of the variance in student performance outputs from available AEIS educational inputs. In fact, the best educational productivity models that could be derived were those based on graduates and graduates with advanced seals. Appendix 1 contains a bibliography of 20 resources used to prepare this report. Appendix 2 lists the AEIS variables considered. (Contains five tables and nine references.) (SLD)

This paper focuses on the mechanics of assessing the impact of educational technology. The basics of program evaluation, research design, data collection and analysis, and report generation are covered to provide useful information to those responsible for program evaluation research and to decision makers, who are the usual recipients of evaluation reports. The proposed research models focus on the classroom as the location for data collection and analysis for both formative and summative evaluation. It is assumed that the educational technology is static to the classroom, while student movement across the campus is dynamic. Three exhibits contain templates that can be modified for use in research and evaluation studies. Exhibit 1 is the program evaluation template of suggested data elements for use in formative evaluation. Elements for data collection and analysis in summative evaluation make up Exhibit 2, and Exhibit 3 presents a list of suggested discussion items for producing a research/program evaluation report on educational technology. Contains 17 references on research methods, and 13 on statistical analysis. (SLD)

The Atlas San Juan Mission was conducted in February 2004 with the main objectives of observing the Urban Heat Island of San Juan, providing high resolution data of the land use for El Yunque Rain Forest and for calibrating remote sensors. The mission was coordinated with NASA staff members at Marshall, Stennis, Goddard, and Glenn. The Airborne Thermal and Land Applications Sensor (ATLAS) from NASA/Stennis, that operates in the visual and IR bands, was used as the main sensor and was flown over Puerto Rico in a Lear 23 jet plane. To support the data gathering effort by the ATLAS sensor, remote sensing observations and upper air soundings were conducted along with the deployment of a number of ground based weather stations and temperature sensors. This presentation focuses in the analysis of this complementary data for the Atlas San Juan Mission. Upper air data show that during the days of the mission the Caribbean mid and high atmospheres were relatively dry and highly stable reflecting positive surface lifted index, a necessary condition to conduct this suborbital campaign. Surface wind patterns at levels below 850mb were dominated by the easterly trades, while the jet stream at the edge of the troposphere dominated the westerly wind at levels above 500mb. The jet stream remained at high latitudes reducing the possibility of fronts. In consequence, only 8.4 mm of precipitation were reported during the entire mission. Observation of soundings located about 150 km apart reflected minimum variations of the boundary layer across the island for levels below 850 meters and a uniform atmosphere for higher levels. The weather stations and the temperature sensors were placed at strategic locations to observe variations across the urban and rural landscapes. Time series plot of the stations' data show that heavily urbanized commercial areas have higher air temperatures than urban and suburban residential areas, and much higher temperatures than rural areas. Temperature differences [dT(U-R)] were obtained by subtracting the values of several stations from a reference urban station, located in the commercial area of San Juan. These time series show that the UHI peaks during the morning between 10:00am and noon to an average of 4.5 C, a temporal pattern not previously observed in similar studies for continental cities. It is also observed a high variability of the UHI with the precipitation patterns even for short events. These results may be a reflection of a large land use density by low level buildings with an apparent absence of significant heat storage effects in the urban areas, and the importance of the surrounding soil and vegetation moisture in controlling the urban tropical climate. The ATLAS data was used to determine albedo and surface temperature patterns on a 10m scale for the study area. These data were used to calibrate the spatial distribution of the surface temperature when using remote sensing images from MODIS (Moderate Resolution Imaging Spectroradiometer). Surface temperatures were estimated using the land surface temperature product MOD11_L2 distributed by the Land Process Distributed Active Archive Center (LP DAAC). These results show the maximum, minimum and average temperatures in San Juan and in the entire Island at a resolution of 1 km. The information retrieved from MODIS for land surface temperatures reflected similar temporal and spatial variations as the weather stations and ATLAS measurements with a highest absolute offset of about 5 C due to the differences between surface and air temperatures.

Almost 400 college seniors (202 Anglos, 158 Chicanos, 39 Blacks) attending a large Southwestern public university completed a survey instrument to elicit what educational goals they perceived as important, whether the university had helped them realize those goals, and whether there were ethnic differences in perceived importance and realization of goals. Goals in the following categories were investigated: academics/career, student involvement at the university, and personal growth and development. Results show that the most important educational goals for all groups were those dealing with academic and career issues, thus supporting the idea of a general trend toward materialistic goals, and that all groups felt that the university had helped them realize these goals. All groups were also interested in student involvement and personal growth goals (though to lesser degrees) but, by and large, Blacks felt that the university had not helped them realize their goals in these two categories. (CMG)