Search

Possibility of using the polarized nucleus target for testing the non-standard properties of fermionic dark matter is considered. It is assumed that the incoming dark matter scatters on the polarized nuclei in the presence of vector, axial, scalar and tensor interactions. The scalar and tensor couplings are assumed to be complex numbers. Various types of measurement settings are tested depending on the assumptions regarding dark matter polarization and measurement of the recoil nucleus spin. In particular we address the question of finding and distinguishing effects of theoretically possible scenarios in which mixed triple products among various polarization vectors, the momenta of incoming dark matter and of recoil nucleus appear in the cross section. Their presence would indicate the possibility of time reversal symmetry violation in the polarized dark matter-nucleus scattering. Our considerations are model-independent and carried out in the non-relativistic dark matter and recoiled nucleus limit., Comment: 17 pages, 10 figures

We consider a cosmological model of non-minimal derivative coupling (NMDC) to gravity with holographic effect from Bekenstein-Hawking entropy using Hubble horizon IR cutoff. Holographic parameter $c$ is constant in a range, $0 \leq c < 1$. NMDC effect allows gravitational constant to be time-varying. Definition of holographic density include time-varying part of the gravitational constant. NMDC part reduces strength of gravitational constant for $\k > 0$ and opposite for $\k < 0$. The holographic part enhances gravitational strength. We use spectral index and tensor-to-scalar ratio to test the model against CMB constraint. Number of e-folding is chosen to be $N \geq 60$. Potentials, $V = V_0 \phi^n $ with $n = 2, 4$, and $V = V_0 \exp{(-\beta \phi)}$ are considered. Combined parametric plots of $\k$ and $\phi$ show that the allowed regions of the power spectrum index and of the tensor-to-scalar ratio are not overlapping. NMDC inflation is ruled out and the holographic NMDC inflation is also ruled out for $0 < c < 1$. NMDC significantly changes major anatomy of the dynamics, i.e. it gives new late-time attractor trajectories in acceleration regions. The holographic part clearly affects pattern of trajectories. However, for the holographic part to affect shape of the acceleration region, the NMDC field must be in presence. To constrain the model at late time, variation of gravitational constant is considered. Gravitational-wave standard sirens and supernovae data give a constraint, $\dot{G}/G|_{t_0} \lesssim 3\times10^{-12} \, \text{year}^{-1}$ \cite{Zhao:2018gwk} which, for this model, results in $ 10^{-12} \, \text{year}^{-1} \, \gtrsim \, {- \kappa} \dot{\phi}\ddot{\phi}/{M^2_{\p}}\,. $ Positive $\k$ is favored and greater $c^2$ results in lifting up lower bound of $\k$., Comment: 15 pages, 2 figures, 1 table, accepted by Physics of the Dark Universe

Cosmic voids are known as underdense substructures of the cosmic web that cover a large volume of the Universe. It is known that cosmic voids contain a small number of dark matter halos, so the existence of primordial black holes (PBHs) in these secluded regions of the Universe is not unlikely. In this work, we calculate the merger rate of PBHs in dark matter halos structured in cosmic voids and determine their contribution to gravitational wave events resulting from black hole mergers recorded by the Advanced Laser Interferometer Gravitational-Wave Observatory (aLIGO)-Advanced Virgo (aVirgo) detectors. Relying on the PBH scenario, the results of our analysis indicate that about $2 \sim 3$ annual events of binary black hole mergers out of all those recorded by the aLIGO-aVirgo detectors should belong to cosmic voids. We also calculate the redshift evolution of the merger rate of PBHs in cosmic voids. The results show that the evolution of the merger rate of PBHs has minimum sensitivity to the redshift changes, which seems reasonable while considering the evolution of cosmic voids. Finally, we specify the behavior of the merger rate of PBHs as a function of their mass and fraction in cosmic voids and we estimate $\mathcal{R} (M_{PBH}, f_{PBH})$ relation, which is well compatible with our findings., 11 pages; 4 figures; References are included. Physics of the Dark Universe (2023)

Direct detection experiments for light (sub-GeV) dark matter are making enormous leaps in reaching previously unexplored theory space. The need for accurate characterizations of target responses has led to a growing interplay between particle and condensed matter physics. This white paper summarizes recent progress on direct detection calculations that utilize state-of-the-art numerical tools in condensed matter physics and effective field theory techniques. These new results provide the theoretical framework for interpreting ongoing and planned experiments using electronic and collective excitations, and for optimizing future searches., Comment: contribution to Snowmass 2021; 11 pages, 3 figures

The present work deals with a dark energy model that has an oscillating scalar field potential along with a cosmological constant (CC). The oscillating part of the potential represents the contribution of a light axion field in the dark energy that has its origin in the String-Axiverse scenario. The model has been confronted with the latest cosmological observations. The results show that a sub-Planckian value of the axion field decay constant is consistent with observational data. Furthermore, in terms of the observational data considered in this work, the axion model is preferred over the $\Lambda$CDM model in terms of AIC, BIC information criteria as well as in terms of Bayesian evidence. The oscillating feature in the scalar field evolution and in the equation of state for the dark energy can be observed for the allowed parameters space. It is also observed that cluster number counts in this axion model are suppressed compared to the $\Lambda$CDM and this suppression is enhanced for the sub-Planckian values for the axion decay constant., Comment: 16 pages, LateX style. Revised Version with new data analysis. Some previous results have been strengthened

We search for a linearity in the ratio of dark matter to baryonic matter as a function of radius for galaxy clusters, motivated by a recent result by Lovas (arXiv:2206.11431), who has discovered such a linearity for a diverse suite of galaxies in the SPARC sample. For our analysis, we used a sample of 54 non-cool core clusters from the HIFLUGCS sample. We do not find any evidence for a linear trend in the aforementioned ratio as a function of radius for individual clusters. We then repeat this analysis for the stacked sample, which also does not show this linearity. Therefore, the linear scaling found by Lovas is not a universal property of dark matter haloes at all scales., 7 pages, 3 figures. Accepted for publication in Phys. Dark Universe

In this work, we analyse the late-time evolution of the universe for a particular $f(R)$ gravity model built from an exponential function of the scalar curvature. Following the literature, we write the field equations in terms of a suited statefinder function ($y_H(z)$) and considering well motivated physical initial conditions, the resulting equations are solved numerically. Also, the cosmological parameters $w_{\rm{DE}}$, $w_{\rm{eff}}$, $\Omega_{\rm{DE}}$ and $H(z)$ and the statefinder quantities $q$, $j$, $s$ and $Om(z)$ are explicitly expressed in terms of $y_H(z)$ and its derivatives. Furthermore, setting an appropriate set of values for the model parameters, the cosmological parameters as well as the statefinder quantities are plotted, and their present values (at $z=0$), are shown to be compatible with Planck 2018 observations and the $\Lambda$CDM-model values. Considering updated measurements from the dynamics of the expansion of the universe, $H(z)$, we perform an statistical analysis to constrain the free parameters of the model, finding a particular set of values that fit the data well and predict acceptable values for the cosmological and statefinder parameters at present time. Therefore, the $f(R)$ gravity model is found to be consistent with the considered observational data, and a viable alternative to explain the late-time acceleration of the universe., Comment: 23 pages, 16 figures. References added. Minor modifications, conclusions unchanged. Accepted for publication in Physics of the Dark Universe. Matched accepted version

We look at dark energy from a biology inspired viewpoint by means of the Approximate Bayesian Computation (ABC) and late time cosmological observations. We find that dynamical dark energy comes out on top, or in the ABC language naturally selected, over the standard $\Lambda$CDM cosmological scenario. We confirm this conclusion is robust to whether baryon acoustic oscillations and Hubble constant priors are considered. Our results show that the algorithm prefers low values of the Hubble constant, consistent or at least a few standard deviation away from the cosmic microwave background estimate, regardless of the priors taken initially in each model. This supports the result of the traditional MCMC analysis and could be viewed as strengthening evidence for dynamical dark energy being a more favorable model of late time cosmology., Comment: 24 pages, 14 figures, 4 tables, v2: ABC algo details and references added, accepted in Phys. Dark Universe, our codes https://github.com/reggiebernardo/notebooks/tree/main/supp_ntbks_arxiv.2211.05482

I present a model of inflation and dark energy in which the inflaton potential is constructed by imposing that a scalar field representing the classical energy of the spacetime foam inside the Hubble horizon is an exact solution to the cosmological equations. The resulting potential has the right properties to describe both the early and late expansion epochs of the universe in a unified picture., Comment: 6 pages, 4 figures. Published version

By arranging the control parameters, we examine whether the mass varying neutrino model PRD 103, 063540 (2021), enabling one to unify inflation with the present dark energy, can be used for producing an early dark energy. The model works in the following way. At early stages of the Big-Bang, the inflaton trapped in the minimum at $\phi = 0$ gets uplifted due to interaction with neutrinos and starts to roll down to one of the degenerate minima of the effective potential and after a while gets anchored at this minimum, which in turn evolves in time very slowly. Correspondingly, the early dark energy taking place as a result of this dynamical symmetry breaking also varies in time very slowly. Shortly before the recombination epoch, however, the symmetry is restored and early dark energy disappears. A typical problem of the mass varying neutrino models is that they can hardly provide the needed amount of early dark energy at the tree-level because of smallness of neutrino masses. Nevertheless, the quantum fluctuations of $\phi$ can do the job in providing sufficient early dark energy under assumption that inflationary energy scale is of the order of $1$\,TeV. Radiative as well as thermal corrections coming from the neutrino sector do not affect the model significantly. As for the gravity induced corrections to the effective potential - they can be safely ignored., Comment: 8 pages

In this work we present updated forecasts on parameterised modifications of gravity that can capture deviations of the behaviour of cosmological density perturbations beyond $\Lambda$CDM. For these forecasts we adopt the SKA Observatory (SKAO) as a benchmark for future cosmological surveys at radio frequencies, combining a continuum survey for weak lensing and angular galaxy clustering with an HI galaxy survey for spectroscopic galaxy clustering that can detect baryon acoustic oscillations and redshift space distortions. Moreover, we also add 21cm HI intensity mapping, which provides invaluable information at higher redshifts, and can complement tomographic resolution, thus allowing us to probe redshift-dependent deviations of modified gravity models. For some of these cases, we combine the probes with other optical surveys, such as the Dark Energy Spectroscopic Instrument (DESI) and the Vera C. Rubin Observatory (VRO). We show that such synergies are powerful tools to remove systematic effects and degeneracies in the non-linear and small-scale modelling of the observables. Overall, we find that the combination of all SKAO radio probes will have the ability to constrain the present value of the functions parameterising deviations from $\Lambda$CDM ($\mu$ and $\Sigma$) with a precision of $2.7\%$ and $1.8\%$ respectively, competitive with the constraints expected from optical surveys and with constraints we have on gravitational interactions in the standard model. Exploring the radio-optical synergies, we find that the combination of VRO with SKAO can yield extremely tight constraints on $\mu$ and $\Sigma$ ($0.9\%$ and $0.7\%$ respectively), which are further improved when the cross-correlation between intensity mapping and DESI galaxies is included., Comment: 24 pages, 10 figures

The Local Group (LG) of galaxies, modeled as a two body problem, is sensitive to cosmological contributions like those related to the presence of a cosmological constant $\Lambda$ into dynamics. Here we study the LG dynamics in the context of Extended Theories of Gravity like $f(R)$ gravity considered as dark energy and dark matter contributions. In the first approach, we perturb the dark energy effect considering a Yukawa-like interaction that naturally emerges from $f(R)$ gravity in the weak field limit. We assume the mass of LG from simulations and, from this, derive constraints on the Yukawa couplings: $\alpha < 0.581$ and $m_{grav} < 5.095 \cdot 10^{-26} \, eV/c^2$. In the second part, considering a minimal extension of General Relativity, i.e. $f(R) \sim R^{1+\epsilon}$, with $|\epsilon|\ll 1$, we investigate the possibility that it replaces dark matter as a MOND-like theory. We find that there is a value of the parameter $\beta$ (derived starting from $\epsilon$) which gives a minimal value for the LG mass. Moreover, this particular potential allows to calculate the ratio of dark matter and baryonic matter for the LG to be. We show that this ratio could falsify MOND-like theories., Comment: Accepted in Phys Of The Dark Univ

We examine astronomical observations that would be achievable over a future timeline corresponding to the documented history of human civilization so far, $\sim 10^4$ years. We examine implications for measurements of the redshift drift, evolution of the CMB, and cosmic parallax. A number of events that are rare on the scale of centuries will become easily observable on a timescale $\sim 10^4$ years. Implications for several measurements related to gravity are discussed., Comment: 4 pages, no figures, references updated and typos corrected

The increasingly large amount of cosmological data coming from ground-based and space-borne telescopes requires highly efficient and fast enough data analysis techniques to maximise the scientific exploitation. In this work, we explore the capabilities of supervised machine learning algorithms to learn the properties of the large-scale structure of the Universe, aiming at constraining the matter density parameter, Omega m. We implement a new Artificial Neural Network for a regression data analysis, and train it on a large set of galaxy two-point correlation functions in standard cosmologies with different values of Omega m. The training set is constructed from log-normal mock catalogues which reproduce the clustering of the Baryon Oscillation Spectroscopic Survey (BOSS) galaxies. The presented statistical method requires no specific analytical model to construct the likelihood function, and runs with negligible computational cost, after training. We test this new Artificial Neural Network on real BOSS data, finding Omega m=0.309p/m0.008, which is remarkably consistent with standard analysis results., Comment: 7 pages, 4 figures, submitted to A&A, Code available at this https URL: https://colab.research.google.com/drive/1zVxY9G5N9SNbsdjNHztVNpEhcTa6DBfu?usp=sharing

We investigate the co-evolution of dark matter (DM) density perturbation and metric perturbation in the WIMP paradigm. Instead of adopting the conventional assumption that DM starts out in thermal equilibrium, we propose a simple phase of DM production for the WIMP paradigm and extend our analysis to this phase. Being free from the envelop of thermal equilibrium, an amplified perturbative resonance between DM density perturbation and scalar modes of metric perturbation takes place during the DM production phase, and consequently results in a suppression of the tensor-to-scalar ratio of metric perturbation. By specifying the cosmic background with a typical realization of cosmic reheating, we establish a relation between DM particle mass $m_\chi$ and the tensor-to-scalar ratio $r$ in the WIMP paradigm, which also contains two reheating parameters, the reheating temperature $T_{R_f}$ and the dissipative constant $\Gamma_0$. Notably, for a sizeable parameter region of WIMP candidate and cosmic reheating, this relation predicts a smaller value of $r$ in comparing with the conventional expectation obtained by assuming DM starts out in thermal equilibrium. Once the suppression of $r$ is measured in future observations of primordial gravitational wave in CMB, this relation can be used to constrain $m_\chi$, $T_{R_f}$ and $\Gamma_0$ in principle., Comment: 21 pages, 7 figures

Gravitational waves (GWs) originated from mergers of stellar-mass binary black holes (SBBHs) are considered as dark sirens in cosmology since they usually do not have electromagnetic counterparts. In order to study cosmos with these events, we not only need the luminosity distances extracted from GW signals, but also require the redshift information of sources via, say, matching GW sky localization with galaxy catalogs. Based on such a methodology, we explore how well decihertz GW detectors, DO-Optimal and DECIGO, can constrain cosmological parameters. Using Monte-Carlo simulated dark sirens, we find that DO-Optimal can constrain the Hubble parameter to ${\sigma_{H_0}} / {H_0}\, \lesssim 0.23\%$ when estimating $H_0$ alone, while DECIGO performs better by a factor of 5 with ${\sigma_{H_0}} / {H_0}\lesssim 0.043\%$. Such a good precision of $H_0$ will shed light on the $H_0$ tension. For multiple-parameter estimation, DECIGO can still reach a level of relative uncertainty smaller than $7\%$. The reason why decihertz detectors perform well is explained by their large numbers of SBBH GW events with good distance and angular resolution., Comment: 14 pages, 8 figures, update to match published version

Recently, a covariant formulation of non-equilibrium phenomena in the context of General Relativity was proposed in order to explain from first principles the observed accelerated expansion of the Universe, without the need for a cosmological constant, leading to the GREA theory. Here, we confront the GREA theory against the latest cosmological data, including type Ia supernovae, baryon acoustic oscillations, the cosmic microwave background (CMB) radiation, Hubble rate data from the cosmic chronometers and the recent $H_0$ measurements. We perform Markov Chain Monte Carlo analyses and a Bayesian model comparison, by estimating the evidence via thermodynamic integration, and find that when all the aforementioned data are included, but no prior on $H_0$, the difference in the log-evidence is $\sim -9$ in favor of GREA, thus resulting in overwhelming support for the latter over the cosmological constant and cold dark matter model ($\Lambda$CDM). When we also include priors on $H_0$, either from Cepheids or the Tip of the Red Giant Branch measurements, then due to the tensions with CMB data the GREA theory is found to be statistically equivalent with $\Lambda$CDM., Comment: 11 pages, 4 figures, 6 tables. Changes match published version

In this paper, we investigated the theoretical and cosmological effects of the matter Lagrangian degeneracy in an extension of the Symmetric Teleparallel Equivalent of General Relativity, denoted as $f (Q, T )$ gravity. This degeneracy comes from the fact that both $\mathcal{L}_m = p$ and $\mathcal{L}_m = -\rho$ can give rise to the stress-energy tensor of a perfect fluid. The $f(Q,T)$ equations depend on the form of the matter Lagrangian and hence they also have a degeneracy that has influence on the density evolution of dust matter and radiation, on the form of the generalized Friedmann equations and also shows changes in the cosmological parameters confidence regions when performing Monte Carlo Markov Chains analyses. Our results suggest that since changing the matter Lagrangian causes different theoretical and cosmological results, future studies in $f(Q,T)$ gravity should consider both forms of the matter Lagrangians to account for the different mathematical and observational results., Comment: Accepted for publication in Physics of the Dark Universe

The consideration of the holographic dark energy approach and matter creation effects in a single cosmological model is carried out in this work accordingly, we discuss some cases of interest. We test this cosmological proposal against recent observations. Considering the best fit values obtained for the free cosmological parameters, the model exhibits a transition from a decelerated cosmic expansion to an accelerated one. The deceleration-acceleration transition can not be determined consistently from the coincidence parameter for this kind of model. At effective level the parameter state associated to the whole energy density contribution describes a quintessence scenario in the fluid analogy at present time., 9 pages, 7 figures. Accepted for publication in Physics of the Dark Universe

We investigate a cosmological scenario in which the dark matter particles can be created during the evolution of the Universe. By regarding the Universe as an open thermodynamic system and using non-equilibrium thermodynamics, we examine the mechanism of gravitational particle production. In this setup, we study the large-scale structure (LSS) formation of the Universe in the Newtonian regime of perturbations and derive the equations governing the evolution of the dark matter overdensities. Then, we implement the cosmological data from Planck 2018 CMB measurements, SNe Ia and BAO observations, as well as the Riess et al. (2019) local measurement for $H_0$ to provide some cosmological constraints for the parameters of our model. We see that the best case of our scenario ($\chi_{{\rm tot}}^{2}=3834.40$) fits the observational data better than the baseline $\Lambda$CDM model ($\chi_{{\rm tot}}^{2} = 3838.00$) at the background level. We moreover estimate the growth factor of linear perturbations and show that the best case of our model ($\chi_{f\sigma_{8}}^{2}=39.85$) fits the LSS data significantly better than the $\Lambda$CDM model ($\chi_{f\sigma_{8}}^{2}=45.29$). Consequently, our model also makes a better performance at the level of the linear perturbations compared to the standard cosmological model., Comment: 30 pages, 8 figures

The logotropic model [P.H. Chavanis, Eur. Phys. J. Plus {\bf 130}, 130 (2015)] may be an interesting alternative to the $\Lambda$CDM model. It is able to account for the present accelerating expansion of the universe while solving at the same time the core-cusp problem of the CDM model. In the logotropic model, there is a single dark fluid. Its rest-mass plays the role of dark matter and its internal energy plays the role of dark energy. We highlight two remarkable predictions of the logotropic model. It yields cored dark matter halos with a universal surface density equal to $\Sigma_0^{\rm th}=0.01955 c\sqrt{\Lambda}/G=133\, M_{\odot}/{\rm pc}^2$ without free parameter in very good agreement with the observational value $\Sigma_0^{\rm obs}=141_{-52}^{+83}\, M_{\odot}/{\rm pc}^2$. It also predicts the present ratio of dark energy and dark matter to be the pure number $\Omega_{\rm de,0}^{\rm th}/\Omega_{\rm dm,0}^{\rm th}=e=2.71828...$ in very good agreement with the observations giving $\Omega_{\rm de,0}^{\rm obs}/\Omega_{\rm dm,0}^{\rm obs}=2.669\pm 0.08$. Using the measured present proportion of baryonic matter $\Omega_{\rm b,0}^{\rm obs}=0.0486\pm 0.0010$, we find that the values of the present proportion of dark matter and dark energy are $\Omega_{\rm dm,0}^{\rm th}=\frac{1}{1+e}(1-\Omega_{\rm b,0})=0.2559$ and $\Omega_{\rm de,0}^{\rm th}=\frac{e}{1+e}(1-\Omega_{\rm b,0})=0.6955$ in very good agreement with the observational values $\Omega_{\rm dm,0}^{\rm obs}=0.2589\pm 0.0057$ and $\Omega_{\rm de,0}^{\rm obs}=0.6911\pm 0.0062$ within the error bars. These theoretical predictions are obtained by advocating a mysterious strong cosmic coincidence (dubbed "dark magic") implying that our epoch plays a particular role in the history of the universe., Comment: arXiv admin note: text overlap with arXiv:2109.05963

Stochastic gravitational waves can be induced from the primordial curvature perturbations generated during inflation, through scalar-tensor mode coupling at the second order of cosmological perturbation theory. Here we discuss a model of warm inflation in which large curvature perturbations are generated at the small scales because of inflaton dissipation. These overdense perturbations then collapse at later epoch to form primordial black holes, as was studied in our earlier work (Ref. \cite{Arya:2019wck}), and therefore may also act as a source to the second-order tensor perturbations. In this study, we calculate the spectrum of these secondary gravitational waves from our warm inflationary model. We find that our model leads to a generation of scalar induced gravitational waves (SIGW) over a frequency range ($1-10^6$) Hz. Further, we discuss the detection possibilities of these SIGWs, taking in account the sensitivity of different ongoing and future gravitational wave experiments., Comment: 16 pages, 4 figures. Comments and suggestions are welcome

We combine cosmic chronometer and growth of structure data to derive the redshift evolution of the dark energy equation of state $w$, using a novel agnostic approach. The background and perturbation equations lead to two expressions for $w$, one purely background-based and the other relying also on the growth rate of large-scale structure. We compare the features and performance of the growth-based $w$ to the background $w$, using Gaussian Processes for the reconstructions. We find that current data is not precise enough for robust reconstruction of the two forms of $w$. By using mock data expected from next-generation surveys, we show that the reconstructions will be robust enough and that the growth-based $w$ will out-perform the background $w$. Furthermore, any disagreement between the two forms of $w$ will provide a new test for deviations from the standard model of cosmology., Comment: 10 pages, 6 figures. Version accepted in Physics of the Dark Universe

In this work, we reanalyze the multi-component strongly interacting massive particle (mSIMP) scenario using an effective operator approach. As in the single-component SIMP case, the total relic abundance of mSIMP dark matter (DM) is determined by the coupling strengths of $3 \to 2$ processes achieved by a five-point effective operator. Intriguingly, we notice that there is an irreducible $2 \to 2$ process induced by the corresponding five-point interaction in the dark sector, which would reshuffle the mass densities of SIMP DM after the chemical freeze-out. We dub this DM scenario as reshuffled SIMP ($r$SIMP). Given this observation, we then numerically solve the coupled Boltzmann equations including the $3 \to 2$ and $2 \to 2$ processes to get the correct yields of $r$SIMP DM. It turns out that the masses of $r$SIMP DM must be nearly degenerate for them to contribute sizable abundances. On the other hand, we also introduce effective operators to bridge the dark sector and visible sector via a vector portal coupling. Notably, we find that the reshuffled mechanism in the $r$SIMP scenario is sensitive to the size of the DM self-interacting cross section., Comment: 8 pages, 3 figures, 3 tables, the title changed. Matches the version published in Phys.Dark Univ

Assuming for Weakly Interacting Massive Particles (WIMPs) a Maxwellian velocity distribution in the Galaxy we provide an assessment of the sensitivity of existing Dark Matter (DM) direct detection (DD) experiments to operators up to dimension 7 of the relativistic effective field theory describing dark matter interactions with quarks and gluons . In particular we focus on a systematic approach, including an extensive set of experiments and large number of couplings, both exceeding for completeness similar analyses in the literature. The relativistic effective theory requires to fix one coupling for each quark flavor, so in principle for each different combination the bounds should be recalculated starting from direct detection experimental data. To address this problem we propose an approximate model-independent procedure that allows to directly calculate the bounds for any combination of couplings in terms of model-independent limits on the Wilson coefficients of the non-relativistic theory expressed in terms of the WIMP mass and of the neutron-to-proton coupling ratio $c^n/c^p$. We test the result of the approximate procedure against that of a full calculation, and discuss its possible pitfalls and limitations. We also provide a simple interpolating interface in Python that allows to apply our method quantitatively., Comment: 23 pages, 11 figures, 2 tables. Updated to published version. The companion code can be downloaded from https://github.com/NRDD-constraints/NRDD

A search for Weakly Interacting Massive Particles (WIMPs) was conducted with the single-phase liquid-xenon detector XMASS through inelastic scattering in which $^{129}$Xe nuclei were excited, using an exposure ($\rm 327\; kg \times 800.0 \; days$) 48 times larger than that of our previous study. The inelastic excitation sensitivity was improved by detailed evaluation of background, event classification based on scintillation timing that distinguished $\gamma$-rays and $\beta$-rays, and simultaneous fitting of the energy spectra of $\gamma$-like and $\beta$-like samples. No evidence of a WIMP signal was found. Thus, we set the upper limits of the inelastic channel cross section at 90\% confidence level, for example, $4.1\times 10^{-39} \;{\rm cm^2}$ for a $200\; {\rm GeV}/c^2$ WIMP. This result provides the most stringent limits on the SD WIMP-neutron interaction and is better by a factor of 7.7 at $200\;{\rm GeV}/c^2$ than the existing experimental limit., Comment: 8 pages, 10 figures

Multiple observations made by several different telescopes have shown asymmetry between the number of spiral galaxies rotating in opposite directions in different parts of the sky. One of the immediate questions regarding the possible asymmetry of the spin directions is whether the distribution forms a cosmological-scale axis. This paper analyzes and compares 10 different datasets published in the past decade, collected by SDSS, Pan-STARRS, and Hubble Space Telescope. The datasets contain spiral galaxies separated by their spin direction, and the distribution can show dipole axes. The analysis shows that the directions of the most probable dipole axes are consistent in datasets that have similar average redshift, but different between datasets that have different average redshift. The analysis also shows that the location of the most probable axis correlates with the average redshift of the galaxies in the datasets. That is, the location of the most probable axis shifts when the redshift gets higher, and the correlation is statistically significant. This provides a certain indication of a drift in a possible axis formed by the distribution of galaxy spin directions, or a cosmological scale structure that peaks at a certain distance from Earth., Comment: New Astronomy, accepted

Indirect insights of Pop III stars and Black Holes (BHs) at Cosmic Dawn (CD) may be imprinted as an absorption signal in the 21cm line of HI against the CMB, when the Universe was less than 200 Myr old. To explain the additional large amplitude of the 21cm HI absorption reported by EDGES there have been proposed models based on an additional synchrotron Cosmic Radio Background (CRB) from BH-jet sources that boost the HI absorption signal at CD. The recent observations of radio loud supermassive BHs (SMBHs) in high-z quasars up to z=7 suggest the existence of a CRB from growing BHs at z > 15, of unknown intensity. To match the onset of the EDGES signal a CRB of comparable intensity to that of the CMB is required. Here we provide approximate calculations to analyze this type of absorption signals, taking that of EDGES as an example. Assuming a BH mass to radio luminosity ratio as observed in radio-loud SMBHs of ~10^9 solar masses in quasars at z = 6-7, we find that rapidly growing radio luminous BHs of Intermediate Mass (IMBHs) in their way to become SMBHs, are the only type of astrophysical radio sources of a CRB that could explain the amplitude of the HI absorption reported by EDGES in the interval of z = 18-20. At those redshifts the EDGES signal would imply that the global mass density of IMBHs must be dominant over that of stars, more than 70% of the maximum Stellar Mass Density (SMD) expected at those high redshifts. This suggests that those IMBHs are formed before and grow faster than the bulk of stars, with no large mass contribution from stellar-mass BH remnants of typical Pop III stars. The highly redshifted signals from these IMBHs may be detected at long radio wavelengths with ultrasensitive interferometers such as the SKA, in the infrared with the JWST, and in the X-rays with future space missions., 34 pages, 2 figures, 1 table. Accepted for publication in New Astronomy Reviews

The fundamental nature and origin of dark energy are one of the premier mysteries of theoretical physics. In General Relativity Theory, the cosmological constant $\Lambda$ is the simplest explanation for dark energy. On the other hand, the cosmological constant $\Lambda$ suffers from a delicate issue so-called fine-tuning problem. This motivates one to modify the spacetime geometry of Einstein's GR. The $f(Q)$ gravity is a recently proposed modified theory of gravity in which the non-metricity scalar $Q$ drives the gravitational interaction. In this article, we consider a linear $f(Q)$ model, specifically $f(Q)=\alpha Q + \beta$, where $\alpha$ and $\beta$ are free parameters. Then we estimate the best fit values of model parameters that would be in agreement with the recent observational data sets. We use 57 points of the updated $H(z)$ data sets, 6 points of the BAO data sets, and 1048 points from the Pantheon supernovae samples. We apply the Bayesian analysis and likelihood function along with the Markov Chain Monte Carlo (MCMC) method. Further, we analyse the physical behaviour of cosmological parameters such as density, deceleration, and the EoS parameters corresponding to the constraint values of the model parameters. The evolution of deceleration parameter predicts a transition from decelerated to accelerated phases of the universe. Further, the evolution of equation of state parameter depicts quintessence type behaviour of the dark energy fluid part. We found that our $f(Q)$ cosmological model can effectively describe the late time cosmic acceleration without invoking any dark energy component in the matter part., Comment: PDU revised version

The inner part of dense clusters of primordial black holes is an active environment where multiple scattering processes take place. Some of them give rise from time to time to bounded pairs, and the rest ends up with a single scattering event. The former eventually evolves to a binary black hole (BBH) emitting periodic gravitational waves (GWs), while the latter with a short distance, called close hyperbolic encounters (CHE), emits a strong GW burst. We make the first calculation of the stochastic GW background originating from unresolved CHE sources. Unlike the case for BBH, the low-frequency tail of the SGWB from CHE is sensitive to the redshift dependence of the event rate, which could help distinguish the astrophysical from the primordial black hole contributions. We find that there is a chance that CHE can be tested by third-generation ground-based GW detectors such as Einstein Telescope and Cosmic Explorer., Comment: 7 pages, 1 figure. Changes match published version

A novel 4-dimensional Einstein-Gauss-Bonnet (4D EGB) gravity has been proposed that asserts to bypass the Lovelock's theorem and to result in a non-trivial contribution to the gravitational dynamics in four-dimensional spacetime. In this work, we study the integrated Sachs-Wolfe (ISW) effect in the 4D EGB model. For this purpose, we calculate the evolution of the gravitational potential and the linear growth factor as a function of redshift for the 4D EGB model and compare it with the corresponding result obtained from the $\Lambda$-cold dark matter ($\Lambda$CDM) model. We also calculate the ISW-auto power spectrum and the ISW-cross power spectrum as functions of cosmic microwave background (CMB) multipoles for the 4D EGB model and compare those with the one obtained from the $\Lambda$CDM model. To do this, we use the strongest constraint on the coupling parameter proposed for the 4D EGB model. Additionally, to calculate the ISW effect for the 4D EGB model, we employ three large-scale structure surveys from different wavelengths. The results exhibit that the ISW effect in the 4D EGB model is higher than the one obtained from the $\Lambda$CDM model. Hence, we show that the 4D EGB model can amplify the amplitude of the ISW power spectrum, which can be considered as a relative advantage of the 4D EGB model comparing the $\Lambda$CDM one. Also, we indicate that the deviation from the $\Lambda$CDM model is directly proportional to the value of the dimensionless coupling parameter $\beta$., Comment: 10 pages, 2 tables, fixed some typos, added some reference

In the context of a ghost free f(R,G) model, we present a non-singular cosmological scenario in which the universe initially contracts through an ekpyrotic phase having a bouncing like behaviour, and following the bounce, it smoothly transits to a matter or radiation like deceleration era which is further smoothly connected to the dark energy era at present epoch. The ghost free character of the model is ensured by the presence of a Lagrange multiplier, and we consider the Gauss–Bonnet (GB) coupling function in such a way that it gets compatible with the event GW170817. Using suitable reconstruction technique, we obtain the non-trivial scalar field potential as well as the GB coupling function. Such scalar potential and GB coupling function source a smooth unified scenario from an ekpyrotic bounce to the dark energy era with an intermediate deceleration era. The occurrence of ekpyrotic contraction phase justifies the resolution of the anisotropic problem (also known as BKL instability) in the background evolution. Consequently we determine the background Hubble parameter and the corresponding effective equation of state parameter, and discussed several qualitative features of the model. The Hubble radius shows an asymmetric behaviour around the bounce, in particular, the evolution of the Hubble radius leads to the generation era of the primordial perturbation modes far before the bounce in the deep sub-Hubble regime. Accordingly we perform the scalar and tensor perturbation evolution in the present context, and as a result, the scalar power spectrum at large scale modes is found to be problematic. Thus an extended scenario is proposed where we consider a pre-ekpyrotic phase having the equation of state parameter is less than unity, and re-examine the scalar and tensor power spectra, on large scales that cross the Hubble radius during the pre-ekpyrotic stage. In this regard, the GB coupling function shows considerable effects in reducing the tensor to scalar ratio compared to the case where the GB coupling is absent. Furthermore the dark energy epoch is consistent with the Planck+SNe+BAO data., This work was supported in part by the JSPS, Japan Grant-in-Aid for Scientific Research (C) No. 18K03615 (SN) and by MINECO (Spain), project PID2019-104397GB-I00 (SDO). This work was partially supported by the program Unidad de Excelencia MarAa de Maeztu CEX2020-001058-M. This research was also supported in part by the International Centre for Theoretical Sciences (ICTS) for the online program - Physics of the Early Universe (code: ICTS/peu2022/1).

We investigate the gravitational wave spectrum originating from the cosmological first-order phase transition. We compare two models: one is a scalar field model without gravitation, while the other is a scalar field model with gravitation. Based on the sensitivity curves of the LISA space-based interferometer on the stochastic gravitational-wave background, we compare the difference between the gravitational wave spectra of the former and the latter cases obtained from the bubble collision process. In particular, we numerically calculate the speed of the bubble wall before collision for the two models. We demonstrate that the difference between the amplitudes of these spectra can clearly distinguish between the two models. We expect that the LISA with Signal to Noise Ratio = 10 could observe the spectrum as the fast first-order phase transition.

1. We find that any two distance moduli measurements for the same galaxy differ from each other by 2.07 times the reported one sigma uncertainty on average. 2. This average difference between distance moduli measurements of the same galaxy as a multiple of reported uncertainty is growing with time of publication, rising to 3.00 times the reported one sigma uncertainty for all distances reported from 2014 to 2018. 3. This average difference between distance moduli measurements of the same galaxy as a multiple of reported one sigma uncertainty is highest for the standard candles (3.01) including Cepheids (4.26), Type Ia Supernovae (2.85), and Tip of the Red Giant Branch (2.82). 4. This data points to a possible systematic underestimation of uncertainties in extragalactic distances. 5. The results also give a possible way out of the Hubble-Lemaitre tension by advocating for increasing the error bars on Hubble-Lemaitre constant measured via distance ladders of standard candles and rulers., 11 pages, 7 figures, 2 tables, 2 appendix tables

Cosmic backreaction as an additional source of the expansion of the universe has been a debate topic since the discovery of cosmic acceleration. The major concern is whether the self interaction of small-scale nonlinear structures would source gravity on very large scales. Gregory Ryskin argued against the additional inclusion of gravitational interaction energy of astronomical objects, whose masses are mostly inferred from gravitational effects and hence should already contain all sources with long-range gravity forces. Ryskin proposed that the backreaction contribution to the energy momentum tensor is instead from the rest of the universe beyond the observable patch. Ryskin's model elegantly solves the fine-tuning problem and is in good agreement with the Hubble diagram of Type Ia supernovae. In this article we revisit Ryskin's model and show that it is {\it inconsistent} with at least one of the following statements: (i) the universe is matter-dominated at low redshift ($z\lesssim 2$); (ii) the universe is radiation-dominated at sufficiently high redshift; (iii) matter density fluctuations are tiny ($\lesssim 10^{-4}$) at the recombination epoch., 7 pages; 2 figures; submitted to Astroparticle Physics

Convolutional Neural Networks (CNNs) are a cornerstone of the Deep Learning toolbox and have led to many breakthroughs in Artificial Intelligence. These networks have mostly been developed for regular Euclidean domains such as those supporting images, audio, or video. Because of their success, CNN-based methods are becoming increasingly popular in Cosmology. Cosmological data often comes as spherical maps, which make the use of the traditional CNNs more complicated. The commonly used pixelization scheme for spherical maps is the Hierarchical Equal Area isoLatitude Pixelisation (HEALPix). We present a spherical CNN for analysis of full and partial HEALPix maps, which we call DeepSphere. The spherical CNN is constructed by representing the sphere as a graph. Graphs are versatile data structures that can act as a discrete representation of a continuous manifold. Using the graph-based representation, we define many of the standard CNN operations, such as convolution and pooling. With filters restricted to being radial, our convolutions are equivariant to rotation on the sphere, and DeepSphere can be made invariant or equivariant to rotation. This way, DeepSphere is a special case of a graph CNN, tailored to the HEALPix sampling of the sphere. This approach is computationally more efficient than using spherical harmonics to perform convolutions. We demonstrate the method on a classification problem of weak lensing mass maps from two cosmological models and compare the performance of the CNN with that of two baseline classifiers. The results show that the performance of DeepSphere is always superior or equal to both of these baselines. For high noise levels and for data covering only a smaller fraction of the sphere, DeepSphere achieves typically 10% better classification accuracy than those baselines. Finally, we show how learned filters can be visualized to introspect the neural network., arXiv admin note: text overlap with arXiv:astro-ph/0409513 by other authors

Deep convolutional neural networks (DCNNs) have become the most common solution for automatic image annotation due to their non-parametric nature, good performance, and their accessibility through libraries such as TensorFlow. Among other fields, DCNNs are also a common approach to the annotation of large astronomical image databases acquired by digital sky surveys. One of the main downsides of DCNNs is the complex non-intuitive rules that make DCNNs act as a ``black box", providing annotations in a manner that is unclear to the user. Therefore, the user is often not able to know what information is used by the DCNNs for the classification. Here we demonstrate that the training of a DCNN is sensitive to the context of the training data such as the location of the objects in the sky. We show that for basic classification of elliptical and spiral galaxies, the sky location of the galaxies used for training affects the behavior of the algorithm, and leads to a small but consistent and statistically significant bias. That bias exhibits itself in the form of cosmological-scale anisotropy in the distribution of basic galaxy morphology. Therefore, while DCNNs are powerful tools for annotating images of extended sources, the construction of training sets for galaxy morphology should take into consideration more aspects than the visual appearance of the object. In any case, catalogs created with deep neural networks that exhibit signs of cosmological anisotropy should be interpreted with the possibility of consistent bias., Comment: A&C, accepted

We study cosmological perturbations in a model of unified dark matter and dark energy with a sharp transition in the late-time universe. The dark sector is described by a dark fluid which evolves from an early stage at redshifts $z > z_C$ when it behaves as cold dark matter (CDM) to a late time dark energy (DE) phase ($z < z_C$) when the equation of state parameter is $w = -1 + \epsilon$, with a constant $\epsilon$ which must be in the range $0 < \epsilon < 2/3$. We show that fluctuations in the dark energy phase suffer from an exponential instability, the mode functions growing both as a function of comoving momentum $k$ and of conformal time $\eta$. In order that this exponential instability does not lead to distortions of the energy density power spectrum on scales for which we have good observational results, the redshift $z_C$ of transition between the two phases is constrained to be so close to zero that the model is unable to explain the supernova data., Comment: 17 pages; 2 figures; v2: minor changes to match the published version

I describe a fast algorithm for the identification of connected sets of points where the point-wise connections are determined by a fixed spatial distance - a task commonly referred to in the cosmological simulation community as Friends-of-Friends (FOF) group finding. This technique sorts particles into fine cells sufficiently compact to guarantee their cohabitants are linked, and uses locality sensitive hashing to search for neighbouring (blocks of) cells. Tests on N-body simulations of up to a billion particles exhibit speed increases of factors up to 20x compared with FOF via trees (a factor around 8 is typical), and is consistently complete in less than the time of a k-d tree construction, giving it an intrinsic advantage over tree-based methods. The code is open-source and available online at https://github.com/pec27/hfof ., Comment: Accepted in Astronomy and Computing. 11 pages, 5 figures, updated to match accepted version

The act of projecting data sampled on the surface of the celestial sphere onto a regular grid on the plane can introduce error and a loss of information. This paper evaluates the effects of different planar projections on non-Gaussian statistics of weak lensing convergence maps. In particular we investigate the effect of projection on peak counts and Minkowski Functionals (MFs) derived from convergence maps and the suitability of a number of projections at matching the peak counts and MFs obtained from a sphere. We find that the peak counts derived from planar projections consistently overestimate the counts at low SNR thresholds and underestimate at high SNR thresholds across the projections evaluated, although the difference is reduced when smoothing of the maps is increased. In the case of the Minkowski Functionals, V 0 is minimally affected by projection used, while projected V 1 and V 2 are consistently overestimated with respect to the spherical case.

To understand the formation and evolution of galaxies at redshifts z < 10, one must invariably introduce specific models (e.g., for the star formation) in order to fully interpret the data. Unfortunately, this tends to render the analysis compliant to the theory and its assumptions, so consensus is still somewhat elusive. Nonetheless, the surprisingly early appearance of massive galaxies challenges the standard model, and the halo mass function estimated from galaxy surveys at z > 4 appears to be inconsistent with the predictions of LCDM, giving rise to what has been termed "The Impossibly Early Galaxy Problem" by some workers in the field. A simple resolution to this question may not be forthcoming. The situation with the halos themselves, however, is more straightforward and, in this paper, we use linear perturbation theory to derive the halo mass function over the redshift range z < 10 for the R_h=ct universe. We use this predicted halo distribution to demonstrate that both its dependence on mass and its very weak dependence on redshift are compatible with the data. The difficulties with LCDM may eventually be overcome with refinements to the underlying theory of star formation and galaxy evolution within the halos. For now, however, we demonstrate that the unexpected early formation of structure may also simply be due to an incorrect choice of the cosmology, rather than to yet unknown astrophysical issues associated with the condensation of mass fluctuations and subsequent galaxy formation., 23 pages, 2 figures. Accepted for publication in Physics of the Dark Universe

Hubble tension and the search for preferred direction are two crucial unresolved issues in modern cosmology. Different measurements of the Hubble constant provide significantly different values, and this is known as the Hubble tension. The cosmological principle assumes that the universe is homogeneous and isotropic; however, deviations from the isotropy have often been observed. We apply the Bayesian tools and the Extreme Value theory dependent statistic to address the above issues. These techniques have been applied to the Panstarrs1 type Ia supernovae data. Our analysis for Hubble constant does not reject the Hubble tension. However, our value is smaller than that of the SHoES program and agrees with the CCHP value. Extreme value theory-based analysis indicates that the data does not show direction dependence. As a byproduct of our technique, we show that the errors in the data are non-Gaussian in nature., 10 pages, 5 figures

Dark sector, constituting about 95 percent of the Universe, remains the subject of numerous studies. There are lots of models dealing with the cause of the effects assigned to dark matter and dark energy. This brief review is devoted to the very recent theoretical advances in these areas: only to the advances achieved in the last few years. For example, in section devoted to particle dark matter we overview recent publications on sterile neutrinos, self-interacting dark matter, dibarions, dark matter from primordial bubbles, primordial black holes as dark matter, axions escaping from neutron stars, and dark and usual matter interacting via the fifth dimension. We also overview the second flavor of hydrogen atoms: their existence was proven by analyzing atomic experiments and is also evidenced by the latest astrophysical observations of the 21 cm spectral line from the early Universe. While discussing non-particle models of the cause of dark matter effects, we refer to modified Newtonian dynamics and modifications of the strong equivalence principles. We also consider exotic compact objects, primordial black holes, and retardation effects. Finally, we review recent studies on the cause of dark energy effects. Specifically, we cover two disputes that arose in 2019 and 2020 on whether the observations of supernovas, previously interpreted as the proof of the existence of dark energy, could have alternative explanations. Besides, we note a study of 2021, where dark energy is substituted by a new hypothetical type of dark matter having a magnetic-type interaction. We also refer to the recent model of a system of nonrelativistic neutral gravitating particles providing an alternative explanation of the entire dynamics of the Universe expansion. without introducing dark energy or new gravitational degrees of freedom.

We present FlowPM, a Particle-Mesh (PM) cosmological N-body code implemented in Mesh-TensorFlow for GPU-accelerated, distributed, and differentiable simulations. We implement and validate the accuracy of a novel multi-grid scheme based on multiresolution pyramids to compute large scale forces efficiently on distributed platforms. We explore the scaling of the simulation on large-scale supercomputers and compare it with corresponding python based PM code, finding on an average 10x speed-up in terms of wallclock time. We also demonstrate how this novel tool can be used for efficiently solving large scale cosmological inference problems, in particular reconstruction of cosmological fields in a forward model Bayesian framework with hybrid PM and neural network forward model. We provide skeleton code for these examples and the entire code is publicly available at https://github.com/modichirag/flowpm., Comment: 14 pages, 17 figures. Code provided at https://github.com/modichirag/flowpm

We carry out a test of the radial acceleration relation (RAR) for a sample of 10 dynamically relaxed and cool-core galaxy clusters imaged by the Chandra X-ray telescope, which was studied in Giles et al. For this sample, we observe that the best-fit RAR shows a very tight residual scatter equal to 0.09 dex. We obtain an acceleration scale of $1.59 \times 10^{-9} m/s^2$, which is about an order of magnitude higher than that obtained for galaxies. Furthermore, the best-fit RAR parameters differ from those estimated from some of the previously analyzed cluster samples, which indicates that the acceleration scale found from the RAR could be of an emergent nature, instead of a fundamental universal scale., 6 pages, 2 figures. Accepted for publication in Phys. Dark Universe

In this paper, we propose a new method to obtain the depletion factor $\gamma(z)$, the ratio by which the measured baryon fraction in galaxy clusters is depleted with respect to the universal mean. We use exclusively galaxy cluster data, namely, X-ray gas mass fraction ($f_{gas}$) and angular diameter distance measurements from Sunyaev-Zel'dovich effect plus X-ray observations. The galaxy clusters are the same in both data set and the non-isothermal spherical double $\beta$-model was used to describe their electron density and temperature profiles. In order to compare our results with those from recent cosmological hydrodynamical simulations, we suppose a possible time evolution for $\gamma(z)$, such as, $\gamma(z) = \gamma_0(1 + \gamma_1z)$. As main conclusions we found that: the $\gamma_0$ value is in full agreement with the simulations. { On the other hand, although the $\gamma_1$ value found in our analysis is compatible with $\gamma_1=0$ within 2$\sigma$ c.l., our results show a non-negligible time evolution for the depletion factor, unlike the results of the simulations. However, we also put constraints on $\gamma (z)$ by using the $f_{gas}$ measurements and angular diameter distances obtained from the flat $\Lambda$CDM model (Planck results) and from a sample of galaxy clusters described by a elliptical profile. For these cases no significant time evolution for $\gamma(z)$ was found. Then, if a constant depletion factor is an inherent characteristic of these structures, our results show that the spherical double $\beta$-model used to describe the galaxy clusters considered does not affect the quality of their $f_{gas}$ measurements., Comment: 10 pages, 4 figures, I table, Accepted for publication in the Astroparticle Physics

New Experiments With Spheres-Gas (NEWS-G) is a direct dark matter detection experiment using Spherical Proportional Counters (SPCs) with light noble gases to search for low-mass Weakly Interacting Massive Particles (WIMPs). We report the results from the first physics run taken at the Laboratoire Souterrain de Modane (LSM) with SEDINE, a 60 cm diameter prototype SPC operated with a mixture of $\mathrm{Ne}+\mathrm{CH}_{4}$ (0.7 %) at 3.1 bars for a total exposure of $9.7\;\mathrm{kg\cdot days}$. New constraints are set on the spin-independent WIMP-nucleon scattering cross-section in the sub-$\mathrm{GeV/c^2}$ mass region. We exclude cross-sections above $4.4 \times \mathrm{10^{-37}\;cm^2}$ at 90 % confidence level (C.L.) for a 0.5 $\mathrm{GeV/c^2}$ WIMP. The competitive results obtained with SEDINE are promising for the next phase of the NEWS-G experiment: a 140 cm diameter SPC to be installed at SNOLAB by summer 2018., Comment: 18 pages, 10 figures, acknowledgments section updated

The generalized Chaplygin gas cosmology provides a prime example for the class of unified dark matter models, which substitute the two dark components of the standard cosmological ΛCDM concordance model by a single dark component. The equation of state of the generalized Chaplygin gas is characterised by a parameter α such that the standard ΛCDM model is recovered in the case α = 0 with respect to the background dynamics and the cosmic microwave background (CMB) statistics. This allows to investigate the concordance of different cosmological data sets with respect to α. We compare the supernova data of the Supernova Cosmology Project, the data of the baryon oscillation spectroscopic survey (BOSS) of the third Sloan digital sky survey (SDSS-III) and the CMB data of the Planck 2015 data release. The importance of the BOSS Lyman α forest BAO measurements is investigated. It is found that these data sets possess a common overlap of the confidence domains only for Chaplygin gas cosmologies very close to the ΛCDM model.

We present a new galaxy cluster catalog constructed from SDSS DR9 using an Adaptive Matched Filter technique. Our main catalog has 46,479 galaxy clusters with richness $\Lambda_{200} > 20$ in the redshift range 0.045 $\le z 40$, while WHL matches $\geq$70$\%$ of these missed clusters on average. We also match the AMF catalog with the X-ray cluster catalogs BAX, MCXC and a combined catalog from NORAS and REFLEX. We consistently obtain a greater number of one-to-one matches for X-ray clusters across higher luminosity bins ($L_x>6 \times 10^{44}$ ergs/sec) than redMaPPer while WHL matches the most clusters overall. For the most luminous clusters ($L_x>8$), our catalog performs equivalently to WHL. This new catalog provides a wider sample than redMaPPer while retaining many fewer objects than WHL., Comment: Submitted to New Astronomy

Primordial black holes (PBH) have been shown to arise from high peaks in the matter power spectra of multi-field models of inflation. Here we show, with a simple toy model, that it is also possible to generate a peak in the curvature power spectrum of single-field inflation. We assume that the effective dynamics of the inflaton field presents a near-inflection point which slows down the field right before the end of inflation and gives rise to a prominent spike in the fluctuation power spectrum at scales much smaller than those probed by Cosmic Microwave Background (CMB) and Large Scale Structure (LSS) observations. This peak will give rise, upon reentry during the radiation era, to PBH via gravitational collapse. The mass and abundance of these PBH is such that they could constitute the totality of the Dark Matter today. We satisfy all CMB and LSS constraints and predict a very broad range of PBH masses. Some of these PBH are light enough that they will evaporate before structure formation, leaving behind a large curvature fluctuation on small scales. This broad mass distribution of PBH as Dark Matter will be tested in the future by AdvLIGO and LISA interferometers., Comment: 13 pages, 6 figures. Matches version published in PDU