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We present photometric redshifts (photo- z) for the deep wide fields of the Physics of the Accelerating Universe Survey (PAUS), covering an area of |$\sim$| 50 deg |$^{2}$|⁠ , for |$\sim$| 1.8 million objects up to |$i_{\rm {AB}}\lt 23$|⁠. The PAUS deep wide fields overlap with the W1 and W3 fields from CFHTLenS and the G09 field from KiDS/GAMA. Photo- z are estimated using the 40 narrow bands (NB) of PAUS and the broad-bands (BB) of CFHTLenS and KiDS. We compute the redshifts with the SED template-fitting code bcnz , with a modification in the calibration technique of the zero-point between the observed and the modelled fluxes, that removes any dependence on spectroscopic redshift samples. We enhance the redshift accuracy by introducing an additional photo- z estimate (⁠|$z_{\textrm {b}}$|⁠), obtained through the combination of the bcnz and the BB-only photo- z. Comparing with spectroscopic redshift estimates (⁠|$z_{\textrm {s}}$|⁠), we obtain a |$\sigma _{68} \simeq 0.020$| for all galaxies with |$i_{\rm {AB}}\lt 23$| and a typical bias |$|z_{\textrm {b}}\!-\!z_{\textrm {s}}|$| smaller than 0.01. For |$z_{\textrm {b}} \sim (0.10\!-\!0.75)$|⁠ , we find |$\sigma _{68} \simeq (0.003\!-\!0.02)$|⁠ , this is a factor of |$10\!-\!2$| higher accuracy than the corresponding BB-only results. We obtain similar performance when we split the samples into red (passive) and blue (active) galaxies. We validate the redshift probability |$p(z)$| obtained by bcnz and compare its performance with that of |$z_{\textrm {b}}$|⁠. These photo- z catalogues will facilitate important science cases, such as the study of galaxy clustering and intrinsic alignment at high redshifts (⁠|$z \lesssim 1$|⁠) and faint magnitudes. [ABSTRACT FROM AUTHOR]

This study investigates the clustering and bias of Luminous Red Galaxies (LRG) in the BOSS-LOWZ, -CMASS, -COMB, and eBOSS samples, using two types of simulated lightcones: (i) high-fidelity lightcones from Uchuu N -body simulation, employing SHAM technique to assign LRG to (sub)haloes, and (ii) 16 000 covariance lightcones from GLAM-Uchuu N -body simulations, including LRG using HOD data from Uchuu. Our results indicate that Uchuu and glam lightcones closely replicate BOSS/eBOSS data, reproducing correlation function and power spectrum across scales from redshifts 0.2 to 1.0, from 2 to |$150 \,h^{-1}\,\mathrm{Mpc}$| in configuration space, from 0.005 to |$0.7\, h\,\mathrm{Mpc}^{-1}$| in Fourier space, and across different LRG stellar masses. Furthermore, comparing with existing MD-Patchy and EZmock BOSS/eBOSS lightcones based on approximate methods, our GLAM-Uchuu lightcones provide more precise clustering estimates. We identify significant deviations from observations within |$20 \,h^{-1}\,\mathrm{Mpc}$| scales in MD-Patchy and EZmock , with our covariance matrices indicating that these methods underestimate errors by between 10 per cent and 60 per cent. Lastly, we explore the impact of cosmology on galaxy clustering. Our findings suggest that, given the current level of uncertainties in BOSS/eBOSS data, distinguishing models with and without massive neutrino effects on large-scale structure (LSS) is challenging. This paper highlights the Uchuu and GLAM-Uchuu simulations' robustness in verifying the accuracy of Planck cosmological parameters, providing a strong foundation for enhancing lightcone construction in future LSS surveys. We also demonstrate that generating thousands of galaxy lightcones is feasible using N -body simulations with adequate mass and force resolution. [ABSTRACT FROM AUTHOR]

The physics of the accelerating Universe (PAU) camera is an optical narrow band and broad band imaging instrument mounted at the prime focus of the William Herschel Telescope. We describe the image calibration procedure of the PAU survey data. We rely on an external photometric catalogue to calibrate our narrow band data using stars that have been observed by both data sets. We fit stellar templates to the stellar broad-band photometry of the Sloan Digital Sky Survey and synthesize narrow band photometry that we compare to the PAUS narrow band data to determine their calibration. Consequently, the PAUS data are in the AB system as inherited from its reference calibrator. We do several tests to check the performance of the calibration. We find it self-consistent when comparing repeated observations of the same objects, with a good overall accuracy to the AB system which we estimate to be at the 2 per cent precision level and no significant trends as a function of narrow band filter or wavelength. Repeated observations allow us to build a spatial map of the illumination pattern of the system. We also check the wavelength dependence of the calibration comparing to stellar spectra. We find that using only blue stars reduces the effects of variations in the stellar template fitting to broad-band colours, improving the overall precision of the calibration to around 1 per cent and its wavelength uniformity. The photometric redshift performance obtained with the PAUS data attests to the validity of our calibration to reach the PAUS science goals. [ABSTRACT FROM AUTHOR]

The spectroscopic survey of the China's Space Survey Telescope (CSST) is expected to obtain a huge number of slitless spectra, including more than one hundred million galaxy spectra and millions of active galactic nuclei (AGNs) spectra. By making use of these spectra, we can measure the Baryon Acoustic Oscillation (BAO) signals over large redshift ranges with excellent precisions. In this work, we predict the CSST measurements of the post-reconstruction galaxy power spectra at |$0\lt z\lt 1.2$| and pre-reconstruction AGN power spectra at |$0\lt z\lt 4$|⁠ , and derive the BAO signals at different redshift bins by constraining the BAO scaling parameters using the Markov Chain Monte Carlo method. Our result shows that the CSST spectroscopic survey can provide accurate BAO measurements with precisions higher than 1 and 3 per cent for the galaxy and AGN surveys, respectively. By comparing with current measurements in the same range at low redshifts, this can improve the precisions by a factor of |$2\sim 3$|⁠ , and similar precisions can be obtained in the pessimistic case. We also investigate the constraints on the cosmological parameters using the measured BAO data by the CSST , and obtain stringent constraint results for the energy density of dark matter, Hubble constant, and equation of state of dark energy. [ABSTRACT FROM AUTHOR]

We use the spherical collapse model to demonstrate that the observable average density of virialized clusters depends on the properties of dark energy along with the properties of gravity on cluster scales and can therefore be used as a probe of these properties. As an application of this approach, we derive the predicted virialized densities and radii of cluster mass structures for a wide range of values of the cosmological constant (including negative values) as a function of the turnaround redshift. For the value of ΩΛ,0 = −0.7 (with Ω m ,0 = 0.3), we find an amplification of the density of virialized clusters which can be as large as 80 per cent compared to Planck18/lambda Cold Dark Matter (ΛCDM) for a turnaround redshift z max ≳ 2. Such an amplification may lead to more efficient early galaxy formation in this class of models, in accordance with the recent findings of JWST , which may be partially pertinent to the Λ sign switching models (ΛsCDM), which have been suggested as potential solutions to the observed Hubble and S 8 discrepancies. [ABSTRACT FROM AUTHOR]

Gravitational waves (GWs) provide a new avenue to test Einstein's General Relativity (GR) using the ongoing and upcoming GW detectors by measuring the redshift evolution of the effective Planck mass proposed by several modified theories of gravity. We propose a model-independent, data-driven approach to measure any deviation from GR in the GW propagation effect by combining multimessenger observations of GW sources accompanied by EM counterparts, commonly known as bright sirens [Binary Neutron Star (BNS) and Neutron Star Black Hole systems (NSBH)]. We show that by combining the GW luminosity distance measurements from bright sirens with the Baryon Acoustic Oscillation (BAO) measurements derived from galaxy clustering, and the sound horizon measurements from the Cosmic Microwave Background (CMB), we can make a data-driven reconstruction of deviation of the variation of the effective Planck mass (jointly with the Hubble constant) as a function of cosmic redshift. Using this technique, we achieve a precise measurement of GR with redshift (z) with a precision of approximately 7.9 per cent for BNSs at redshift z = 0.075 and 10 per cent for NSBHs at redshift z = 0.225 with 5 yr of observation from LIGO-Virgo-KAGRA network of detectors. Employing Cosmic Explorer and Einstein Telescope for just 1 yr yields the best precision of about 1.62 per cent for BNSs and 2 per cent for NSBHs at redshift z = 0.5 on the evolution of the frictional term, and a similar precision up to z = 1. This measurement can discover potential deviation from any kind of model that impacts GW propagation with ongoing and upcoming observations. [ABSTRACT FROM AUTHOR]

This work explores the relationships between galaxy sizes and related observable galaxy properties in a large volume cosmological hydrodynamical simulation. The objectives of this work are to develop a better understanding of both the correlations between galaxy properties and the influence of environment on galaxy physics in order to build an improved model for the galaxy sizes, building off of the fundamental plane. With an accurate intrinsic galaxy size predictor, the residuals in the observed galaxy sizes can potentially be used for multiple cosmological applications, including making measurements of galaxy velocities in spectroscopic samples, estimating the rate of cosmic expansion, and constraining the uncertainties in the photometric redshifts of galaxies. Using projection pursuit regression, the model accurately predicts intrinsic galaxy sizes and have residuals which have limited correlation with galaxy properties. The model decreases the spatial correlation of galaxy size residuals by a factor of ∼5 at small scales compared to the baseline correlation when the mean size is used as a predictor. [ABSTRACT FROM AUTHOR]

We present an investigation into a hitherto unexplored systematic that affects the accuracy of galaxy cluster mass estimates with weak gravitational lensing. Specifically, we study the covariance between the weak lensing signal, ΔΣ, and the 'true' cluster galaxy number count, N gal, as measured within a spherical volume that is void of projection effects. By quantifying the impact of this covariance on mass calibration, this work reveals a significant source of systematic uncertainty. Using the MDPL2 simulation with galaxies traced by the SAGE semi-analytic model, we measure the intrinsic property covariance between these observables within the three-dimensional vicinity of the cluster, spanning a range of dynamical mass and redshift values relevant for optical cluster surveys. Our results reveal a negative covariance at small radial scales (R ≲ R 200c) and a null covariance at large scales (R ≳ R 200c) across most mass and redshift bins. We also find that this covariance results in a |$2{\!-\!}3~{{\ \rm per\ cent}}$| bias in the halo mass estimates in most bins. Furthermore, by modelling N gal and ΔΣ as multi-(log)-linear equations of secondary halo properties, we provide a quantitative explanation for the physical origin of the negative covariance at small scales. Specifically, we demonstrate that the N gal–ΔΣ covariance can be explained by the secondary properties of haloes that probe their formation history. We attribute the difference between our results and the positive bias seen in other works with (mock)-cluster finders to projection effects. These findings highlight the importance of accounting for the covariance between observables in cluster mass estimation, which is crucial for obtaining accurate constraints on cosmological parameters. [ABSTRACT FROM AUTHOR]

We use a galaxy sample derived from the Dark Energy Camera Legacy Survey Data Release 9 to measure the baryonic acoustic oscillations (BAO). The magnitude-limited sample consists of 10.6 million galaxies in an area of 4974 deg2 over the redshift range of [0.6, 1]. A key novelty of this work is that the true redshift distribution of the photo- z sample is derived from the self-calibration method, which determines the true redshift distribution using the clustering information of the photometric data alone. Through the angular correlation function in four tomographic bins, we constrain the BAO scale dilation parameter α to be 1.025 ± 0.033, consistent with the fiducial Planck cosmology. Alternatively, the ratio between the comoving angular diameter distance and the sound horizon, D M/ r s, is constrained to be 18.94 ± 0.61 at the effective redshift of 0.749. We corroborate our results with the true redshift distribution obtained from a weighted spectroscopic sample, finding very good agreement. We have conducted a series of tests to demonstrate the robustness of the measurement. Our work demonstrates that the self-calibration method can effectively constrain the true redshift distribution in cosmological applications, especially in the context of photometric BAO measurement. [ABSTRACT FROM AUTHOR]

Constraints on the potential properties of superconducting cosmic strings provide an indirect probe of physics beyond the standard model at energies inaccessible to terrestrial particle colliders. In this study, we perform the first joint Bayesian analysis to extract constraints on superconducting cosmic strings from current 21-cm signal measurements while accounting rigorously for the uncertainties in foregrounds and high redshift astrophysics. We include the latest publicly available 21-cm power spectrum upper limits from HERA, 21-cm global signal data from SARAS 3, and the synergistic probe of the unresolved X-ray background in our final analysis. This paper thus constitutes the first attempt to use 21-cm power spectrum data to probe cosmic strings. In contrast to previous works, we find no strong constraints can be placed on superconducting cosmic strings from current 21-cm measurements. This is because of uncertainties in the X-ray emission efficiency of the first galaxies, with X-ray emissivities greater than 3 × 1040 erg s−1 M |$_{\odot }^{-1}$|  yr able to mask the presence of cosmic strings in the 21-cm signal. We conclude by discussing the prospects for future constraints from definitive 21-cm signal measurements and argue that the recently proposed soft photon heating should be cause for optimism due to its potential to break degeneracies that would have otherwise made the signatures of cosmic strings difficult to distinguish from those of astrophysical origin. [ABSTRACT FROM AUTHOR]

We describe JWST /NIRSpec prism measurements of Ly α emission in z ≳ 5 galaxies. We identify Ly α detections in 10 out of 69 galaxies with robust rest-optical emission-line redshift measurements at 5 ≤ z < 7 in the Cosmic Evolution Early Release Science (CEERS) and DDT-2750 observations of the Extended Groth Strip field. Galaxies at z ≃ 6 with faint continuum (F 150 W =27–29 mag) are found with extremely large rest-frame Ly α equivalent widths (EWs; ranging up to 286 Å). Likely Ly α detections are also seen in two new z > 7 galaxies (z  = 7.49 and 7.17) from the second epoch of CEERS observations, both showing large Ly α EWs that likely indicate significant transmission through the intergalactic medium (IGM). We measure high Ly α escape fractions in the 12 Ly α emitters in our sample (median 0.28), two of which show |$f_{\rm esc}^{ {\rm Ly}\alpha }$| near unity (>0.80). We find that |$50_{-11}^{+11}$|  per cent of z ≃ 6 galaxies with [O  iii ] + H β EW>1000 Å have |$f_{\rm esc}^{ {\rm Ly}\alpha }$| >0.2, consistent with the fractions found in lower redshift samples with matched [O  iii ] + H β EWs. While uncertainties are still significant, we find that only |$10_{-5}^{+9}$|  per cent of z > 7 galaxies with similarly strong rest optical emission lines show such large |$f_{\rm esc}^{ {\rm Ly}\alpha }$|⁠ , as may be expected if IGM attenuation of Ly α increases towards higher redshifts. We identify photometric galaxy overdensities near the z ≳ 7 Ly α emitters, potentially providing the ionizing flux necessary to create large ionized sightlines that facilitate Ly α transmission. Finally, we investigate the absence of Ly α emission in a comparable (and spectroscopically confirmed) galaxy overdensity at z  = 7.88 in the Abell 2744 field, discussing new prism spectra of the field obtained with the UNCOVER program. [ABSTRACT FROM AUTHOR]

The current and next observation seasons will detect hundreds of gravitational waves (GWs) from compact binary systems coalescence at cosmological distances. When combined with independent electromagnetic measurements, the source redshift will be known, and we will be able to obtain precise measurements of the Hubble constant H 0 via the distance–redshift relation. However, most observed mergers are not expected to have electromagnetic counterparts, which prevents a direct redshift measurement. In this scenario, one possibility is to use the dark sirens method that statistically marginalizes over all the potential host galaxies within the GW location volume to provide a probabilistic source redshift. Here we presented H 0 measurements using two new dark sirens compared to previous analyses using DECam data: GW190924 |$\_$| 021846 and GW200202 |$\_$| 154313. The photometric redshifts of the possible host galaxies of these two events are acquired from the DECam Local Volume Exploration Survey (DELVE) carried out on the Blanco telescope at Cerro Tololo. The combination of the H 0 posterior from GW190924 |$\_$| 021846 and GW200202 |$\_$| 154313 together with the bright siren GW170817 leads to |$H_{0} = 68.84^{+15.51}_{-7.74}\, \rm {km\, s^{-1}\, Mpc^{-1}}$|⁠. Including these two dark sirens improves the 68  per cent confidence interval (CI) by 7  per cent over GW170817 alone. This demonstrates that the addition of well-localized dark sirens in such analysis improves the precision of cosmological measurements. Using a sample containing 10 well-localized dark sirens observed during the third LIGO/Virgo observation run, without the inclusion of GW170817, we determine a measurement of |$H_{0} = 76.00^{+17.64}_{-13.45}\, \rm {km\, s^{-1}\, Mpc^{-1}}$|⁠. [ABSTRACT FROM AUTHOR]

We present a novel approach for measuring the two-point correlation function of galaxies in narrow pencil beam surveys with varying depths. Our methodology is utilized to expand high-redshift galaxy clustering investigations up to z ∼ 8 by analysing a comprehensive sample consisting of N g = 160 Lyman break galaxy candidates obtained through optical and near-infrared photometric data within the CANDELS GOODS data sets from the Hubble Space Telescope Legacy Fields. For bright sources with M UV < −19.8, we determine a galaxy bias of b  = 9.33 ± 4.90 at |$\overline{z} = 7.7$| and a correlation length of r 0 = 10.74 ± 7.06  |$h^{-1}\, \mathrm{Mpc}$|⁠. We obtain similar results for the XDF, with a galaxy bias measurement of b  = 8.26 ± 3.41 at the same redshift for a slightly fainter sample with a median luminosity of M UV = −18.4. By comparing with dark-matter halo bias and employing abundance matching, we deduce a characteristic halo mass of Mh ∼ 1011.5 M⊙ and a duty cycle close to unity. To validate our approach for variable-depth data sets, we replicate the analysis in a region with near-uniform depth using a standard two-point correlation function estimator, yielding consistent outcomes. Our study not only provides a valuable tool for future utilization in JWST data sets but also suggests that the clustering of early galaxies continues to increase with redshift beyond z ≳ 8, potentially contributing to the existence of protocluster structures observed in early JWST imaging and spectroscopic surveys at z ≳ 8. [ABSTRACT FROM AUTHOR]

We present a study of C  i /H2 relative abundance in the diffuse cold neutral medium (CNM). Using the chemical and thermal balance model, we calculate the dependence of C  i /H2 on the main parameters of the medium: hydrogen number density, metallicity, strength of the UV field, and cosmic ray ionization rate (CRIR). We show that the observed relative C  i and H2 column densities in damped Lyman alpha systems (DLAs) at high redshifts can be reproduced within our model assuming the typically expected conditions in the diffuse CNM. Using additional observed information on metallicity, H  i column density, and excitation of C  i fine-structure levels, as well as temperature, we estimated for a wide range metallicities in the CNM at high redshifts that CRIRs are in the range from ∼10−16 to a |$\rm few \times 10^{-15}\, \rm s^{-1}$|⁠ , hydrogen number densities are in the range ∼10−103 cm−3, and the UV field is in the range from 10−2 to a |$\rm few \times 10^2$| of the Mathis field. We argue that because the observed quantities used in this work are quite homogeneous and much less affected by radiative transfer effects (in comparison with, for example, the dissociation of HD and UV pumping of H2 rotational levels), our estimates are quite robust against the assumption of the exact geometrical model of the cloud and local sources of the UV field. [ABSTRACT FROM AUTHOR]

The possibility of watching the Universe expand in real time and in a model-independent way, first envisaged by Allan Sandage more than 60 yr ago and known as the redshift drift, is within reach of forthcoming astrophysical facilities, particularly the Extremely Large Telescope (ELT) and the Square Kilometre Array Observatory (SKAO). The latter, probing lower redshifts, enables us to watch the Universe's acceleration era in real time, while the former does the same for the matter era. We use Fisher matrix analysis techniques, which we show to give comparable results to those of a Markov Chain Monte Carlo approach, to discuss forecasts for SKAO measurements of the redshift drift and their cosmological impact. We consider specific fiducial cosmological models but mainly rely on a more agnostic cosmographic series (which includes the deceleration and jerk parameters), and we also discuss prospects for measurements of the drift of the drift. Overall, our analysis shows that SKAO measurements, with a reasonable amount of observing time, can provide a competitive probe of the low-redshift accelerating Universe. [ABSTRACT FROM AUTHOR]

Modified theories of gravity encompass a class of f (R) models that seek to elucidate the observed late-time accelerated expansion of the universe. In this study, we examine a set of viable f (R) models (Hu–Sawicki: two cases, Satrobinsky, Tsujikawa, exponential and arcTanh models) in metric formalism, using recent cosmological data sets: type Ia supernovae data, cosmic chronometer observations, baryonic acoustic oscillations data, data from H  ii starburst galaxies, local measurements of the Hubble parameter (H 0), and cosmic microwave background radiation data. We re-parametrize the f (R) models using a distortion/deviation parameter (b) which is a measure of their deviation from the lambda-cold dark matter (ΛCDM) model. Taking into account the 'Hubble tension,' we perform the study both with and without a Gaussian prior for H 0 from local measurements, following the standard statistical procedures for constraining parameters and comparing models. Our findings are as follows: (i) in many cases the f (R) models are strongly favoured over the standard ΛCDM model, (ii) the deviation parameter (b) significantly deviates from zero in several cases, (iii) the inclusion of local H 0 not only increases the fitted value of H 0 (as expected) but also affects the gap between predictions of f (R) models and the ΛCDM model, and (iv) the relevant quantities characterizing the (accelerated) expansion of the universe such as transition redshift and the equations-of-state parameters, obtained in our models, are consistent with those obtained in a model-independent way by others. Our investigation and results present a compelling case for pursuing further research on f (R) models with future observations to come. [ABSTRACT FROM AUTHOR]

We perform the weak lensing mass mapping analysis to identify troughs , which are defined as local minima in the mass map. Since weak lensing probes the projected matter distribution along the line of sight, these troughs can be produced by single or multiple voids projected along the line of sight. To scrutinize the origins of the weak lensing troughs, we systematically investigate the line-of-sight structure of troughs selected from the latest Subaru Hyper Suprime-Cam (HSC) Year 3 weak lensing data covering |$433.48 \, \mathrm{deg}^2$|⁠. From a curved sky mass map constructed with the HSC data, we identify 15 troughs with the signal-to-noise ratio higher than 5.7 and address their line-of-sight density structure utilizing redshift distributions of two galaxy samples, photometric luminous red galaxies observed by HSC and spectroscopic galaxies detected by Baryon Oscillation Spectroscopic Survey. While most weak lensing signals due to the troughs are explained by multiple voids aligned along the line of sight, we find that two of the 15 troughs potentially originate from single voids at redshift ∼0.3. The single void interpretation appears to be consistent with our three-dimensional mass mapping analysis. We argue that single voids can indeed reproduce observed weak lensing signals at the troughs if these voids are not spherical but are highly elongated along the line-of-sight direction. [ABSTRACT FROM AUTHOR]

An accurate reconstruction of galaxy cluster masses is key to use this population of objects as a cosmological probe. In this work we present a study on the hydrostatic-to-lensing mass scaling relation for a sample of 53 clusters whose masses were reconstructed homogeneously in a redshift range between z = 0.05 and 1.07. The M500 mass for each cluster was indeed inferred from the mass profiles extracted from the X-ray and lensing data, without using a priori observable-mass scaling relations. We assessed the systematic dispersion of the masses estimated with our reference analyses with respect to other published mass estimates. Accounting for this systematic scatter does not change our main results, but enables the propagation of the uncertainties related to the mass reconstruction method or used dataset. Our analysis gives a hydrostatic-to-lensing mass bias of (1−b) = 0.739−0.070+0.075 and no evidence of evolution with redshift. These results are robust against possible subsample differences. [ABSTRACT FROM AUTHOR]

We present ICAROGW 2.0, a pure python code developed to infer the astrophysical and cosmological population properties of noisy, heterogeneous, and incomplete observations. The code has mainly been developed for compact binary coalescence (CBC) population inference with gravitational wave (GW) observations. It contains several models for the masses, spins, and redshift of CBC distributions and it is able to infer population distributions, as well as the cosmological parameters and possible general relativity deviations at cosmological scales. Here, we present the theoretical and computational foundations of ICAROGW 2.0 and describe how the code can be employed for population and cosmological inference using (i) only GWs, (ii) GWs and galaxy surveys, and (iii) GWs with electromagnetic counterparts. We discuss the code performance on GPUs, finding a gain in computation time of about two orders of magnitude when more than 100 GW events are involved in the analysis. We have validated the code by re-analyzing GW population and cosmological studies, finding very good agreement with previous results. [ABSTRACT FROM AUTHOR]

Direct detection of the Cosmic Dawn and Epoch of Reionization via the redshifted 21-cm line of neutral Hydrogen will have unprecedented implications for studying structure formation in the early Universe. This exciting goal is challenged by the difficulty of extracting the faint 21-cm signal buried beneath bright astrophysical foregrounds and contaminated by numerous systematics. Here, we focus on improving the Gaussian Process Regression (GPR) signal separation method originally developed for LOFAR observations. We address a key limitation of the current approach by incorporating covariance prior models learnt from 21-cm signal simulations using variational autoencoder (VAE) and interpolatory autoencoder (IAE). Extensive tests are conducted to evaluate GPR, VAE–GPR, and IAE–GPR in different scenarios. Our findings reveal that the new method outperforms standard GPR in component separation tasks. Moreover, the improved method demonstrates robustness when applied to signals not represented in the training set. It also presents a certain degree of resilience to data systematics, highlighting its ability to effectively mitigate their impact on the signal recovery process. However, our findings also underscore the importance of accurately characterizing and understanding these systematics to achieve successful detection. Our generative approaches provide good results even with limited training data, offering a valuable advantage when a large training set is not feasible. Comparing the two algorithms, IAE–GPR shows slightly higher fidelity in recovering power spectra compared to VAE–GPR. These advancements highlight the strength of generative approaches and optimize the analysis techniques for future 21-cm signal detection at high redshifts. [ABSTRACT FROM AUTHOR]

The shear measurement from the Dark Energy Camera Legacy Survey (DECaLS) provides an excellent opportunity for galaxy–galaxy lensing study with the Dark Energy Spectroscopic Instrument (DESI) galaxies, given the large (∼9000 deg2) sky overlap. We explore this potential by combining the DESI 1 per cent survey and DECaLS Data Release 8 (DR8). With ∼106 deg2 sky overlap, we achieve significant detection of galaxy–galaxy lensing for Bright Galaxy Survey (BGS) and luminous red galaxy (LRG) as lenses. Scaled to the full BGS sample, we expect the statistical errors to improve from |$18(12)\,{\rm per \ cent}$| to a promising level of |$2(1.3)\,{\rm per \ cent}$| at |$\theta \gt 8\,\mathrm{ arcmin} \, (\lt 8\,\mathrm{ arcmin})$|⁠. This brings stronger requirements for future systematics control. To fully realize such potential, we need to control the residual multiplicative shear bias | m | < 0.006 and the bias in the mean redshift |Δ z | < 0.008, requiring the introduced bias in the measurement is <0.31σ. We also expect significant detection of galaxy–galaxy lensing with DESI LRG/emission line galaxy (ELG) full samples as lenses, and cosmic magnification of ELG through cross-correlation with low-redshift DECaLS shear. If such systematical error control can be achieved, we find the advantages of DECaLS, comparing with the Kilo Degree Survey (KiDS) and the Hyper Suprime-Cam (HSC), are at low redshift, large scale, and in measuring the shear ratio (to σ R ∼ 0.04) and cosmic magnification. [ABSTRACT FROM AUTHOR]

We present posterior sample redshift distributions for the Hyper Suprime-Cam Subaru Strategic Program Weak Lensing three-year (HSC Y3) analysis. Using the galaxies' photometry and spatial cross-correlations, we conduct a combined Bayesian Hierarchical Inference of the sample redshift distributions. The spatial cross-correlations are derived using a subsample of Luminous Red Galaxies (LRGs) with accurate redshift information available up to a photometric redshift of z < 1.2. We derive the photometry-based constraints using a combination of two empirical techniques calibrated on spectroscopic and multiband photometric data that cover a spatial subset of the shear catalogue. The limited spatial coverage induces a cosmic variance error budget that we include in the inference. Our cross-correlation analysis models the photometric redshift error of the LRGs to correct for systematic biases and statistical uncertainties. We demonstrate consistency between the sample redshift distributions derived using the spatial cross-correlations, the photometry, and the posterior of the combined analysis. Based on this assessment, we recommend conservative priors for sample redshift distributions of tomographic bins used in the three-year cosmological Weak Lensing analyses. [ABSTRACT FROM AUTHOR]

We present direct constraints on galaxy intrinsic alignments (IAs) using the Dark Energy Survey Year 3 (DES Y3), the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), and its precursor, the Baryon Oscillation Spectroscopic Survey (BOSS). Our measurements incorporate photometric red sequence (redMaGiC) galaxies from DES with median redshift z ∼ 0.2–1.0, luminous red galaxies from eBOSS at z ∼ 0.8, and also an SDSS-III BOSS CMASS sample at z ∼ 0.5. We measure two-point IA correlations, which we fit using a model that includes lensing, magnification, and photometric redshift error. Fitting on scales 6 Mpc  h −1 < r p < 70 Mpc  h −1, we make a detection of IAs in each sample, at 5σ–22σ (assuming a simple one-parameter model for IAs). Using these red samples, we measure the IA–luminosity relation. Our results are statistically consistent with previous results, but offer a significant improvement in constraining power, particularly at low luminosity. With this improved precision, we see detectable dependence on colour between broadly defined red samples. It is likely that a more sophisticated approach than a binary red/blue split, which jointly considers colour and luminosity dependence in the IA signal, will be needed in future. We also compare the various signal components at the best-fitting point in parameter space for each sample, and find that magnification and lensing contribute |$\sim 2\!-\!18~{{\ \rm per\ cent}}$| of the total signal. As precision continues to improve, it will certainly be necessary to account for these effects in future direct IA measurements. Finally, we make equivalent measurements on a sample of emission-line galaxies from eBOSS at z ∼ 0.8. We constrain the non-linear alignment amplitude to be |$A_1=0.07^{+0.32}_{-0.42}$| (| A 1| < 0.78 at 95 per cent CL). [ABSTRACT FROM AUTHOR]

We have measured the angular autocorrelation function of near-infrared galaxies in SERVS + DeepDrill, the Spitzer Extragalactic Representative Volume Survey and its follow-up survey of the Deep Drilling Fields, in three large fields totalling over 20 deg2 on the sky, observed in two bands centred on 3.6 and 4.5 μ m. We performed this analysis on the full sample as well as on sources selected by [3.6]–[4.5] colour in order to probe clustering for different redshift regimes. We estimated the spatial correlation strength as well, using the redshift distribution from S-COSMOS with the same source selection. The strongest clustering was found for our bluest subsample, with 〈 z 〉 ∼ 0.7, which has the narrowest redshift distribution of all our subsamples. We compare these estimates to previous results from the literature, but also to estimates derived from mock samples, selected in the same way as the observational data, using deep light-cones generated from the SHARK semi-analytical model of galaxy formation. For all simulated (sub)samples, we find a slightly steeper slope than for the corresponding observed ones, but the spatial clustering length is comparable in most cases. [ABSTRACT FROM AUTHOR]

We present the splashback radius measurements around the SRG/eROSITA eFEDS X-ray selected galaxy clusters by cross-correlating them with HSC S19A photometric galaxies. The X-ray selection is expected to be less affected by systematics related to projection that affects optical cluster finder algorithms. We use a nearly volume-limited sample of 109 galaxy clusters selected in 0.5–2.0 keV band having luminosity |$L_X \gt 10^{43.5}\, {\rm erg \, s}^{-1}\, h^{-2}$| within the redshift z < 0.75 and obtain measurements of the projected cross-correlation with a signal to noise of 17.43. We model our measurements to infer a 3D profile and find that the steepest slope is sharper than −3 and associate the location with the splashback radius. We infer the value of the 3D splashback radius |$r_{\rm sp} = 1.45^{+0.30}_{-0.26}\, h^{-1}\, {\rm Mpc}$|. We also measure the weak-lensing signal of the galaxy clusters and obtain halo mass |$\log [M_{\rm 200m}/ h^{-1}\, {\rm M_\odot }] = 14.52 \pm 0.06$| using the HSC-S16A shape catalogue data at the median redshift z  = 0.46 of our cluster sample. We compare our r sp values with the spherical overdensity boundary |$r_{\rm 200m} = 1.75 \pm 0.08\, h^{-1} \, {\rm Mpc}$| based on the halo mass, which is consistent within 1.2σ with the ΛCDM predictions. Our constraints on the splashback radius, although broad, are the best measurements thus far obtained for an X-ray selected galaxy cluster sample. [ABSTRACT FROM AUTHOR]

We present the strong lensing analysis of two galaxy clusters: MACS J0242.5-2132 (MACS J0242, z  = 0.313) and MACS J0949.8+1708 (MACS J0949, z  = 0.383). Their total matter distributions are constrained, thanks to the powerful combination of observations with the Hubble Space Telescope (HST) and the Multi-Unit Spectroscopic Explorer instrument. Using these observations, we precisely measure the redshift of six multiple image systems in MACS J0242 and two in MACS J0949. We also include four multiple image systems in the latter cluster identified in HST imaging without MUSE redshift measurements. For each cluster, our best-fit mass model consists of a single cluster-scale halo and 57 (170) galaxy-scale halos for MACS J0242 (MACS J0949). Multiple images positions are predicted with a rms 0.39 arcsec and 0.15 arcsec for MACS J0242 and MACS J0949 models, respectively. From these mass models, we derive aperture masses of M (R <200 kpc |$) = 1.67_{-0.05}^{+0.03}\times 10^{14}\, {\rm M}_{\odot }$| and M (R <200 kpc |$) = 2.00_{-0.20}^{+0.05}\times 10^{14}\, {\rm M}_{\odot }$|⁠. Combining our analysis with X-ray observations from the XMM−Newton Observatory , we show that MACS J0242 appears to be a relatively relaxed cluster, whereas conversely, MACS J0949 shows a relaxing post-merger state. At 200 kpc, X-ray observations suggest the hot gas fraction to be, respectively, |$f_g = 0.115^{+0.003}_{-0.004}$| and |$0.053^{+0.007}_{-0.006}$| for MACS J0242 and MACS J0949. MACS J0242 being relaxed, its density profile is very well fitted by a Navarro−Frenk−White distribution, in agreement with X-ray observations. Finally, the strong lensing analysis of MACS J0949 suggests a flat dark matter density distribution in the core, between 10 and 100 kpc. This appears consistent with X-ray observations. [ABSTRACT FROM AUTHOR]

The recent |$\sim 4 \, \sigma$| Hubble constant, H 0, tension is observed between the value of H 0 from the cosmic microwave background (CMB) and Type Ia supernovae (SNe Ia). It is a decade since this tension is excruciating the modern astrophysical community. To shed light on this problem is key to consider probes at intermediate redshifts between SNe Ia and CMB and reduce the uncertainty on H 0. Toward these goals, we fill the redshift gap by employing gamma-ray bursts (GRBs) and quasars (QSOs), reaching z  = 9.4 and z  = 7.6, respectively, combined with baryonic acoustic oscillations (BAO), and SNe Ia. To this end, we employ the 'Dainotti GRB 3D relation' among the rest-frame end time of the X-ray plateau emission, its corresponding luminosity, and the peak prompt luminosity, and the 'Risaliti–Lusso' QSO relation between ultraviolet and X-ray luminosities. We inquire the commonly adopted Gaussianity assumption on GRBs, QSOs, and BAO. With the joint sample, we fit the flat Λ Cold Dark Matter model with both the Gaussian and the newly discovered likelihoods. We also investigate the impact of the calibration assumed for Pantheon and Pantheon  + SNe Ia on this analysis. Remarkably, we show that only GRBs fulfil the Gaussianity assumption. We achieve small uncertainties on the matter-density parameter Ω M and H 0. We find H 0 values compatible within 2σ with the one from the Tip of the Red Giant Branch. Finally, we show that the cosmological results are heavily biased against the arbitrary calibration choice for SNe Ia. [ABSTRACT FROM AUTHOR]

The relationship linking a galaxy cluster's total mass with the concentration of its mass profile and its redshift is a fundamental prediction of the Cold Dark Matter (CDM) paradigm of cosmic structure formation. However, confronting those predictions with observations is complicated by the fact that simulated clusters are not representative of observed samples where detailed mass profile constraints are possible. In this work, we calculate the symmetry-peakiness-alignment (SPA) morphology metrics for maps of X-ray emissivity from the three hundred project hydrodynamical simulations of galaxy clusters at four redshifts, and thereby select a sample of morphologically relaxed, simulated clusters, using observational criteria. These clusters have on average earlier formation times than the full sample, confirming that they are both morphologically and dynamically more relaxed than typical. We constrain the concentration–mass–redshift relation of both the relaxed and complete sample of simulated clusters, assuming power-law dependences on mass (κm) and 1 + z (κζ), finding κm = −0.12 ± 0.07 and κζ = −0.27 ± 0.19 for the relaxed subsample. From an equivalently selected sample of massive, relaxed clusters observed with Chandra , we find κm = −0.12 ± 0.08 and κζ = −0.48 ± 0.19, in good agreement with the simulation predictions. The simulated and observed samples also agree well on the average concentration at a pivot mass and redshift providing further validation of the ΛCDM paradigm in the properties of the largest gravitationally collapsed structures observed. This also represents the first clear detection of decreasing concentration with redshift, a longstanding prediction of simulations in data. [ABSTRACT FROM AUTHOR]

In a previous paper, we demonstrated a single-rung method for measuring cosmological distances in active galactic nuclei (AGNs) that can be used from low redshift (z < 0.1) to high redshift (z > 3). This method relies on the assumption that the variability seen in AGNs is constrained by the speed of light during a flare event and can therefore be used to estimate the size of an emitting region. A limitation of this method is that previously, the Doppler factor was required to be known. In this paper, we derive an extension of the 'standard speed-gun' method for measuring cosmological distances that depends on the maximum intrinsic brightness temperature that a source can reach, rather than the Doppler factor. If the precise value of the intrinsic brightness temperature does not evolve with redshift, and flares are statistically independent, we can in principle improve the errors on measurements of the matter content of the Universe (in a flat Lambda cold dark matter model) statistically. We then explored how well a future observing programme would constrain cosmological parameters. We found that recovering the input cosmology depends critically on the uncertainty of the intrinsic brightness temperature and the number of flares observed. [ABSTRACT FROM AUTHOR]

We investigate the dependence of Lyα emitter (LAE) clustering on Lyα luminosity and connect the clustering properties of ≈L⋆ LAEs with those of much fainter ones, namely, ≈0.04L⋆. We use 1030 LAEs from the MUSE-Wide survey, 679 LAEs from MUSE-Deep, and 367 LAEs from the to-date deepest ever spectroscopic survey, the MUSE Extremely Deep Field. All objects have spectroscopic redshifts of 3 < z < 6 and cover a large dynamic range of Lyα luminosities: 40.15 < log(LLyα/erg s−1) < 43.35. We apply the Adelberger et al. K-estimator as the clustering statistic and fit the measurements with state-of-the-art halo occupation distribution (HOD) models. We find that the large-scale bias factor increases weakly with an increasing line luminosity. For the low-luminosity (log⟨LLyα/[erg s−1]⟩ = 41.22) and intermediate-luminosity (log⟨LLyα/[erg s−1]⟩ = 41.64) LAEs, we compute consistent bias factors blow = 2.43−0.15+0.15 b low = 2. 43 − 0.15 + 0.15 $ b_\mathrm{{low}}=2.43^{+0.15}_{-0.15} $ and binterm. = 2.42−0.09+0.10 b interm. = 2. 42 − 0.09 + 0.10 $ b_\mathrm{{interm.}}=2.42^{+0.10}_{-0.09} $ , whereas for the high-luminosity (log⟨LLyα/[erg s−1]⟩ = 42.34) LAEs we calculated bhigh = 2.65−0.11+0.13 b high = 2. 65 − 0.11 + 0.13 $ b_\mathrm{{high}}=2.65^{+0.13}_{-0.11} $. Consequently, high-luminosity LAEs occupy dark matter halos (DMHs) with typical masses of log(Mh/[h−1 M⊙]) = 11.09−0.09+0.10 log (M h / [ h − 1 M ⊙ ]) = 11. 09 − 0.09 + 0.10 $ \log (M_{\mathrm{h}}/[h^{-1}M_\odot])=11.09^{+0.10}_{-0.09} $ , while low-luminosity LAEs reside in halos of log(Mh/[h−1 M⊙]) = 10.77−0.15+0.13 log (M h / [ h − 1 M ⊙ ]) = 10. 77 − 0.15 + 0.13 $ \log (M_{\mathrm{h}}/[h^{-1}M_\odot])=10.77^{+0.13}_{-0.15} $. The minimum masses to host one central LAE, Mmin, and (on average) one satellite LAE, M1, also vary with Lyα luminosity, growing from log(Mmin/[h−1M⊙]) = 10.3−0.3+0.2 log (M min / [ h − 1 M ⊙ ]) = 10. 3 − 0.3 + 0.2 $ \log (M_\mathrm{{min}}/[h^{-1}M_\odot])=10.3^{+0.2}_{-0.3} $ and log(M1/[h−1 M⊙]) = 11.7−0.2+0.3 log (M 1 / [ h − 1 M ⊙ ]) = 11. 7 − 0.2 + 0.3 $ \log (M_1/[h^{-1}M_\odot])=11.7^{+0.3}_{-0.2} $ to log(Mmin/[h−1 M⊙]) = 10.7−0.3+0.2 log (M min / [ h − 1 M ⊙ ]) = 10. 7 − 0.3 + 0.2 $ \log (M_\mathrm{{min}}/[h^{-1}M_\odot])=10.7^{+0.2}_{-0.3} $ and log(M1/[h−1 M⊙]) = 12.4−0.6+0.4 log (M 1 / [ h − 1 M ⊙ ]) = 12. 4 − 0.6 + 0.4 $ \log (M_1/[h^{-1}M_\odot])=12.4^{+0.4}_{-0.6} $ from low- to high-luminosity samples, respectively. The satellite fractions are ≲10% (≲20%) at 1σ (3σ) confidence level, supporting a scenario in which DMHs typically host one single LAE. We next bisected the three main samples into disjoint subsets to thoroughly explore the dependence of the clustering properties on LLyα. We report a strong (8σ) clustering dependence on Lyα luminosity, not accounting for cosmic variance effects, where the highest luminosity LAE subsample (log(LLyα/erg s−1) ≈ 42.53) clusters more strongly (bhighest = 3.13−0.15+0.08 b highest = 3. 13 − 0.15 + 0.08 $ b_\mathrm{{highest}}=3.13^{+0.08}_{-0.15} $) and resides in more massive DMHs (log(Mh/[h−1M⊙] )= 11.43−0.10+0.04 log (M h / [ h − 1 M ⊙ ]) = 11. 43 − 0.10 + 0.04 $ \log(M_\mathrm{{h}} / [h^{-1}{M}_{\odot}])=11.43^{+0.04}_{-0.10} $) than the lowest luminosity one (log(LLyα/erg s−1) ≈ 40.97), which presents a bias of blowest = 1.79−0.06+0.08 b lowest = 1. 79 − 0.06 + 0.08 $ b_\mathrm{{lowest}}=1.79^{+0.08}_{-0.06} $ and occupies log(Mh/[h−1M⊙]) = 10.00−0.09+0.12 log (M h / [ h − 1 M ⊙ ]) = 10. 00 − 0.09 + 0.12 $ \log(M_\mathrm{{h}} / [h^{-1}{M}_{\odot}])=10.00^{+0.12}_{-0.09} $ halos. We discuss the implications of these results for evolving Lyα luminosity functions, halo mass dependent Lyα escape fractions, and incomplete reionization signatures. [ABSTRACT FROM AUTHOR]

Context. The 21 cm hydrogen line is arguably one of the most powerful probes with which to explore the Universe, from recombination to the present times. To recover it, it is essential to separate the cosmological signal from the much stronger foreground contributions at radio frequencies. The Baryon Acoustic Oscillations from Integrated Neutral Gas Observations (BINGO) radio telescope is designed to measure the 21 cm line and detect baryon acoustic oscillations (BAOs) using the intensity mapping (IM) technique. Aims. This work analyses the performance of the Generalized Needlet Internal Linear Combination (GNILC) method when combined with a power spectrum debiasing procedure. This method was applied to a simulated BINGO mission, building upon previous work from the collaboration. It compares two different synchrotron emission models and different instrumental configurations and takes into account ancillary data in order to optimize both the removal of foreground emission and the recovery of the 21 cm signal across the full BINGO frequency band and to determine an optimal number of frequency (redshift) bands for the signal recovery. Methods. We produced foreground emission maps using the Planck Sky Model (PSM) and generated cosmological HI emission maps using the Full-Sky Log-normal Astro-Fields simulation Kit (FLASK) package. We also created thermal noise maps according to the instrumental setup. We apply the GNILC method to the simulated sky maps to separate the HI plus thermal noise contribution and, through a debiasing procedure, recover an estimate of the noiseless 21 cm power spectrum. Results. We find a near-optimal reconstruction of the HI signal using an 80-bin configuration, which resulted in a power-spectrum reconstruction average error over all frequencies of 3%. Furthermore, our tests show that GNILC is robust against different synchrotron emission models. Finally, adding an extra channel with C-Band All-Sky Survey (CBASS) foregrounds information, we reduced the estimation error of the 21 cm signal. Conclusions. The optimization of our previous work, producing a configuration with an optimal number of channels for binning the data, significantly impacts decisions regarding BINGO hardware configuration before commissioning. We were able to recover the HI signal with good efficiency in the harmonic space, but have yet to investigate the effect of 1/f noise in the data, which will possibly impact the recovery of the HI signal. This issue will be addressed in forthcoming work. [ABSTRACT FROM AUTHOR]

When Type Ia supernovae are used to infer cosmological parameters, their luminosities are compared to those from a homogeneous cosmology. In this note, we propose a test to examine to what degree SN Ia have been observed on lines of sight where the average matter density is not representative of the homogeneous background. We apply our test to the Pantheon SN Ia compilation, and find two redshift bins which indicate a moderate bias to over-density at ∼2σ. We modify the Tripp estimator to explicitly de-lens SN Ia magnitudes, and show that this reduces scatter of Hubble diagram residuals. Using our revised Tripp estimator, the effect on cosmological parameters from Pantheon in ΛCDM is however small with a change in mean value from Ωm = 0.317 ± 0.027 (baseline) to Ωm = 0.312 ± 0.025 (de-lensed). For the Flat w CDM case, it is Ωm = 0.332 ± 0.049 and w  = −1.16 ± 0.16 (baseline) versus Ωm = 0.316 ± 0.048 and w  = −1.12 ± 0.15 (de-lensed). We note that the effect of lensing on cosmological parameters may be larger for future high-z surveys. [ABSTRACT FROM AUTHOR]

We investigate the capability of Einstein Telescope to constrain the cosmological parameters of the non-flat ΛCDM cosmological model. Two types of mock data sets are considered depending on whether or not a short gamma-ray burst is detected, and associated with the gravitational wave emitted by binary neutron stars merger, using the THESEUS satellite. Depending on the mock data set, two statistical estimators are applied: one assumes that the redshift is known, while the other marginalizes over it assuming a specific redshift prior distribution. We demonstrate that (i) using mock catalogues collecting gravitational wave signals emitted by binary neutron stars systems to which a short gamma-ray burst has been associated, Einstein Telescope may achieve an accuracy on the cosmological parameters of |$\sigma _{H_0}\approx 0.40$| km s−1 Mpc−1, |$\sigma _{\Omega _{k,0}}\approx 0.09$|⁠ , and |$\sigma _{\Omega _{\Lambda ,0}}\approx 0.07$|⁠ ; while (ii) using mock catalogues collecting all gravitational wave signals emitted by binary neutron stars systems for which an electromagnetic counterpart has not been detected, Einstein Telescope may achieve an accuracy on the cosmological parameters of |$\sigma _{H_0}\approx 0.04$| km s−1 Mpc−1, |$\sigma _{\Omega _{k,0}}\approx 0.01$|⁠ , and |$\sigma _{\Omega _{\Lambda ,0}}\approx 0.01$|⁠ , once the redshift probability distribution of GW events is known from from population synthesis simulations and/or the measure of the tidal deformability parameter. These results show an improvement of a factor 2–75 with respect to earlier results using complementary data sets. [ABSTRACT FROM AUTHOR]

We propose a new method to calibrate gamma-ray burst (GRB) correlations employing intermediate redshift data sets, instead of limiting to z ≃ 0 catalogues, and applied it to the well-consolidated Amati correlation. This model-independent calibration technique is based on the Bézier polynomial interpolation of the most updated observational Hubble data and baryonic acoustic oscillations (BAO) and alleviates de facto the well-known circularity problem affecting GRB correlations. In doing so, we also investigate the influence of the BAO scales r s, got from Planck results, and |$r_{\rm s}^{\rm fid}$|⁠ , got from the considered fiducial cosmology, by considering the cases |$(r_{\rm s}/r_{\rm s}^{\rm fid})=1$| and |$(r_{\rm s}/r_{\rm s}^{\rm fid})\ne 1$|⁠. We get constraints on the cosmic parameters, using Markov chain–Monte Carlo simulations, first fixing and then leaving free the spatial curvature density parameter Ωk. Compared to previous literature, we obtain tighter constraints on the mass density parameter Ωm. In particular, our findings turn out to be highly more compatible with those got from standard candle indicators within the Lambda cold dark matter paradigm. Finally, we critically re-examine the recent H 0 tension in view of our outcomes. [ABSTRACT FROM AUTHOR]

The standard Λ cold dark matter (ΛCDM) model is recently reported to deviate from the high-redshift Hubble diagram of Type Ia supernovae (SNe) and quasars (QSOs) at ∼4σ confidence level. In this work, we combine the PAge approximation (a nearly model-independent parametrization) and a high-quality QSO sample to search for the origins of the deviation. By visualizing the ΛCDM model and the marginalized 3σ constraints of SNe+QSOs into the PAge space, we confirm that the SNe+QSO constraints in both flat and non-flat PAge cases are in remarkable tension with the standard ΛCDM cosmology. Next, we investigate the tension from the perspective of redshift-evolution effects. We find that the QSO correlation coefficient γ calibrated by SNe+low- z QSOs and SNe+high- z QSOs shows ∼2.7σ and ∼4σ tensions in flat and non-flat universes, respectively. The tensions for intrinsic dispersion δ between different data sets are found to be >4σ in both flat and non-flat cases. These results indicate that the QSO luminosity correlation suffers from significant redshift evolution and non-universal intrinsic dispersion. Using a redshift-dependence correlation to build QSO Hubble diagram could lead to biases. Thus, the ∼4σ deviation from the standard ΛCDM probably originates from the redshift-evolution effects and non-universal dispersion of the QSO luminosity correlation rather than new physics. [ABSTRACT FROM AUTHOR]

Weak galaxy lensing surveys have consistently reported a lower amplitude for the matter fluctuation spectrum, as measured by the S 8 parameter, than expected in the ΛCDM cosmology favoured by Planck. However, the expansion history follows the predictions of the Planck ΛCDM cosmology to high accuracy, as do measurements of lensing of the cosmic microwave background anisotropies. Redshift space distortion measurements also appear to be consistent with Planck ΛCDM. In this paper, we argue that these observations can be reconciled with the Planck ΛCDM cosmology if the matter power spectrum is suppressed more strongly on non-linear scales than assumed in analyses of weak galaxy lensing. We demonstrate this point by fitting a one-parameter model, characterizing a suppression of the non-linear power spectrum, to the KiDS-1000 weak lensing measurements. Such a suppression could be attributed to new properties of the dark matter that affect non-linear scales, or to a response of the matter fluctuations to baryonic feedback processes that are stronger than expected from recent cosmological simulations. Our proposed explanation can be tested using measurements of the amplitude of the matter fluctuation spectrum on linear scales, in particular via high precision redshift space distortion measurements from forthcoming galaxy and quasar redshift surveys. [ABSTRACT FROM AUTHOR]

We present measurements of the anisotropic cross-correlation of galaxies and cosmic voids in data from the Sloan Digital Sky Survey (SDSS) Main Galaxy Sample, Baryon Oscillation Spectroscopic Survey (BOSS), and extended BOSS luminous red galaxy catalogues from SDSS Data Releases 7, 12, and 16, covering the redshift range 0.07 < z < 1.0. As in our previous work analysing voids in subsets of these data, we use a reconstruction method applied to the galaxy data before void finding in order to remove selection biases when constructing the void samples. We report results of a joint fit to the multipole moments of the measured cross-correlation for the growth rate of structure, f σ8(z), and the ratio D M(z)/ D H(z) of the comoving angular diameter distance to the Hubble distance, in six redshift bins. For D M/ D H, we are able to achieve a significantly higher precision than that obtained from analyses of the baryon acoustic oscillations and galaxy clustering in the same data sets. Our growth rate measurements are of lower precision but still comparable with galaxy clustering results. For both quantities, the results agree well with the expectations for a Λ cold dark matter model. Assuming a flat Universe, our results correspond to a measurement of the matter density parameter |$\Omega _\mathrm{m}=0.337^{+0.026}_{-0.029}$|⁠. For more general models, the degeneracy directions obtained are consistent with and complementary to those from other cosmological probes. These results consolidate void–galaxy cross-correlation measurements as a pillar of modern observational cosmology. [ABSTRACT FROM AUTHOR]

We use 38 C  iv quasar (QSO) reverberation-mapped observations, which span eight orders of magnitude in luminosity and the redshift range 0.001064 ≤ z ≤ 3.368, to simultaneously constrain cosmological-model and QSO radius–luminosity (R–L) relation parameters in six cosmological models, using an improved technique that more correctly accounts for the asymmetric errors bars of the time-lag measurements. We find that R–L relation parameters are independent of the cosmological models used in the analysis and so the R–L relation can be used to standardize the C  iv QSOs. The C  iv QSO cosmological constraints are consistent with those from Mg  ii QSOs, allowing us to derive joint C  iv + Mg  ii QSO cosmological constraints which are consistent with currently accelerated cosmological expansion, as well as consistent with cosmological constraints derived using better-established baryon acoustic oscillation (BAO) and Hubble parameter [ H (z)] measurements. When jointly analysed with H (z) + BAO data, current C  iv + Mg  ii QSO data mildly tighten current H (z) + BAO data cosmological constraints. [ABSTRACT FROM AUTHOR]

Distance-redshift diagrams probe expansion history of the Universe. We show that the stellar mass-binding energy (massE) relation of galaxies proposed in our previous study offers a new distance ruler at cosmic scales. By using elliptical galaxies in the main galaxy sample of the Sloan Digital Sky Survey Data Release 7, we construct a distance-redshift diagram over the redshift range from 0.05 to 0.2 with the massE ruler. The best-fit dark energy density is 0.675 ± 0.079  for flat Λ-cold dark matter (ΛCDM) model, consistent with those by other probes. At the median redshift of 0.11, the median distance is estimated to have a fractional error of 0.34 per cent, much lower than those by supernova (SN) Ia and baryonic acoustic oscillation (BAO) and even exceeding their future capability at this redshift. The above low- |$\mathit{ z}$| measurement is useful for probing dark energy that dominates at the late Universe. For a flat dark energy equation of state model (flat w CDM), the massE alone constrains w to an error that is only a factor of 2.2, 1.7, and 1.3 times larger than those by BAO, SN Ia, and cosmic microwave background (CMB), respectively. [ABSTRACT FROM AUTHOR]

Gamma-ray bursts (GRBs), observed to redshift z = 9.4, are potential probes of the largely unexplored z ∼ 2.7–9.4 part of the early Universe. Thus, finding relevant relations among GRB physical properties is crucial. We find that the Platinum GRB data compilation, with 50 long GRBs (with relatively flat plateaus and no flares) in the redshift range 0.553 ≤ z ≤ 5.0, and the LGRB95 data compilation, with 95 long GRBs in 0.297 ≤ z ≤ 9.4, as well as the 145 GRB combination of the two, strongly favour the 3D Fundamental Plane (Dainotti) correlation (between the peak prompt luminosity, the luminosity at the end of the plateau emission, and its rest-frame duration) over the 2D one (between the luminosity at the end of the plateau emission and its duration). The 3D Dainotti correlations in the three data sets are standardizable. We find that while LGRB95 data have ∼50 per cent larger intrinsic scatter parameter values than the better-quality Platinum data, they provide somewhat tighter constraints on cosmological-model and GRB-correlation parameters, perhaps solely due to the larger number of data points, 95 versus 50. This suggests that when compiling GRB data for the purpose of constraining cosmological parameters, given the quality of current GRB data, intrinsic scatter parameter reduction must be balanced against reduced sample size. [ABSTRACT FROM AUTHOR]

We use observations of 66 reverberation-measured Mg  ii quasars (QSOs) in the redshift range 0.36 ≤ z ≤ 1.686 – a subset of the 78 QSOs we previously studied that also have |${\cal R}_{\rm {Fe\, {\small II}}}$| (flux ratio parameter of UV Fe  ii to Mg  ii that is used as an accretion-rate proxy) measurements – to simultaneously constrain cosmological model parameters and QSO two-parameter and three-parameter radius–luminosity (R – L) relation parameters in six different cosmological models. We find that these QSO R–L relation parameters are independent of the assumed cosmological model and so these QSOs are standardizable through the R – L relations. Also: (1) With the two-parameter R – L relation, we find that the low- |${\cal R}_{\rm {Fe\, {\small II}}}$| and high- |${\cal R}_{\rm {Fe\, {\small II}}}$| data subsets obey the same R – L relation within the error bars. (2) Extending the two-parameter R – L relation to a three-parameter one does not result in the hoped-for reduction in the intrinsic dispersion of the R–L relation. (3) Neither of the three-parameter R – L relations provide a significantly better fit to the measurements than does the two-parameter R – L relation. These are promising results for the ongoing development of Mg  ii cosmological probes. The first and third of these results differ significantly from those we found elsewhere from analyses of reverberation-measured H β QSOs. [ABSTRACT FROM AUTHOR]

Upcoming deep imaging surveys such as the Vera C. Rubin Observatory Legacy Survey of Space and Time will be confronted with challenges that come with increased depth. One of the leading systematic errors in deep surveys is the blending of objects due to higher surface density in the more crowded images; a considerable fraction of the galaxies which we hope to use for cosmology analyses will overlap each other on the observed sky. In order to investigate these challenges, we emulate blending in a mock catalogue consisting of galaxies at a depth equivalent to 1.3 yr of the full 10-yr Rubin Observatory that includes effects due to weak lensing, ground-based seeing, and the uncertainties due to extraction of catalogues from imaging data. The emulated catalogue indicates that approximately 12 per cent of the observed galaxies are 'unrecognized' blends that contain two or more objects but are detected as one. Using the positions and shears of half a billion distant galaxies, we compute shear–shear correlation functions after selecting tomographic samples in terms of both spectroscopic and photometric redshift bins. We examine the sensitivity of the cosmological parameter estimation to unrecognized blending employing both jackknife and analytical Gaussian covariance estimators. An ∼0.025 decrease in the derived structure growth parameter S 8 = σ8(Ωm/0.3)0.5 is seen due to unrecognized blending in both tomographies with a slight additional bias for the photo- z -based tomography. This bias is greater than the 2σ statistical error in measuring S 8. [ABSTRACT FROM AUTHOR]

As the Universe expands, the redshift of distant sources changes with time. Here, we discuss gravitational lensing phenomena that are consequence of the redshift drift between lensed source, gravitational lens, and observer. When the source is located very close to the drifting caustics, a pair of images could occur (or disappear) because of the cosmological expansion. Furthermore, lensing systems act as signal converters of the redshift drift. The angular position, magnification, distortion, and time delay of already existing multiple images change. We estimate the expected frequency of these phenomena and the prospects to observe them in the era of deep and large surveys. The drift detection in image separation could be within reach of next-generation surveys with μarcsec angular resolution. [ABSTRACT FROM AUTHOR]

We use updated Hubble parameter and baryon acoustic oscillation data, as well as other lower redshift Type Ia supernova, Mg  ii reverberation-measured quasar, quasar angular size, H  ii starburst galaxy, and Amati-correlated gamma-ray burst data, to jointly constrain cosmological parameters in six cosmological models. The joint analysis provides model-independent determinations of the Hubble constant, |$H_0=69.7\pm 1.2\, \rm {km \ s^{-1} \ Mpc^{-1}}$| and the current non-relativistic matter density parameter, Ω m 0 = 0.295 ± 0.017. These error bars are factors of 2.2 and 2.3 larger than the corresponding error bars in the flat ΛCDM model from Planck TT,TE,EE+lowE + lensing cosmic microwave background anisotropy data. Based on the deviance information criterion (DIC), the flat ΛCDM model is most favoured but mild dark energy dynamics and a little spatial curvature are not ruled out. [ABSTRACT FROM AUTHOR]

We present clustering redshift measurements for Dark Energy Survey (DES) lens sample galaxies used in weak gravitational lensing and galaxy clustering studies. To perform these measurements, we cross-correlate with spectroscopic galaxies from the Baryon Acoustic Oscillation Survey (BOSS) and its extension, eBOSS. We validate our methodology in simulations, including a new technique to calibrate systematic errors that result from the galaxy clustering bias, and we find that our method is generally unbiased in calibrating the mean redshift. We apply our method to the data, and estimate the redshift distribution for 11 different photometrically selected bins. We find general agreement between clustering redshift and photometric redshift estimates, with differences on the inferred mean redshift found to be below |Δ z | = 0.01 in most of the bins. We also test a method to calibrate a width parameter for redshift distributions, which we found necessary to use for some of our samples. Our typical uncertainties on the mean redshift ranged from 0.003 to 0.008, while our uncertainties on the width ranged from 4 to 9 per cent. We discuss how these results calibrate the photometric redshift distributions used in companion papers for DES Year 3 results. [ABSTRACT FROM AUTHOR]

Gamma-ray bursts (GRBs) are the most luminous objects known: they outshine their host galaxies, making them ideal candidates for probing large-scale structure. Our aim is to determine the Spatial Two-Point Correlation Function of the GRBs with spectroscopic redshifts. We used all observations till 4 June 2021, and we also split the data according to the origin of the redshift (afterglow or host galaxy). We analyzed the possible correlation between the GRB redshift and sky position. There is only one region, called the Faraway GRB Patch, where nine distant GRBs shows deviation from the randomness with an ≈1% significance, showing that the sky and the radial component of the GRB distribution could be factorized and both can be determined independently. The GRBs' cumulative monthly distribution was used to show that it is impossible to synthesize the Sky Exposure Function, even from the perfect observational logs. We estimated the Sky Exposure Function using the Gaussian kernel, and with the radial distribution, it was used for the estimation of the Spatial Two-Point Correlation Function. Monte Carlo simulations were used to determine the Poissonian errors. Our result shows that the current Spatial Two-Point Correlation Function estimations are consistent with zero for the full and the afterglow/host galaxy datasets. [ABSTRACT FROM AUTHOR]

In an age of large astronomical data sets and severe cosmological tensions, the case for model independent analyses is compelling. We present a set of 14 baryon acoustic oscillations measurements in thin redshift shells with |$3\,\mathrm{ per} \,\mathrm{ cent}$| precision that were obtained by analysing BOSS DR12 and eBOSS DR16 galaxies in the redshift range 0.32 < z < 0.66. Thanks to the use of thin shells, the analysis is carried out using just redshifts and angles so that the fiducial model is only introduced when considering the mock catalogues, necessary for the covariance matrix estimation and the pipeline validation. We compare our measurements, with and without supernova data, to the corresponding constraints from Planck 2018, finding good compatibility. A Monte Python module for this likelihood is available at github.com/ranier137/angularBAO. [ABSTRACT FROM AUTHOR]

We use 118 Hβ quasar (QSO) observations in the redshift range 0.0023 ≤ z ≤ 0.89 to simultaneously constrain cosmological model parameters and QSO 2-parameter radius-luminosity (R –L) relation parameters in six different cosmological models. We find that the R –L relation parameters for these QSOs are independent of the assumed cosmology so these QSOs seem to be standardizable through the R –L relation (although there is a complication that might render this untrue). Cosmological constraints obtained using these QSOs are weak, more favour currently decelerated cosmological expansion, and typically are in ∼2σ tension with those obtained from a joint analysis of baryon acoustic oscillation and Hubble parameter measurements. Extending the R –L relation to a 3-parameter one to try to correct for the accretion rate effect does not result in a reduction of the cosmological constraints discrepancy nor does it result in the hoped-for significant reduction of the intrinsic scatter of the R –L relation. [ABSTRACT FROM AUTHOR]

Galaxy redshift surveys are designed to map cosmic structures in three dimensions for large-scale structure studies. Nevertheless, limitations due to sampling and the survey window are unavoidable and degrade the cosmological constraints. We present an analysis of the VIMOS Public Extragalactic Redshift Survey (VIPERS) over the redshift range 0.6 < z < 1 that is optimized to extract the cosmological parameters while fully accounting for the complex survey geometry. We employ the Gibbs sampling algorithm to iteratively draw samples of the galaxy density field in redshift space, the galaxy bias, the matter density, baryon fraction, and growth-rate parameter f σ8 based on a multivariate Gaussian likelihood and prior on the density field. Despite the high number of degrees of freedom, the samples converge to the joint posterior distribution and give self-consistent constraints on the model parameters. We validate the approach using VIPERS mock galaxy catalogues. Although the uncertainty is underestimated by the Gaussian likelihood on the scales that we consider by 50 per cent, the dispersion of the results from the mock catalogues gives a robust error estimate. We find that the precision of the results matches those of the traditional analyses applied to the VIPERS data that use more constrained models. By relaxing the model assumptions, we confirm that the data deliver consistent constraints on the ΛCDM model. This work provides a case-study for the application of maximum-likelihood analyses for the next generation of galaxy redshift surveys. [ABSTRACT FROM AUTHOR]

We investigate the abundance and distribution of metals in the high-redshift intergalactic medium and circum-galactic medium through the analysis of a sample of almost 600 Si  iv absorption lines detected in high- and intermediate-resolution spectra of 147 quasars. The evolution of the number density of Si  iv lines, the column density distribution function, and the cosmic mass density are studied in the redshift interval 1.7 ≲ z ≲ 6.2 and for log  N (Si  iv) ≥ 12.5. All quantities show a rapid increase between z ∼ 6 and z ≲ 5 and then an almost constant behaviour to z ∼ 2 in very good agreement with what is already observed for C  iv absorption lines. The present results are challenging for numerical simulations: When simulations reproduce our Si  iv results, they tend to underpredict the properties of C  iv , and when the properties of C  iv are reproduced, the number of strong Si  iv lines [log  N (Si  iv) > 14] is overpredicted. [ABSTRACT FROM AUTHOR]