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This article introduces new neutrosophic principles aiming to extend and generalize the concepts of locality and nonlocality by addressing scenarios involving indeterminacy, together with partiality and multitude, in physics, mechanics, cosmology, biology, medicine, chemistry, economics, ecology, sociology. Locality refers to interactions or processes confined within a limited region of space or time. But there may be a Total (100%) Locality, or a Partial Locality (less than 100% and greater than 0%). The effects are constrained to the immediate environment. Contrariwise, NonLocality refers to interactions or connections between entities separated by space or time. The changes in one location have instantaneous effects on another. Similarly, there may be a Total (100%) NonLocality, or a Partial NonLocality (less than 100% and greater than 0%). Total (100%) or Partial (less than 100% and greater than 0%) Indeterminacy may arise from hidden variables and from environment. For instance, it may involve nonlocal connections between objects that are only partially entangled or influence each other in limited ways, rather than exhibiting complete freedom. The Principle of Partial Locality, Partial Indeterminacy, and Partial NonLocality implies an interplay of locality, indeterminacy, and nonlocality acting in a dynamic neutrosophic system. A generalization of (Locality, Indeterminacy, NonLocality) is the (MultiLocality, MultiIndeterminacy, MultiNonLocality). Practical examples from different fields are provided. [ABSTRACT FROM AUTHOR]

We present the first set of galaxy scaling relations derived from kinematic models of the Widefield Australian Square Kilometer Array Pathfinder (ASKAP) L -band Legacy All-sky Blind surveY (WALLABY) pilot phase observations. Combining the results of the first and second pilot data releases, there are 236 available kinematic models. We develop a framework for robustly measuring H i disk structural properties from these kinematic models, applicable to the full WALLABY survey. Utilizing this framework, we obtained the H i size, a measure of the rotational velocity, and angular momentum for 148 galaxies. These comprise the largest sample of galaxy properties from an untargeted, uniformly observed, and modeled H i survey to date. We study the neutral atomic hydrogen (H i) size–mass, size–velocity, mass–velocity, and angular momentum–mass scaling relations. We calculate the slope, intercept, and scatter for these scaling relations and find that they are similar to those obtained from other H i surveys. We also obtain stellar masses for 92 of the 148 robustly measured galaxies using multiband photometry through Dark Energy Sky Instrument Legacy Imaging Survey Data Release 10 images. We use a subset of 61 of these galaxies that have consistent optical and kinematic inclinations to examine the stellar and baryonic Tully–Fisher relations as well as the gas fraction–disk stability and gas fraction–baryonic mass relations. These measurements and relations demonstrate the unprecedented resource that WALLABY will represent for resolved galaxy scaling relations in H i. [ABSTRACT FROM AUTHOR]

This paper argues that we ought to conceive of the Dark Energy problem—the question of how to account for observational data, naturally interpreted as accelerated expansion of the universe—as a crisis of underdetermined pursuit-worthiness. Not only are the various approaches to the Dark Energy problem evidentially underdetermined; at present, no compelling reasons single out any of them as more likely to be true than the other. More vexingly for working scientists, none of the approaches stands out as uncontroversially preferable over its rivals in terms of its rationally warranted promise, i.e. the reasons to further work on, explore, and develop it. We demonstrate this claim by applying a Peircean economic model of pursuit-worthiness in terms of a cognitive cost/benefit estimate—with the instantiation of theory virtues as key indicators of cognitive gains—to the four main Dark Energy proposals (the cosmological constant approach, modified gravity, quintessence, and inhomogeneous cosmologies). According to our analysis, these approaches do not admit of an unambiguous, or uncontroversial, ranking with respect to which ansatz deserves distinguished attention and research efforts. The overall methodological counsel that our analysis underwrites recommends a pragmatic double research strategy forward: to encourage and foster theory pluralism and the search for tests—with the goal of enhancing the testability of the CDM model and “testing it to destruction". [ABSTRACT FROM AUTHOR]

The essay begins by recalling the words of Homer that to live is to behold the light of the sun. For it is the 'elementals' of sky, sun, and light that give all things to mortal beings, including time itself, beginning with the daily alternation between day and night. But contemporary commercial and scientific projects threaten to change all this. Whether it be through the launching of tens of thousands of communication satellites to fill the night sky or the creation of a sulfuric blanket in the atmosphere to block the sun's rays to combat global warming, what is threatened is our very relationship to the sun and to light. The essay thus argues that what is today needed is a new 'politics of light', one that would guard the clarity of the sky. Needed as well is a philosophy that attends to things beyond the human life-world, to the elementals of sun, sky, and light, but also to the invisibility at the heart of light itself. Appealing to some of the most recent scientific discoveries regarding the hyper-giganticness of the cosmos, the essay concludes that philosophy must attend to 'phenomena' whose nature is precisely to remain concealed, phenomena such as black holes, dark matter, and dark energy that are today thought to comprise an astonishing 95% of the matter and energy of the universe. Turned in this direction, the essay concludes, philosophy can perhaps reawaken the wonder that is at its very origin. [ABSTRACT FROM AUTHOR]

Upcoming Large Scale Structure surveys aim to achieve an unprecedented level of precision in measuring galaxy clustering. However, accurately modelling these statistics may require theoretical templates that go beyond two-loop order perturbation theory, especially for achieving precision at smaller scales. In our previous work, we introduced a hybrid model for the redshift space power spectrum of galaxies. This model combines two-loop order templates with N -body simulations to capture the influence of scale-independent parameters on the galaxy power spectrum. However, the impact of scale-dependent parameters was addressed by pre-computing a set of input statistics derived from computationally expensive N -body simulations. As a result, exploring the scale-dependent parameter space was not feasible in this approach. To address this challenge, we present an accelerated methodology that utilizes Gaussian Processes, a machine-learning technique, to emulate these input statistics. Our emulators exhibit remarkable accuracy, achieving reliable results with just 13 N -body simulations for training. Our emulators can reproduce the set of statistics we are interested in with less than 0.1 per cent error in the parameter space within |$5\sigma$| of the Planck Lambda cold dark matter predictions, specifically for scales around |$k \gt 0.1$|   h  Mpc |$^{-1}$|⁠. Following the training of our emulators, we can predict all inputs for our hybrid model in approximately 0.2 s at a specified redshift. Given that performing 13 N -body simulations is a manageable task, our present methodology enables us to construct efficient and highly accurate models of the galaxy power spectra within a manageable time frame. [ABSTRACT FROM AUTHOR]

Being the most prominent H  i line, Ly |$\alpha$| permeates the cosmic web in emission. Despite its potential as a cosmological probe, its detection on large scales remains elusive. We present a new methodology to perform Ly |$\alpha$| intensity mapping with broad-band optical images, by cross-correlating them with Ly |$\alpha$| forest data using a custom one-parameter estimator. We also develop an analytical large-scale Ly |$\alpha$| emission model with two parameters (average luminosity |$\langle L_{\rm Ly\alpha } \rangle$| and bias |$b_{\rm e}$|⁠) that respects observational constraints from quasar (QSO) luminosity functions. We compute a forecast for Dark Energy Camera Legacy Survey (DECaLS)/Beijing–Arizona Sky Survey (BASS) g -band images cross-correlated with Dark Energy Spectroscopic Instrument (DESI) Ly |$\alpha$| forest data, setting guidelines for reducing images into Ly |$\alpha$| intensity maps. Given the transversal scales of our cross-correlation (26.4 arcmin, |$\sim$| 33 cMpc h−1), our study effectively integrates Ly |$\alpha$| emission over all the cosmic volume inside the DESI footprint at |$2.2 \lt z \lt 3.4$| (the g -band Ly |$\alpha$| redshift range). Over the parameter space (⁠|$\langle L_{\rm Ly\alpha } \rangle$|⁠ , |$b_{\rm e}$|⁠) sampled by our forecast, we find a 3 |$\sigma$| of large-scale structure in Ly |$\alpha$| likely, with a probability of detection of 23.95 per cent for DESI–DECaLS/BASS, and 54.93 per cent for a hypothetical DESI phase-II with twice as much Ly |$\alpha$| QSOs. Without a detection, we derive upper bounds on |$\langle L_{\rm Ly\alpha } \rangle$| competitive with optimistic literature estimates [ |$2.3 \pm 1 \times 10^{\rm 41}$| erg s−1 (cMpc |$^3$|⁠)−1 for DESI, and |$\sim$| 35  per cent lower for its hypothetical phase-II]. Extrapolation to the DESI-Rubin overlap shows that a detection of large-scale structure with Ly |$\alpha$| intensity mapping using next-generation imaging surveys is certain. Such detection would allow constraining |$\langle L_{\rm Ly\alpha } \rangle$|⁠ , and explore the constraining power of Ly |$\alpha$| intensity mapping as a cosmological probe. [ABSTRACT FROM AUTHOR]

In this work, we present a method for numerically solving the Friedmann equations of modified |$f(\mathcal {G})$| gravity in the presence of pressureless matter. This method enables us to predict the redshift behaviour of the Hubble expansion rate. To evaluate the credibility of the model, we applied a Bayesian MCMC technique using late-time cosmic observations to impose limitations on the free parameters of the Gauss–Bonnet model. Our results suggest that the |$f(\mathcal {G})$| model can reproduce the low-redshift behaviour of the standard Lambda cold dark matter (⁠|$\Lambda$| CDM) model, but there are significant differences at high redshifts, leading to the absence of a standard matter-dominated epoch. We also examined the profiles of cosmographic parameters using the model parameter values from the standard range to verify the intermediate epochs. Our analysis shows that the highly promising |$f(\mathcal {G})$| model is a feasible candidate for explaining the current epochs. We presented a dynamical system analysis framework to examine the stability of the model. Our study identified critical points depicting various phases of the Universe and explained the evolutionary epochs. We demonstrated that the model effectively captures the evolution of energy components over cosmic time, supporting its validity as an alternate explanation for the observed acceleration of the Universe. [ABSTRACT FROM AUTHOR]

The Early Data Release (EDR) of the Dark Energy Spectroscopic Instrument (DESI) comprises spectroscopy obtained from 2020 December 14 to 2021 June 10. White dwarfs were targeted by DESI both as calibration sources and as science targets and were selected based on Gaia photometry and astrometry. Here, we present the DESI EDR white dwarf catalogue, which includes 2706 spectroscopically confirmed white dwarfs of which approximately 60 per cent have been spectroscopically observed for the first time, as well as 66 white dwarf binary systems. We provide spectral classifications for all white dwarfs, and discuss their distribution within the Gaia Hertzsprung–Russell diagram. We provide atmospheric parameters derived from spectroscopic and photometric fits for white dwarfs with pure hydrogen or helium photospheres, a mixture of those two, and white dwarfs displaying carbon features in their spectra. We also discuss the less abundant systems in the sample, such as those with magnetic fields, and cataclysmic variables. The DESI EDR white dwarf sample is significantly less biased than the sample observed by the Sloan Digital Sky Survey, which is skewed to bluer and therefore hotter white dwarfs, making DESI more complete and suitable for performing statistical studies of white dwarfs. [ABSTRACT FROM AUTHOR]

We present a novel approach to extracting dwarf galaxies from photometric data to measure their average halo mass profile with weak lensing. We characterize their stellar mass and redshift distributions with a spectroscopic calibration sample. By combining the |${\sim} 5000\,\mathrm{deg}^2$| multiband photometry from the Dark Energy Survey and redshifts from the Satellites Around Galactic Analogs Survey with an unsupervised machine learning method, we select a low-mass galaxy sample spanning redshifts |$z\lt 0.3$| and divide it into three mass bins. From low to high median mass, the bins contain [146 420, 330 146, 275 028] galaxies and have median stellar masses of |$\log _{10}(M_*/\text{M}_\odot)=\left[8.52\substack{+0.57 -0.76},\, 9.02\substack{+0.50 -0.64},\, 9.49\substack{+0.50 -0.58}\right]$|  . We measure the stacked excess surface mass density profiles, |$\Delta \Sigma (R)$|⁠ , of these galaxies using galaxy–galaxy lensing with a signal-to-noise ratio of [14, 23, 28]. Through a simulation-based forward-modelling approach, we fit the measurements to constrain the stellar-to-halo mass relation and find the median halo mass of these samples to be |$\log _{10}(M_{\rm halo}/\text{M}_\odot)$| = [ |$10.67\substack{+0.2 -0.4}$|⁠ ,  |$11.01\substack{+0.14 -0.27}$|⁠ ,  |$11.40\substack{+0.08 -0.15}$| ]. The cold dark matter profiles are consistent with NFW (Navarro, Frenk, and White) profiles over scales |${\lesssim} 0.15 \, {h}^{-1}$|  Mpc. We find that |${\sim} 20$| per cent of the dwarf galaxy sample are satellites. This is the first measurement of the halo profiles and masses of such a comprehensive, low-mass galaxy sample. The techniques presented here pave the way for extracting and analysing even lower mass dwarf galaxies and for more finely splitting galaxies by their properties with future photometric and spectroscopic survey data. [ABSTRACT FROM AUTHOR]

The recent results from the first-year baryon acoustic oscillations (BAO) data released by the Dark Energy Spectroscopic Instrument (DESI), combined with cosmic microwave background (CMB) and Type Ia supernova (SN) data, have shown a detection of significant deviation from a cosmological constant for dark energy. In this work, we utilize the latest DESI BAO data in combination with the SN data from the full 5 yr observations of the Dark Energy Survey and the CMB data from the Planck satellite to explore potential interactions between dark energy and dark matter. We consider four typical forms of the interaction term Q. Our findings suggest that interacting dark energy (IDE) models with Q ∝ ρ de support the presence of an interaction where dark energy decays into dark matter. Specifically, the deviation from ΛCDM for the IDE model with Q = β H 0 ρ de reaches the 3 σ level. These models yield a lower value of Akaike information criterion than the ΛCDM model, indicating a preference for these IDE models based on the current observational data. For IDE models with Q ∝ ρ c, the existence of interaction depends on the form of the proportionality coefficient Γ. The IDE model with Q = β H ρ c yields β = 0.0003 ± 0.0011, which essentially does not support the presence of the interaction. In general, whether the observational data support the existence of interaction is closely related to the model. Our analysis helps to elucidate which type of IDE model can better explain the current observational data. [ABSTRACT FROM AUTHOR]

The Dark Energy Spectroscopic Instrument (DESI) collaboration recently released its first year of data (DR1) on baryon acoustic oscillations (BAO) in galaxy, quasar, and Lyman- |$\alpha$| forest tracers. When combined with cosmic microwave background (CMB) and Type Ia supernovae (SNIa) data, DESI BAO results suggest potential thawing behaviour in dark energy. Cosmological analyses utilize comoving distances along (⁠|$D_\mathrm{ H}$|⁠) and perpendicular to (⁠|$D_\mathrm{ M}$|⁠) the line of sight. Notably, there are |$1\sim 2\sigma$| deviations in |$D_\mathrm{ M}$| and |$D_\mathrm{ H}$| from Planck cosmology values in the luminous red galaxies (LRG) bins LRG1 and LRG2.This study examines the role of LRG1 and LRG2 in diverging DESI 2024 BAO cosmology from Planck cosmology. We use angle-averaged distance |$D_\mathrm{ V}$| and the ratio |$F_{\rm AP}=D_\mathrm{ M}/D_\mathrm{ H}$|⁠ , which are more directly related to the measured monopole and quadrupole components of the galaxy power spectrum or correlation function, instead of the officially adopted |$D_\mathrm{ M}$| and |$D_\mathrm{ H}$|⁠. This transformation aims to isolate the influence of monopoles in LRG1 and LRG2 on deviations from |$w=-1$|⁠. Our findings indicate that removing the |$D_\mathrm{ V}$| data point in LRG2 aligns DESI + CMB + SNIa data compilation with |$w=-1$| within a |$2\sigma$| contour and reduces the |$H_0$| discrepancy from the Planck 2018 results from |$0.63\sigma$| to |$0.31\sigma$|⁠. Similarly, excluding the |$D_\mathrm{ V}$| data point from LRG1 shifts the |$w_0/w_a$| contour toward |$w=-1$|⁠ , although no intersection occurs. This highlights the preference of both LRG1 and LRG2 BAO monopole components for the thawing dark energy model, with LRG2 showing a stronger preference. We provide the |$D_\mathrm{ V}$| and |$F_{\rm AP}$| data and their covariance alongside this paper. [ABSTRACT FROM AUTHOR]

We explore correlations between the orientations of small galaxy groups, or 'multiplets', and the large-scale gravitational tidal field. Using data from the Dark Energy Spectroscopic Instrument (DESI) Y1 survey, we detect the intrinsic alignment (IA) of multiplets to the galaxy-traced matter field out to separations of |$100\,h^{-1}$|  Mpc. Unlike traditional IA measurements of individual galaxies, this estimator is not limited by imaging of galaxy shapes and allows for direct IA detection beyond redshift |$z=1$|⁠. Multiplet alignment is a form of higher order clustering, for which the scale-dependence traces the underlying tidal field and amplitude is a result of small-scale (⁠|$\lt 1h^{-1}$|  Mpc) dynamics. Within samples of bright galaxies, luminous red galaxies (LRG) and emission-line galaxies, we find similar scale-dependence regardless of intrinsic luminosity or colour. This is promising for measuring tidal alignment in galaxy samples that typically display no IA. DESI's LRG mock galaxy catalogues created from the A  bacus S  ummit N -body simulations produce a similar alignment signal, though with a 33 per cent lower amplitude at all scales. An analytic model using a non-linear power spectrum (NLA) only matches the signal down to 20  |$h^{-1}$|  Mpc. Our detection demonstrates that galaxy clustering in the non-linear regime of structure formation preserves an interpretable memory of the large-scale tidal field. Multiplet alignment complements traditional two-point measurements by retaining directional information imprinted by tidal forces, and contains additional line-of-sight information compared to weak lensing. This is a more effective estimator than the alignment of individual galaxies in dense, blue, or faint galaxy samples. [ABSTRACT FROM AUTHOR]

In this study, we investigate the Barrow holographic dark energy (BHDE) model with the Granda–Oliveros(G–O) infrared (IR) cut-off in the presence of neutrino masses, utilizing the latest observational data to address the Hubble tension. The GO cut-off is defined as |$L_{\mathrm{ IR}}=(\alpha H^2 + \beta \dot{H})^{-1/2}$|⁠. We place constraints on the total neutrino mass |$\sum m_{\nu }$| using data from Type Ia supernovae (SN) Pantheon, cosmic chronometers (CC), cosmic microwave background (CMB), Baryon Acoustic Oscillation (BAO) data sets, and Planck Lensing. Specifically, the comprehensive CMB + BAO + CC + Pantheon data set provides a total neutrino mass of |$0.118\, \text{eV}$|⁠. The parameters for the Barrow-GO model are determined to be |$\Delta = 0.0055^{+0.0086}_{-0.0086}$|⁠ , |$\alpha = 0.997^{+0.060}_{-0.060}$|⁠ , and |$\beta = 0.598^{+0.080}_{-0.080}$|⁠ , showing good agreement with previous studies. One of the key findings of this study is the model's ability to alleviate the Hubble tension, as evidenced by the comparison of |$H_0$| measurements. Specifically, the tension value for the combination of data set (CMB + BAO + CC + Pantheon + Lensing) is |$1.5\sigma$| with the Planck 2018 and |$1.4\sigma$| with R22. These results underscore the importance of multi-data set integration in refining constraints on neutrino properties and highlight the model's efficacy in probing fundamental aspects of neutrino physics. Our results demonstrate that the BHDE model with the GO cut-off can effectively address the Hubble tension, offering a coherent framework that reconciles local and cosmological measurements of the Hubble constant. [ABSTRACT FROM AUTHOR]

We analyse the fourth data release of the Kilo Degree Survey (KiDS-1000) and extract cosmological parameter constraints based on the cosmic shear peak count statistics. Peaks are identified in aperture mass maps in which the filter is maximally sensitive to angular scales in the range 2–4 arcmin, probing deep into the non-linear regime of structure formation. We interpret our results with a simulation-based inference pipeline, sampling over a broad w CDM prior volume and marginalizing over uncertainties on shape calibration, photometric redshift distribution, intrinsic alignment, and baryonic feedback. Our measurements constrain the structure growth parameter and the amplitude of the non-linear intrinsic alignment model to |$\Sigma _8 \equiv \sigma _8\left[\Omega _{\rm m}/0.3\right]^{0.60}=0.765^{+0.030}_{-0.030}$| and |$A_{\rm IA}= 0.71^{+0.42}_{-0.42}$|⁠ , respectively, in agreement with previous KiDS-1000 results based on two-point shear statistics. These results are robust against modelling of the non-linear physics, different scale cuts, and selections of tomographic bins. The posterior is also consistent with that from the Dark Energy Survey Year-1 peak count analysis presented in Harnois-Déraps et al. and hence we jointly analyse both surveys with a common pipeline. We obtain |$\Sigma _8^{\rm joint} \equiv \sigma _8\left[\Omega _{\rm m}/0.3\right]^{0.57}=0.759^{+0.020}_{-0.017}$|⁠ , in agreement with the Planckw CDM results. The shear-CMB tension on this parameter increases to |$3.1\sigma$| when forcing |$w=-1.0$|⁠ , and to |$4.1\sigma$| if comparing instead with |$S_{8,\Lambda {\rm CDM}}^{\rm joint} = 0.736^{+0.016}_{-0.018}$|⁠ , one of the tightest constraints to date on this quantity. Residual biases in the photometric redshifts of the DES-Y1 data and in the modelling of small scales physics could lower this tension, however it is robust against other systematics. Limits in the accuracy of our emulator prevent us from constraining |$\Omega _{\rm m}$|⁠. [ABSTRACT FROM AUTHOR]

The Weyl potential, which is the sum of the spatial and temporal distortions of the Universe's geometry, provides a direct way of testing the theory of gravity and the validity of the ΛCDM (Lambda Cold Dark Matter) model. Here we present measurement of the Weyl potential at four redshifts bins using data from the first three years of observations of the Dark Energy Survey. We find that the measured Weyl potential is 2 σ, respectively 2.8 σ, below the ΛCDM predictions in the two lowest redshift bins. We show that these low values of the Weyl potential are at the origin of the tension between Cosmic Microwave Background measurements and weak lensing measurements, regarding the parameter σ8 which quantifies the clustering of matter. Interestingly, we find that the tension remains if no information from the Cosmic Microwave Background is used. Dark Energy Survey data on their own prefer a high value of the primordial fluctuations, together with a slow evolution of the Weyl potential. An important feature of our method is that the measurements of the Weyl potential are model-independent and can therefore be confronted with any theory of gravity, allowing efficient tests of models beyond General Relativity. The Weyl potential provides a direct way of testing the theory of gravity and the validity of the ΛCDM model. Here, the authors show Weyl potential measured at four redshifts bins and find that the measured values in the two lowest bins are in mild tension with the ΛCDM predictions. [ABSTRACT FROM AUTHOR]

We are merging a large participatory science effort with machine learning to enhance the Hobby–Eberly Telescope Dark Energy Experiment (HETDEX). Our overall goal is to remove false positives, allowing us to use lower signal-to-noise data and sources with low goodness-of-fit. With six million classifications through Dark Energy Explorers, we can confidently determine if a source is not real at over 94% confidence level when classified by at least 10 individuals; this confidence level increases for higher signal-to-noise sources. To date, we have only been able to apply this direct analysis to 190,000 sources. The full sample of HETDEX will contain around 2–3 million sources, including nearby galaxies ([O ii ] emitters), distant galaxies (Ly α emitters or LAEs), false positives, and contamination from instrument issues. We can accommodate this tenfold increase by using machine learning with visually vetted samples from Dark Energy Explorers. We have already increased by over tenfold the number of sources that have been visually vetted from our previous pilot study where we only had 14,000 visually vetted LAE candidates. This paper expands on the previous work by increasing the visually vetted sample from 14,000 to 190,000. In addition, using our currently visually vetted sample, we generate a real or false positive classification for the full candidate sample of 1.2 million LAEs. We currently have approximately 17,000 volunteers from 159 countries around the world. Thus, we are applying participatory or citizen scientist analysis to our full HETDEX data set, creating a free educational opportunity that requires no prior technical knowledge. [ABSTRACT FROM AUTHOR]

In this paper, we considered four observationally constrained, one-parameter dark energy models to see their plausible impacts on the tidal ellipticity and related statistics of cosmic voids. Our main question is to see if different models of dark energy could be distinguished through ellipticity of cosmic voids. In this way, we employed an analytic method on the base of local tidal tensor. In this method, the center of a void is located at local minimum of the linear density field. At first, we obtained the effect of the one-parameter DE models on the distribution function of the cosmic voids and simultaneously compared the results with the standard cosmology (ΛCDM). We found that the distribution function of these models is different with respect to that of ΛCDM. In addition, we obtained the mean ellipticity of cosmic voids, 〈ε〉, against redshift and found that in all models the 〈ε〉 as well as εmax has a decaying trend. Besides, we considered the mean ellipticity evolution versus the smoothing scale of voids (RL). We found that the differences between dark energy models are significantly discernible via the ellipticity evolution versus the void scale (RL). We saw that the studied models result in different ellipticity evolutions (versus RL) up to 5% smaller with respect to that of the ΛCDM. [ABSTRACT FROM AUTHOR]

We point out that dark matter and dark energy arise naturally in a recently proposed model of combinatorial quantum gravity. Dark energy is due to the ground-state curvature at finite coupling, dark matter arises from allotropy in the discrete structure of space-time. The stable structure of the space-time 'crystal' represents the curved background, the coexisting metastable allotropes of higher curvature and energy are natural candidates for dark matter. We thus suggest that dark energy and dark matter are two manifestation of quantum gravity. [ABSTRACT FROM AUTHOR]

Context. Stellar tidal streams are a key tracer of galaxy evolution and have the potential to provide an indirect means for tracing dark matter. For the Local Group, many diffuse substructures have been identified and their link to galaxy evolution has been traced. However, the Local Group does not offer a statistically significant sample of stellar tidal streams. Thus, an analysis of a larger sample beyond the Local Group is required to better probe the frequency and characteristics of these streams to verify whether these properties are in agreement with the predictions of the ΛCDM model and its implementation in cosmological simulations, taking into account the impact of the baryonic physics modelling. Aims. The main scope of the Stellar Stream Legacy Survey is to obtain a statistically significant sample of stellar streams in the local Universe to be able to trace and study minor mergers and their contribution to galaxy evolution with respect to the ΛCDM theory. For that purpose, we are carrying out the first systematic survey of faint stellar debris from tidally disrupted dwarf satellites around nearby galaxies up to a distance of 100 Mpc. Methods. In this paper, we present a catalogue with the results of the first harvest of stellar tidal streams found by visual inspection in deep images of ∼700 galaxies from the Dark Energy Survey (DES). We also include, for the first time, a photometric characterisation of the streams obtained by measuring their surface brightnesses and colours. Results. We found a total of 63 streams in our sample at distances between 40 and 100 Mpc, including 58 that were not previously reported. We measured their average surface brightness for the g band, the r band and the z band, to be 28.35 ± 0.20, 27.81 ± 0.13, and 27.62 ± 0.09 mag arcsec−2, respectively. By applying a statistical analysis to our findings, we obtained a stream detection frequency of 9.1% ± 1.1% for the given surface brightness limit of the DES image sample, in agreement with previous studies. We identified stream progenitors in 5–14% of our stream sample, depending on the confidence level. Conclusions. The first catalogue of streams in the local Universe presented here will be complemented by future stream surveys within the Stellar Stream Legacy Survey and can be exploited in studies pertaining to galaxy evolution and cosmological models. In this work, we have learnt that the faintest measured stream surface brightness can be significantly brighter than the surface brightness limit of an image measured at the pixel level (in our case up to ∼1 mag arcsec−2 for the r band) mainly due to correlated noise present in the images. [ABSTRACT FROM AUTHOR]

In this article, we focus on the complex relationship between the shape of dark matter (DM) halos and the cosmological models underlying their formation. We have used three realistic cosmological models from the DEUS numerical simulation project. These three models have very distinct cosmological parameters (Ωm, σ8, and w) but their cosmic matter fields beyond the scale of DM halos are quasi-indistinguishable, providing an exemplary framework to examine the cosmological dependence of DM halo morphology. First, we developed a robust method for measuring the halo shapes detected in numerical simulations. This method avoids numerical artifacts on DM halo shape measurements, induced by the presence of substructures depending on the numerical resolution or by any spherical prior that does not respect the triaxiality of DM halos. We then obtain a marked dependence of the halo's shape both on their mass and the cosmological model underlying their formation. As it is well known, the more massive the DM halo, the less spherical it is and we find that the higher the σ8 of the cosmological model, the more spherical the DM halos. Then, by reexpressing the properties of the shape of the halos in terms of the nonlinear fluctuations of the total cosmic matter field or only of the cosmic matter field which is internal to the halos, we managed to make the cosmological dependence disappear completely. This new fundamental cosmological invariance is a direct consequence of the nonlinear dynamics of the cosmic matter field. As the universe evolves, the nonlinear fluctuations of the cosmic field increase, driving the dense matter halos toward sphericity. The deviation from sphericity, measured by the prolaticity, triaxiality, and ellipticity of the DM halos, is therefore entirely encapsulated in the nonlinear power spectrum of the cosmic field. From this fundamental invariant relation, we retrieve with remarkable accuracy the root-mean-square of the nonlinear fluctuations and, consequently, the power spectrum of the cosmic matter field in which the halos formed. We also recover the σ8 amplitude of the cosmological model that governs the cosmic matter field at the origin of the DM halos. Our results therefore highlight, not only the nuanced relationship between DM halo formation and the underlying cosmology but also the potential of DM halo shape analysis of being a powerful tool for probing the nonlinear dynamics of the cosmic matter field. [ABSTRACT FROM AUTHOR]

Aims. Calibrating the point spread function (PSF) is a fundamental part of weak gravitational lensing analyses. Even with corrected galaxy images, imperfect calibrations can introduce biases. We propose an analytical framework for quantifying PSF-induced systematics as diagnostics for cross-correlation measurements of weak lensing with density tracers; for example, galaxy-galaxy lensing. We show how those systematics propagate to physical parameters of the density tracers. Those diagnostics only require a shape catalog of PSF stars and foreground galaxy positions. Methods. We considered the PSF-induced multiplicative bias, and introduced three second-order statistics as additive biases. We computed both biases for the weak-lensing derived halo mass of spectroscopic foreground galaxy samples; in particular, their effect on the tangential shear and fit halo mass as a function of stellar mass. In addition, we assessed their impact on the recently published black-hole – halo-mass relation for type I active galactic nuclei (AGNs). Results. Using weak-lensing catalogs from the Ultraviolet Near Infrared Optical Northern Survey (UNIONS) and the Dark Energy Survey (DES), we find the multiplicative biases in the tangential shear to be less than 0.5%. No correlations between additive bias and galaxy properties of the foreground sample are detected. The combined PSF systematics affect low-mass galaxies and small angular scales; halo mass estimates can be biased by up to 18% for a sample of central galaxies in the stellar mass range of 9.0 ≤ log M*/M⊙ < 9.5. Conclusions. The PSF-induced multiplicative bias is a subdominant contribution to current studies of weak-lensing – density cross-correlations, but might become significant for upcoming stage IV surveys. For samples with a low tangential shear, additive PSF systematics can induce a significant bias on derived properties such as the halo mass. [ABSTRACT FROM AUTHOR]

Aims. We present the discovery of an extended and faint tail observed in the isolated environment associated with galaxy NGC 3785. This study additionally provides observational evidence supporting the formation of ultra-diffuse galaxies (UDGs) at the end of the tail. Methods. We utilized the Gnuastro software to detect and analyze the low surface brightness structures in the optical g- and r-bands using data from the Dark Energy Camera Legacy Survey. We created a detection map to identify the faint tail and measured its length using cubic spline fitting. Additionally, we found 84 star-forming clumps along the tail and performed photometric analysis on the tail portion after applying a significance threshold on the signal-to-noise ratio. Results. We have measured the projected length of the tail, which is ∼390 kpc. We propose that this tail arises from the interaction of the NGC 3785 with a gas-rich galaxy, which ends up as a UDG at the end of the tail. [ABSTRACT FROM AUTHOR]

Cosmological information is usually extracted from the Lyman- |$\alpha$| (Ly  |$\alpha$|⁠) forest correlations using only either large-scale information interpreted through linear theory or using small-scale information interpreted by means of expensive hydrodynamical simulations. A complete cosmological interpretation of the three-dimensional (3D) correlations at all measurable scales is challenged by the need of more realistic models including the complex growth of non-linear small scales that can only be studied within large hydrodynamical simulations. Past works were often limited by the trade-off between the simulated cosmological volume and the resolution of the low-density intergalactic medium from which the Ly  |$\alpha$| signal originates. We conduct a suite of hydrodynamical simulations of the intergalactic medium, including one of the largest Ly  |$\alpha$| simulations ever performed in terms of volume (640 |$\, h^{-1}\, \mathrm{Mpc}$|⁠), alongside simulations in smaller volumes with resolutions up to 25 |$\, h^{-1}\, \mathrm{kpc}$|⁠ , which will be further improved to show resolution convergence in future studies. We compare the 3D Ly  |$\alpha$| power spectra (⁠|$P_{3\mathrm{D},\alpha }$|⁠) predicted by those simulations to different non-linear models. The inferred Ly  |$\alpha$| bias and redshift space distortion parameters, |$b_\alpha$| and |$\beta _\alpha$| are in remarkable agreement with those measured in SDSS (Sloan Digital Sky Survey) and DESI (Dark Energy Spectroscopic Instrument) data. We find that, contrary to intuition, the convergence of large-scale modes of the |$P_{3\mathrm{D},\alpha }$|⁠ , which determines |$\beta _\alpha$|⁠ , is primarily influenced by the resolution of the simulation box through mode coupling, rather than the box size itself. Finally, we study the Baryon Acoustic Oscillation (BAO) signal encoded in |$P_{3\mathrm{D},\alpha }$|⁠. For the first time with a hydrodynamical simulation, we clearly detect the BAO signal; however, we only marginally detect its damping, associated with the non-linear growth of the structures. [ABSTRACT FROM AUTHOR]

Studies have shown that the morphologies of galaxies are substantially transformed following coalescence after a merger, but post-mergers are notoriously difficult to identify, especially in imaging that is shallow or low resolution. We train convolutional neural networks (CNNs) to identify simulated post-merger galaxies in a range of image qualities, modelled after five real surveys: the Sloan Digital Sky Survey (SDSS), the Dark Energy Camera Legacy Survey (DECaLS), the Canada–France Imaging Survey (CFIS), the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP), and the Legacy Survey of Space and Time (LSST). Holding constant all variables other than imaging quality, we present the performance of the CNNs on reserved test set data for each image quality. The success of CNNs on a given data set is found to be sensitive to both imaging depth and resolution. We find that post-merger recovery generally increases with depth, but that limiting 5 |$\sigma$| point-source depths in excess of |$\sim 25$| mag, similar to what is achieved in CFIS, are only marginally beneficial. Finally, we present the results of a cross-survey inference experiment, and find that CNNs trained on a given image quality can sometimes be applied to different imaging data to good effect. The work presented here therefore represents a useful reference for the application of CNNs for merger searches in both current and future imaging surveys. [ABSTRACT FROM AUTHOR]

We present an in-depth investigation of galaxy clustering based on a new suite of realistic large-box galaxy formation simulations in |$f(R)$| gravity, with a subgrid physics model that has been recalibrated to reproduce various observed stellar and gas properties. We focus on the two-point correlation functions of the luminous red galaxies (LRGs) and emission line galaxies (ELGs), which are primary targets of ongoing and future galaxy surveys such as Dark Energy Spectroscopic Instrument (DESI). One surprising result is that, due to several non-trivial effects of modified gravity on matter clustering and the galaxy–halo connection, the clustering signal does not depend monotonically on the fifth-force strength. For LRGs, this complicated behaviour poses a challenge to meaningfully constraining this model. For ELGs, in contrast, this can be straightforwardly explained by the time evolution of the fifth force, which means that weaker |$f(R)$| models can display nearly the same – up to 25 per cent – deviations from Lambda cold dark matter model as the strongest ones, albeit at lower redshifts. This implies that even very weak |$f(R)$| models can be strongly constrained, unlike with most other observations. Our results show that galaxy formation acquires a significant environment dependence in |$f(R)$| gravity, which, if not properly accounted for, may lead to biased constraints on the model. This highlights the essential role of hydrodynamical simulations in future tests of gravity exploring precision galaxy-clustering data from the likes of DESI and Euclid. [ABSTRACT FROM AUTHOR]

Low-density cosmic voids gravitationally lens the cosmic microwave background (CMB), leaving a negative imprint on the CMB convergence |$\kappa$|⁠. This effect provides insight into the distribution of matter within voids, and can also be used to study the growth of structure. We measure this lensing imprint by cross-correlating the Planck CMB lensing convergence map with voids identified in the Dark Energy Survey Year 3 (DES Y3) data set, covering approximately 4200 deg |$^2$| of the sky. We use two distinct void-finding algorithms: a 2D void-finder that operates on the projected galaxy density field in thin redshift shells, and a new code, Voxel , which operates on the full 3D map of galaxy positions. We employ an optimal matched filtering method for cross-correlation, using the Marenostrum Institut de Ciències de l'Espai N -body simulation both to establish the template for the matched filter and to calibrate detection significances. Using the DES Y3 photometric luminous red galaxy sample, we measure |$A_\kappa$|⁠ , the amplitude of the observed lensing signal relative to the simulation template, obtaining |$A_\kappa = 1.03 \pm 0.22$| (⁠|$4.6\sigma$| significance) for Voxel and |$A_\kappa = 1.02 \pm 0.17$| (⁠|$5.9\sigma$| significance) for 2D voids, both consistent with Lambda cold dark matter expectations. We additionally invert the 2D void-finding process to identify superclusters in the projected density field, for which we measure |$A_\kappa = 0.87 \pm 0.15$| (⁠|$5.9\sigma$| significance). The leading source of noise in our measurements is Planck noise, implying that data from the Atacama Cosmology Telescope, South Pole Telescope and CMB-S4 will increase sensitivity and allow for more precise measurements. [ABSTRACT FROM AUTHOR]

Type Ia Supernovae (SNe Ia) are a critical tool in measuring the accelerating expansion of the universe. Recent efforts to improve these standard candles have focused on incorporating the effects of dust on distance measurements with SNe Ia. In this paper, we use the state-of-the-art Dark Energy Survey 5 year sample to evaluate two different families of dust models: empirical extinction models derived from SNe Ia data and physical attenuation models from the spectra of galaxies. In this work, we use realistic simulations of SNe Ia to forward-model different models of dust and compare summary statistics in order to test different assumptions and impacts on SNe Ia data. Among the SNe Ia-derived models, we find that a logistic function of the total-to-selective extinction |$R_V$| best recreates the correlations between supernova distance measurements and host galaxy properties, though an additional 0.02 mag of grey scatter is needed to fully explain the scatter in SNIa brightness in all cases. These empirically derived extinction distributions are highly incompatible with the physical attenuation models from galactic spectral measurements. From these results, we conclude that SNe Ia must either preferentially select extreme ends of galactic dust distributions, or that the characterization of dust along the SNe Ia line-of-sight is incompatible with that of galactic dust distributions. [ABSTRACT FROM AUTHOR]

We assess the usefulness of gradient-based samplers, such as the no-U-turn sampler (NUTS), by comparison with traditional Metropolis–Hastings (MH) algorithms, in tomographic |$3\times 2$| point analyses. Specifically, we use the Dark Energy Survey (DES) Year 1 data and a simulated dataset for the Large Synoptic Survey Telescope (LSST) survey as representative examples of these studies, containing a significant number of nuisance parameters (20 and 32, respectively) that affect the performance of rejection-based samplers. To do so, we implement a differentiable forward model using jax-cosmo , and we use it to derive parameter constraints from both data sets using the nuts algorithm implemented in numpyro , and the Metropolis–Hastings algorithm as implemented in cobaya. When quantified in terms of the number of effective number of samples taken per likelihood evaluation, we find a relative efficiency gain of |$\mathcal {O}(10)$| in favour of NUTS. However, this efficiency is reduced to a factor |$\sim 2$| when quantified in terms of computational time, since we find the cost of the gradient computation (needed by nuts) relative to the likelihood to be |$\sim 4.5$| times larger for both experiments. We validate these results making use of analytical multivariate distributions (a multivariate Gaussian and a Rosenbrock distribution) with increasing dimensionality. Based on these results, we conclude that gradient-based samplers such as NUTS can be leveraged to sample high-dimensional parameter spaces in Cosmology, although the efficiency improvement is relatively mild for moderate (⁠|$\mathcal {O}(50)$|⁠) dimension numbers, typical of tomographic large-scale structure analyses. [ABSTRACT FROM AUTHOR]

We present griz photometric light curves for the full 5 yr of the Dark Energy Survey Supernova (DES-SN) program, obtained with both forced point-spread function photometry on difference images (DiffImg) performed during survey operations, and scene modelling photometry (SMP) on search images processed after the survey. This release contains 31,636 DiffImg and 19,706 high-quality SMP light curves, the latter of which contain 1635 photometrically classified SNe that pass cosmology quality cuts. This sample spans the largest redshift (z) range ever covered by a single SN survey (0.1 < z < 1.13) and is the largest single sample from a single instrument of SNe ever used for cosmological constraints. We describe in detail the improvements made to obtain the final DES-SN photometry and provide a comparison to what was used in the 3 yr DES-SN spectroscopically confirmed Type Ia SN sample. We also include a comparative analysis of the performance of the SMP photometry with respect to the real-time DiffImg forced photometry and find that SMP photometry is more precise, more accurate, and less sensitive to the host-galaxy surface brightness anomaly. The public release of the light curves and ancillary data can be found at github.com/des-science/DES-SN5YR and doi: 10.5281/zenodo.12720777. [ABSTRACT FROM AUTHOR]

This paper proposes a new model for anisotropic compact stars with quintessence in Rastall teleparallel gravity via embedding approach. In the gravity, the acquired field equations encompassing the anisotropic matter source as well as the quintessence field are studied using the specific character of the scalar torsion T for the observed stars candidates PSRJ 1416–2230, 4U 1608–52, CenX–3, EXO 1785–248 and SMC X–1. All of the stellar structures under consideration are said to be advantageously independent of any central singularity and are stable. A thorough graphical analysis reveals that numerous physical properties critical for forming stellar structures are satisfied. [ABSTRACT FROM AUTHOR]

In this paper, we have explored cold dark matter and holographic dark energy cosmological model with big rip singularity. To obtain the solution of the field equation, we supposed that scalar expansion is proportional to shear scalar σ 2 , which leads to P 1 = (P 2) n , where P 1 , P 2 are metric potentials and n is constant. Big bang and big rip singularity are investigated. The state-finder parameter is analyzed. The physical and geometrical parameters of the universe are explained. [ABSTRACT FROM AUTHOR]

This work reports a study on bounce cosmology with a highly generalized holographic dark fluid inspired by Nojiri and Odintsov [Eur. Phys. J. C 77 (2017) 1–8]. The holographic dark fluid that is mostly used for late-time acceleration has been implemented to reconstruct toward realization of cosmological bounce. We first used the most generalized Nojiri–Odintsov (NO) cutoff to implement the holographic dark fluid. Accordingly, we have reconstructed this dark fluid via some solutions of scale factors. With those solutions, we have explored the evolution of different cosmological parameters. We have examined the effects of each reconstructed parameter in the context of the realization of the cosmic bounce. Next, we use the analytical inferences of the scalar spectral index, tensor-to-scalar ratio, and slow-roll characteristics of the model to study a bounce inflationary scenario. Since inflation is usually associated with the existence of scalar fields, we looked at a possible relationship between NO generalized holographic dark energy and scalar field models. Plotting the evolution of the potential results from the scalar fields against time. Finally, we investigated the GSL of thermodynamics in the pre- and post-bounce scenarios. [ABSTRACT FROM AUTHOR]

This paper considers the only sectors to constitute the present universe as the dark matter and dark energy. The proposed new agegraphic dark energy model studies the gradual transition from matter to dark energy in sequential order, including the current dominance of the matter sector by dark energy. The model utilizes concepts of Tsallis entropy and the Karolyhazy relation with conformal time η as the time scale. Various evolutionary aspects of the universe are characterized by Tsallis parameter δ and the model constant c. Expressions for dynamic behavior of dark energy, as a differential equation, equation of state and deceleration parameters are obtained to describe the thermal history of universe evolution. Also, the stability of the model is analyzed through squared sound speed parameter. The analysis is made by considering an interaction as well as independence among the constituent sectors of the universe. [ABSTRACT FROM AUTHOR]

The article explains that the special theory of relativity (SRT), created in the early twentieth century, which is an outstanding scientific achievement, was ahead of its time, because in physics at that time lacked some knowledge necessary for its creation - physical reality of imaginary numbers was not proved and the its physical meaning was not explained, dark matter and dark energy were not discovered, discrete mathematics and hypercomplex numbers were not used, and WMAP and Planck space-crafts were not launched into space yet. Therefore absence of the mentioned knowledge was justifiably replaced by postulates. But not everything was guessed. And present now in the version of SRT studied in all physics textbooks, the postulate called the principle of nonexceeding the speed of light turned out to be incorrect. Therefore the corrected version of SRT in which this postulate is replaced by the experimentally proved principle of physical reality of imaginary numbers is offered. In this corrected version of SRT also offered a experimental proof of the existence of mutually invisible parallel universes astronomical observations in portals invisible outside the portals of constellations. And it is explained, why the principle of non-exceeding of speed of light not disproved so far by physical experiments is incorrect. And why the incorrect version of SRT, studied in all physics textbooks, is still in demand. [ABSTRACT FROM AUTHOR]

In this paper, we consider the single-parameter ℛ+cℛ2 gravitational action and use constraints from astrophysics and the laboratory to derive a natural relation between the coefficient c and the value of the cosmological constant. We find that the renormalization of c from the energy of the inflationary phase to the infrared, where the acceleration of the expansion of the universe takes place, is correlated with the evolution of the vacuum energy. Our results suggest that the coefficient of the ℛ2 term may provide an unexpected bridge between high-energy physics and cosmological phenomena such as inflation and dark energy. [ABSTRACT FROM AUTHOR]

In [1], we pointed out that in the Dark Dimension scenario [2] theoretical issues arise when the prediction for the vacuum energy ρ, that is obtained from swampland conjectures in string theory, is confronted with the corresponding result for ρ in the effective field theory (EFT) limit. One of the problems concerns the widely spread belief that in higher dimensional EFTs with compact dimensions the vacuum energy is automatically finite. On the contrary, our analysis shows that ρ contains (previously missed) UV-sensitive terms. Our work was challenged in [3]. Here we show why in our opinion the claims in [3] are flawed, and provide further support to our findings. We conclude presenting ideas on the physical mechanism that should dispose of the large UV contributions to ρ. [ABSTRACT FROM AUTHOR]

We present a detailed analysis of a new iterative density reconstruction algorithm. This algorithm uses a decreasing smoothing scale to better reconstruct the density field in Lagrangian space. We implement this algorithm to run on the quijote simulations, and extend it to (a) include a smoothing kernel that smoothly goes from anisotropic to isotropic, and (b) a variant that does not correct for redshift space distortions. We compare the performance of this algorithm with the standard reconstruction method. Our examinations of the methods include cross-correlation of the reconstructed density field with the linear density field, reconstructed two-point functions, and BAO parameter fitting. We also examine the impact of various parameters, such as smoothing scale, anisotropic smoothing, tracer type/bias, and the inclusion of second order perturbation theory. We find that the two reconstruction algorithms are comparable in most of the areas we examine. In particular, both algorithms give consistent fittings of BAO parameters. The fits are robust over a range of smoothing scales. We find the iterative algorithm is significantly better at removing redshift space distortions. The new algorithm will be a promising method to be employed in the ongoing and future large-scale structure surveys. [ABSTRACT FROM AUTHOR]

In this paper, our investigation focuses on the cosmic history in modified f(Q) gravity, a different theory that describes the gravitational force using a non-metricity scalar. The equations of the theory are solved by assuming a parametric form for the deceleration parameter. The parameters of the model are estimated by using the Cosmic Chronometer dataset. A number of parameters, like the deceleration parameter, whose signature changes with redshift and shows typical behavior in late-time cosmology, are subject of our analysis. We also show the evolution of other parameters, such as the equation of state parameter and energy density. The parametrization approach used here in f(Q) modified gravity provides a better description of the late-time cosmic evolution without dark energy. [ABSTRACT FROM AUTHOR]

We explore the influence of radio-mode feedback on the properties of the cool circumgalactic medium (CGM). To this end, we assemble a statistical sample of approximately 30,000 radio galaxies with background quasars by combining optical spectroscopic measurements of luminous red galaxies and quasars from the year 1 data set of the Dark Energy Spectroscopic Instrument and radio sources from the LOw-Frequency ARray Two-metre Sky Survey (LoTSS) DR2 catalog and the Very Large Array Sky Survey (VLASS) quick-look catalog. Galaxies with similar optical properties but with no radio counterparts in LoTSS and VLASS are selected as the control group. We measure the cool CGM properties of radio galaxies and their control samples traced by Mg ii absorption lines, including covering fraction, rest equivalent width, and gas kinematics. Our results show no significant difference in the properties of gas around radio galaxies and their control sample, indicating that the operating radio-mode feedback of massive galaxies does not produce detectable effects on the properties of the cool CGM. Finally, we show that the CGM of radio galaxies contains a nonnegligible amount of cool gas with approximately 1010 M ⊙. This abundance can place a stringent constraint on the radio-mode feedback models. [ABSTRACT FROM AUTHOR]

Flux excesses in the early-time light curves of Type Ia supernovae (SNe Ia) are predicted by multiple theoretical models and have been observed in a number of nearby SNe Ia over the last decade. However, the astrophysical processes that cause these excesses may affect their use as standardizable candles for cosmological parameter measurements. We perform a systematic search for early-time excesses in SNe Ia observed by the Zwicky Transient Facility (ZTF) to study whether SNe Ia with these excesses yield systematically different Hubble residuals. We analyze two compilations of SN Ia light curves from ZTF's first year of operations: 127 high-cadence light curves from Y. Yao et al. and 305 light curves from the ZTF cosmology data release of S. Dhawan et al. We detect significant early-time excesses for 17 SNe Ia in these samples and find that the excesses have a median g − r color of 0.10 ± 0.11 mag; we do not find a clear preference for blue excesses as predicted by several models. Using the SALT3 model, we measure Hubble residuals for these two samples, finding that excess-having SNe Ia may have lower Hubble residuals (HR) after correcting for shape, color, and host-galaxy mass, at ∼2–3 σ significance; our baseline result is ΔHR = −0.056 ± 0.026 mag (2.2 σ). We compare the host-galaxy masses of excess-having and no-excess SNe Ia and find they are consistent, though at marginal significance excess-having SNe Ia may prefer lower-mass hosts. Additional discoveries of early excess SNe Ia will be a powerful way to understand potential biases in SN Ia cosmology and probe the physics of SN Ia progenitors. [ABSTRACT FROM AUTHOR]

In the emerging era of big data astrophysics, large-scale extragalactic surveys will soon provide high-quality imaging for billions of celestial objects to answer major questions in astrophysics such as the nature of dark matter and dark energy. Precision cosmology with surveys requires accurate photometric redshift (photo- z) estimation with well-constrained uncertainties as inputs for weak lensing models to measure cosmological parameters. Machine learning methods have shown promise in optimizing the information gained from galaxy images in photo- z estimation; however, many of these methods are limited in their ability to estimate accurate uncertainties. In this work, we present one of the first applications of Bayesian convolutional neural networks (BCNNs) for photo- z estimation and uncertainties. In addition, we use conformal mapping to calibrate the photo- z uncertainties to achieve good statistical coverage. We use the public GalaxiesML data set of ∼300k galaxies from the Hyper Suprime-Cam survey containing five-band photometric images and known spectroscopic redshifts from 0 < z < 4. We find that the performance is much improved when using images compared to photometry, with the BCNN achieving 0.098 rms error, a standard outlier rate of 3.9%, a 3 σ outlier rate of 4.5%, and a bias of 0.0007. The performance drops significantly beyond z > 1.5 due to the relative lack of training data beyond those redshifts. This investigation demonstrates the power of using images directly and we advocate that future photo- z analysis of large-scale surveys include galaxy images. [ABSTRACT FROM AUTHOR]

In the Emergent scenario, the Universe should evolve from a nonsingular state replacing the typical singularity of General Relativity, for any initial condition. For the scalar field model by Ellis and Maartens [Class. Quantum Grav. 21 (2003) 223] we show that only a set of measure zero of trajectories leads to emergence, either from a static state (an Einstein model), or from a de Sitter state. Assuming a scenario based on CDM interacting with a Dark Energy fluid, we show that in general flat and open models expand from a nonsingular unstable de Sitter state at high energies; for some closed models this state is a transition phase with a bounce, other closed models are cyclic. A subset of these models are qualitatively in agreement with the observable Universe, accelerating at high energies, going through a matter-dominated decelerated era, then accelerating toward a de Sitter phase. [ABSTRACT FROM AUTHOR]