Search

We report measurements of the galaxy two-point correlation function at cosmic dawn, using photometrically selected sources from the JWST Advanced Deep Extragalactic Survey (JADES). The JWST/NIRCam data set comprises approximately |$N_g \simeq 7000$| photometrically selected Lyman Break Galaxies (LBGs), spanning in the redshift range |$5\le z\lt 11$|⁠. The primary objective of this study is to extend clustering measurements beyond redshift |$z\gt 10$|⁠ , finding a galaxy bias |$b=9.6\pm 1.7$| for the sample at |$\overline{z} = 10.6$|⁠. The result suggests that the observed sources are hosted by dark matter haloes of approximately |$M_{h}\sim 10^{10.6}~\mathrm{{\rm M}_{\odot }}$|⁠ , in broad agreement with theoretical and numerical modelling of early galaxy formation during the epoch of reionization. Furthermore, the JWST JADES data set enables an unprecedented investigation of clustering of dwarf galaxies two orders of magnitude fainter than the characteristic |$L_*$| luminosity (i.e. with |$M_{F200W}\simeq -15.8$|⁠) during the late stages of the epoch of reionization at |$z\sim 6$|⁠. By analysing clustering as a function of luminosity, we find that |$b(M_{F200W})$| aligns with previous results for brighter galaxies and then decreases with |$M_{F200W}$|⁠ , as theoretically expected for fainter candidates. These initial results demonstrate the potential for further quantitative characterization of the interplay between assembly of dark matter and light during cosmic dawn that the growing samples of JWST observations are enabling. [ABSTRACT FROM AUTHOR]

The most recent SH0ES measurement of the Hubble constant employs corrections of type Ia supernova magnitudes due to extinction in their host galaxies. These corrections are estimated using a probabilistic model which is trained on Hubble flow (⁠|$z\gt 0.03$|⁠) supernovae and extrapolated to the calibration galaxies (those with observed Cepheids), despite the fact that the latter are selected based on criteria favouring discy and dust-rich systems. We show that this standard approach underestimates the brightness of reddened supernovae in the high stellar-mass (⁠|$M_{\star }\gt 10^{10}\, \mathrm{M}_{\odot }$|⁠) calibration galaxies. This can be traced back to the fact that for these galaxies, a low total-to-selective extinction coefficient (⁠|$R_{\rm B}\sim 3$|⁠) is assumed, while for the low stellar-mass analogues a more standard |$R_{\rm B}\sim 4$| is adopted. We propose a minimalistic modification of the extinction model in the calibration galaxies in order to alleviate this systematic effect. The modification is twofold and it involves: (i) the same, Milky Way-like distribution of |$R_{\rm B}$| (with mean |$R_{\rm B}$| of 4.3 – consistent with the extinction curve used for colour corrections of the Cepheids – and scatter 0.4) and (ii) a modified shape of the |$E(B-V)$| reddening distribution while keeping the same effective slope of the supernova peak magnitude–colour relation and the same mean |$E(B-V)$| reddening as measured for supernovae in the Hubble flow. We show that this new approach yields a significantly better fit (⁠|$\Delta \mathrm{ BIC}=-11$|⁠) to the calibration data and results in a lower value of |$H_{0}$|⁠. Our result is |$H_{0}=70.5\pm 1$|  km s |$^{-1}$|  Mpc |$^{-1}$| implying a reduction of the Hubble constant tension from |$5.2\sigma$| to |$2.8\sigma$|⁠. [ABSTRACT FROM AUTHOR]

The most recent SH0ES measurement of the Hubble constant employs corrections of type Ia supernova magnitudes due to extinction in their host galaxies. These corrections are estimated using a probabilistic model which is trained on Hubble flow (⁠|$z\gt 0.03$|⁠) supernovae and extrapolated to the calibration galaxies (those with observed Cepheids), despite the fact that the latter are selected based on criteria favouring discy and dust-rich systems. We show that this standard approach underestimates the brightness of reddened supernovae in the high stellar-mass (⁠|$M_{\star }\gt 10^{10}\, \mathrm{M}_{\odot }$|⁠) calibration galaxies. This can be traced back to the fact that for these galaxies, a low total-to-selective extinction coefficient (⁠|$R_{\rm B}\sim 3$|⁠) is assumed, while for the low stellar-mass analogues a more standard |$R_{\rm B}\sim 4$| is adopted. We propose a minimalistic modification of the extinction model in the calibration galaxies in order to alleviate this systematic effect. The modification is twofold and it involves: (i) the same, Milky Way-like distribution of |$R_{\rm B}$| (with mean |$R_{\rm B}$| of 4.3 – consistent with the extinction curve used for colour corrections of the Cepheids – and scatter 0.4) and (ii) a modified shape of the |$E(B-V)$| reddening distribution while keeping the same effective slope of the supernova peak magnitude–colour relation and the same mean |$E(B-V)$| reddening as measured for supernovae in the Hubble flow. We show that this new approach yields a significantly better fit (⁠|$\Delta \mathrm{ BIC}=-11$|⁠) to the calibration data and results in a lower value of |$H_{0}$|⁠. Our result is |$H_{0}=70.5\pm 1$|  km s |$^{-1}$|  Mpc |$^{-1}$| implying a reduction of the Hubble constant tension from |$5.2\sigma$| to |$2.8\sigma$|⁠. [ABSTRACT FROM AUTHOR]

Exploring the marks left by galactic accretion in the Milky Way helps us understand how our Galaxy was formed. However, finding and studying accreted stars and the galaxies they came from has been challenging. This study uses a simulation from the Numerical Investigation of a Hundred Astronomical Objects project, which now includes a wider range of chemical compositions, to find better ways to spot these accreted stars. By comparing our findings with data from the GALAH spectroscopic survey, we confirm that the observationally established diagnostics of [Al/Fe] versus [Mg/Mn] also show a separation of in situ and accreted stars in the simulation, but stars from different accretion events tend to overlap in this plane even without observational uncertainties. Looking at the relationship between stellar age and linear or logarithmic abundances, such as [Fe/H], we can clearly separate different groups of these stars if the uncertainties in their chemical makeup are less than 0.15 dex and less than 20 per cent for their ages. This method shows promise for studying the history of the Milky Way and other galaxies. Our work highlights how important it is to have accurate measurements of stellar ages and chemical content. It also shows how simulations can help us understand the complex process of galaxies merging and suggest how these events might relate to the differences we see between our Galaxy's thin and thick disc stars. This study provides a way to compare theoretical models with real observations, opening new paths for research in both our own Galaxy and beyond. [ABSTRACT FROM AUTHOR]

Fitting model spectral energy distributions (SEDs) to galaxy photometric data is a widely used method to recover galaxy parameters from galaxy surveys. However, the parameter space used to describe galaxies is wide and interdependent, and distinctions between real and spurious correlations that are found between these parameters can be difficult to discern. In this work, we use the SED fitting code bagpipes (Bayesian Analysis of Galaxies for Physical Inference and Parameter EStimation) to investigate degeneracies between galaxy parameters and the effect of the choice of different sets of photometric bands. In particular, we focus on optical to infrared wavelength coverage, and on two parameters describing the galaxies' dust attenuation law: AV and δ, which characterize dust column density and the slope of a flexible dust attenuation law, respectively. We demonstrate that (1) a degeneracy between the residual (the difference between truth and recovered values) AV and star formation rate exists, but this is lifted when Wide-Field Infrared Survey Explorer bands are included, and (2) bagpipes is able to accurately recover the input AV and δ distributions and relations (differences in slope of less than 1.7σ for a flat relation and less than 1.2σ for an observationally motivated relation) and is not introducing spurious correlations between these parameters. Our findings suggest that the information needed to constrain AV and δ well enough individually exists in the data, especially when infrared is added. This indicates that recent works finding a correlation between AV and δ are not being misled by fitting degeneracies from their SED fitting code. [ABSTRACT FROM AUTHOR]

JWST has recently sparked a new era of Lyα spectroscopy, delivering the first measurements of the Lyα escape fraction and velocity profile in typical galaxies at z ≃ 6−10. These observations offer new prospects for insight into the earliest stages of reionization. But to realize this potential, we need robust models of Lyα properties in galaxies at z ≃ 5−6 when the IGM is mostly ionized. Here, we use new JWST observations from the JADES and FRESCO surveys combined with VLT/MUSE and Keck/DEIMOS data to characterize statistical distributions of Lyα velocity offsets, escape fractions, and EWs in z ≃ 5−6 galaxies. We find that galaxies with large Lyα escape fractions (>0.2) are common at z ≃ 5−6, comprising 30 per cent of Lyman break selected samples. Comparing to literature studies, our census suggests that Lyα becomes more prevalent in the galaxy population towards higher redshift from z ∼ 3 to z ∼ 6, although we find that this evolution slows considerably between z ∼ 5 and z ∼ 6, consistent with modest attenuation from residual H i in the mostly ionized IGM at z ≃ 5−6. We find significant evolution in Lyα velocity profiles between z ≃ 2−3 and z ≃ 5−6, likely reflecting the influence of resonant scattering from residual intergalactic H i on the escape of Lyα emission near line centre. This effect will make it challenging to use Lyα peak offsets as a probe of Lyman continuum leakage at z ≃ 5−6. We use our z ≃ 5−6 Lyα distributions to make predictions for typical Lyα properties at z ≳ 8 and discuss implications of a recently discovered Lyα emitter at z ≃ 8.5 with a small peak velocity offset (156 km s−1). [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 present observational evidence of the impact of triaxiality on radial profiles that extend to 40 Mpc from galaxy cluster centres in optical measurements. We perform a stacked profile analysis from a sample of thousands of nearly relaxed galaxy clusters from public data releases of the Dark Energy Survey and the Dark Energy Camera Legacy Survey. Using the central galaxy elliptical orientation angle as a proxy for galaxy cluster orientation, we measure cluster weak lensing and excess galaxy density axis-aligned profiles, extracted along the central galaxy's major or minor axes on the plane of the sky. Our measurements show a ≳ 2σ–3σ difference per radial bin between the normalized axis-aligned profiles. The profile difference between each axis-aligned profile and the azimuthally averaged profile (⁠|$\sim \pm 10\,\rm per\ cent-20~{{\ \rm per\ cent}}$| along major/minor axis) appears inside the clusters (∼0.4 Mpc) and extends to the large-scale structure regime (∼10–20 Mpc). The magnitude of the difference appears to be relatively insensitive to cluster richness and redshift, and extends further out in the weak lensing surface mass density than in the galaxy overdensity. Looking forward, this measurement can easily be applied to other observational or simulation data sets and can inform the systematics in cluster mass modelling related to triaxiality. We expect imminent upcoming wide-area deep surveys, such as the Vera C. Rubin Observatory's Legacy Survey of Space and Time, to improve our quantification of optical signatures of cluster triaxiality. [ABSTRACT FROM AUTHOR]

The baryon acoustic oscillations (BAOs) phenomenon provides a unique opportunity to establish a standard ruler at any epoch in the history of the evolving universe. The key lies in identifying a suitable cosmological tracer to conduct the measurement. In this study, we focus on quantifying the sound horizon scale of BAO in the Local Universe. Our chosen cosmological tracer is a sample of blue galaxies from the Sloan Digital Sky Survey (SDSS), positioned at the effective redshift |$z_{{\rm eff}} = 0.166$|⁠. Utilizing Planck-CMB input values for redshift-to-distance conversion, we derive the BAO scale |$s_{{\rm BAO}} = 100.28 ^{+10.79} _{-22.96}$| Mpc h −1 at the 1 |$\sigma$| confidence level. Subsequently, we extrapolate the BAO signal scale in redshift space: |$\Delta z_{{\rm BAO}}(z_{\rm eff}=0.166)=0.0361^{+0.00262}_ {-0.0055}$|⁠. This measurement holds the potential to discriminate among dark energy models within the Local Universe. To validate the robustness of our methodology for BAO scale measurement, we conduct three additional BAO analyses using different cosmographic approaches for distance calculation from redshifts. These tests aim to identify possible biases or systematics in our measurements of |$s_{{\rm BAO}}$|⁠. Encouragingly, our diverse cosmographic approaches yield results in statistical agreement with the primary measurement, indicating no significant deviations. Conclusively, our study contributes with a novel determination of the BAO scale in the Local Universe, at |$z_{{\rm eff}} = 0.166$|⁠ , achieved through the analysis of the SDSS blue galaxies cosmic tracer. [ABSTRACT FROM AUTHOR]

Aims. We derived galaxy colour selections from Euclid and ground-based photometry, aiming to accurately define background galaxy samples in cluster weak-lensing analyses. These selections have been implemented in the Euclid data analysis pipelines for galaxy clusters. Methods. Given any set of photometric bands, we developed a method for the calibration of optimal galaxy colour selections that maximises the selection completeness, given a threshold on purity. Such colour selections are expressed as a function of the lens redshift. Results. We calibrated galaxy selections using simulated ground-based griz and EuclidYEJEHE photometry. Both selections produce a purity higher than 97%. The griz selection completeness ranges from 30% to 84% in the lens redshift range zl ∈ [0.2, 0.8]. With the full grizYEJEHE selection, the completeness improves by up to 25 percentage points, and the zl range extends up to zl = 1.5. The calibrated colour selections are stable to changes in the sample limiting magnitudes and redshift, and the selection based on griz bands provides excellent results on real external datasets. Furthermore, the calibrated selections provide stable results using alternative photometric aperture definitions obtained from different ground-based telescopes. The griz selection is also purer at high redshift and more complete at low redshift compared to colour selections found in the literature. We find excellent agreement in terms of purity and completeness between the analysis of an independent, simulated Euclid galaxy catalogue and our calibration sample, except for galaxies at high redshifts, for which we obtain up to 50 percentage points higher completeness. The combination of colour and photo-z selections applied to simulated Euclid data yields up to 95% completeness, while the purity decreases down to 92% at high zl. We show that the calibrated colour selections provide robust results even when observations from a single band are missing from the ground-based data. Finally, we show that colour selections do not disrupt the shear calibration for stage III surveys. The first Euclid data releases will provide further insights into the impact of background selections on the shear calibration. [ABSTRACT FROM AUTHOR]

Estimating a reliable covariance matrix for correlation functions of galaxies is a crucial task to obtain accurate cosmological constraints from galaxy surveys. We generate 2000 independent light-cone mock luminous red galaxy (LRGs) catalogues at 0.3 ≤ z ≤ 1.25, designed to cover CAMIRA LRGs observed by the Subaru Hyper Suprime-Cam Subaru Strategic Programme (HSC SSP). We first produce full-sky light-cone halo catalogues using a COmoving Lagrangian Acceleration (COLA) technique, and then trim them to match the footprints of the HSC SSP S20A Wide layers. The mock LRGs are subsequently populated on to the trimmed halo catalogues according to the halo occupation distribution model constrained by the observed CAMIRA LRGs. The stellar mass (M ⋆) is assigned to each LRG by the subhalo abundance-matching technique using the observed stellar-mass functions of CAMIRA LRGs. We evaluate photometric redshifts (photo- z) of mock LRGs by incorporating the photo- z scatter, which is derived from the observed M ⋆–photo- z -scatter relations of the CAMIRA LRGs. We validate the constructed full-sky halo and light-cone LRG mock catalogues by comparing their angular clustering statistics (i.e. power spectra and correlation functions) with those measured from the halo catalogues of full N -body simulations and the CAMIRA LRG catalogues from the HSC SSP, respectively. We detect clear signatures of baryon acoustic oscillations (BAOs) from our mock LRGs, whose angular scales are well consistent with theoretical predictions. These results demonstrate that our mock LRGs can be used to evaluate covariance matrices at large scales and provide predictions for the BAO detectability and cosmological constraints. [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]

We apply the marked correlation function test proposed by Armijo et al. (Paper I) to samples of luminous red galaxies (LRGs) from the final data release of the Sloan Digital Sky Survey (SDSS) III. The test assigns a density-dependent mark to galaxies in the estimation of the projected marked correlation function. Two gravity models are compared: general relativity (GR) and |$f(R)$| gravity. We build mock catalogues which, by construction, reproduce the measured galaxy number density and two-point correlation function of the LRG samples, using the halo occupation distribution model (HOD). A range of HOD models give acceptable fits to the observational constraints, and this uncertainty is fed through to the error in the predicted marked correlation functions. The uncertainty from the HOD modelling is comparable to the sample variance for the SDSS-III LRG samples. Our analysis shows that current galaxy catalogues are too small for the test to distinguish a popular |$f(R)$| model from GR. However, upcoming surveys with a better measured galaxy number density and smaller errors on the two-point correlation function, or a better understanding of galaxy formation, may allow our method to distinguish between viable gravity models. [ABSTRACT FROM AUTHOR]

Weak gravitational lensing of distant galaxies provides a powerful probe of dark energy. The aim of this study is to investigate the application of convolutional neural networks (CNNs) to precision shear estimation. In particular, using a shallow CNN, we explore the impact of point spread function (PSF) misestimation and 'galaxy population bias' (including 'distribution bias' and 'morphology bias'), focusing on the accuracy requirements of next generation surveys. We simulate a population of noisy disc and elliptical galaxies and adopt a PSF that is representative of a Euclid -like survey. We quantify the accuracy achieved by the CNN, assuming a linear relationship between the estimated and true shears and measure the multiplicative (m) and additive (c) biases. We make use of an unconventional loss function to mitigate the effects of noise bias and measure m and c when we use either: (i) an incorrect galaxy ellipticity distribution or size–magnitude relation, or the wrong ratio of morphological types, to describe the population of galaxies (distribution bias); (ii) an incorrect galaxy light profile (morphology bias); or (iii) a PSF with size or ellipticity offset from its true value (PSF misestimation). We compare our results to the Euclid requirements on the knowledge of the PSF model shape and size. Finally, we outline further work to build on the promising potential of CNNs in precision shear estimation. [ABSTRACT FROM AUTHOR]

Cross-correlation between weak lensing of the Cosmic Microwave Background (CMB) and weak lensing of galaxies offers a way to place robust constraints on cosmological and astrophysical parameters with reduced sensitivity to certain systematic effects affecting individual surveys. We measure the angular cross-power spectrum between the Atacama Cosmology Telescope (ACT) DR4 CMB lensing and the galaxy weak lensing measured by the Dark Energy Survey (DES) Y3 data. Our baseline analysis uses the CMB convergence map derived from ACT-DR4 and Planck data, where most of the contamination due to the thermal Sunyaev Zel'dovich effect is removed, thus avoiding important systematics in the cross-correlation. In our modelling, we consider the nuisance parameters of the photometric uncertainty, multiplicative shear bias and intrinsic alignment of galaxies. The resulting cross-power spectrum has a signal-to-noise ratio = 7.1 and passes a set of null tests. We use it to infer the amplitude of the fluctuations in the matter distribution (S 8 ≡ σ8(Ωm/0.3)0.5 = 0.782 ± 0.059) with informative but well-motivated priors on the nuisance parameters. We also investigate the validity of these priors by significantly relaxing them and checking the consistency of the resulting posteriors, finding them consistent, albeit only with relatively weak constraints. This cross-correlation measurement will improve significantly with the new ACT-DR6 lensing map and form a key component of the joint 6×2pt analysis between DES and ACT. [ABSTRACT FROM AUTHOR]

Models derived in 2009 to fit mid-infrared (8–24 micron) source counts from the IRAS, ISO, and Spitzer missions, provide an excellent fit to deep counts with JWST , demonstrating that the evolution of dusty star-forming galaxies is well understood. The evolution of dust in galaxies at high redshifts is discussed and a simple prescription is proposed to model this. This allows more realistic models for source-counts at submillimetre wavelength. A reasonable fit to 250, 500, 850, and 1100 micron counts is obtained. This paper therefore draws together the IRAS, ISO, Spitzer, Akari, Herschel , submillimetre ground-based, and JWST surveys into a single picture. [ABSTRACT FROM AUTHOR]

We report the discovery of 40 new satellite dwarf galaxy candidates in the sphere of influence of the Sombrero Galaxy (M104), the most luminous galaxy in the Local Volume. Using the Subaru Hyper Suprime-Cam, we surveyed 14.4 deg2 of its surroundings, extending to the virial radius. Visual inspection of the deep images and galfit modelling yielded a galaxy sample highly complete down to Mg ∼ −9 (⁠|$L_{g}\sim 3\times 10^{5}\ \mathrm{ L}_\odot$|⁠) and spanning magnitudes −16.4 < Mg < −8 and half-light radii 50 pc < r e < 1600 pc assuming the distance of M104. These 40 new candidates, out of which 27 are group members with high confidence, double the number of potential satellites of M104 within the virial radius, placing it among the richest hosts in the Local Volume. Using a principal component analysis, we find that the entire sample of candidates is consistent with an almost circular on-sky distribution, more circular than any comparable environment found in the Illustris TNG100-1 (The Next Generation) simulation. However, the distribution of the high-probability sample is more oblate and consistent with the simulation. The cumulative satellite luminosity function is broadly consistent with analogues from the simulation, albeit it contains no bright satellite with Mg < −16.4 (⁠|$L_{g}\sim 3 \times 10^{8}\ \mathrm{ L}_\odot$|⁠), a |$2.3\, \sigma$| occurrence. Follow-up spectroscopy to confirm group membership will begin to demonstrate how these systems can act as probes of the structure and formation history of the halo of M104. [ABSTRACT FROM AUTHOR]

We infer the connection between stellar mass of galaxies from Subaru Hyper Suprime-Cam (HSC) survey, and their dark matter halo masses in two bins of redshifts between [0.3, 0.8]. We use measurements of the weak lensing of background galaxies from Year-1 shape catalogue from the HSC survey. We bin lens galaxies in stellar mass with varying thresholds ranging from |$8.6\le \log [M_*/(h^{-2}{M_\odot })]\le \, 11.2$| and use stringent cuts in the selection of source galaxies to measure the lensing signal. We model these measurements of the lensing signals together with the abundance of galaxies in the halo occupation distribution framework. We obtain constraints on the halo occupation parameters of central galaxies M min and σlog  M along with parameters that describe the occupation of the satellite galaxies. The measurements of abundance and lensing individually constrain different degeneracy directions in M min− σlog  M plane, thus breaking the degeneracy in these parameters. We demonstrate that the lensing measurements are best able to constrain average central halo masses, 〈 M cen〉. We compare our measurements to those obtained using the abundance and clustering of these galaxies. We find that the galaxy–dark matter connection does not vary significantly between redshift bins we explore in this study. Uncertainties in the photometric redshift of the lens galaxies need to be studied to understand the true underlying stellar mass–halo mass relation and evolution of galaxies. [ABSTRACT FROM AUTHOR]

For over a decade there have been contradictory claims in the literature about whether the local bulk flow motion of galaxies is consistent or in tension with the ΛCDM model. While it has become evident that systematics affect bulk flow measurements, systematics in the estimators have not been widely investigated. In this work, we thoroughly evaluate the performance of four estimator variants, including the Kaiser maximum likelihood estimator (MLE) and the minimum variance estimator (MVE). We find that these estimators are unbiased, however their precision may be strongly correlated with the survey geometry. Small biases in the estimators can be present leading to underestimated bulk flows, which we suspect are due to the presence of non-linear peculiar velocities. The uncertainty assigned to the bulk flows from these estimators is typically underestimated, which leads to an overestimate of the tension with ΛCDM. We estimate the bulk flow for the CosmicFlows–4 data and use mocks to ensure the uncertainties are appropriately accounted for. Using the MLE we find a bulk flow amplitude of 408 ± 165 kms−1 at a depth of |$49\, \mathrm{Mpc} h^{-1}$|⁠ , in reasonable agreement with ΛCDM. However using the MVE which can probe greater effective depths, we find an amplitude of 428 ± 108 kms−1 at a depth of |$173\, \mathrm{Mpc} h^{-1}$|⁠ , in tension with the model, having only a 0.11 per cent probability of obtaining a larger χ2. These measurements appear directed towards the Great Attractor region where more data may be needed to resolve tensions. [ABSTRACT FROM AUTHOR]

We describe new JWST /NIRSpec observations of galaxies at z ≳ 7 taken from the CEERS survey. Previous observations of this area have revealed associations of Lyα emitters at redshifts (z = 7.5, 7.7, and 8.7) where the intergalactic medium (IGM) is thought to be mostly neutral, leading to suggestions that these systems are situated in large ionized bubbles. We identify 21 z ≳ 7 galaxies with robust redshifts in the CEERS data set, including 10 in the Lyα associations. Their spectra are indicative of very highly ionized and metal poor gas, with line ratios (O32 = 17.84 and Ne3O2 = 0.89, linear scale) and metallicity (⁠|$12+\log {(\rm {O/H})}=7.84$|⁠) that are rarely seen at lower redshifts. We find that the most extreme spectral properties are found in the six z ≳ 7 Lyα emitters in the sample. Each has a hard ionizing spectrum indicating that their visibility is likely enhanced by efficient ionizing photon production. Lyα velocity offsets are found to be very large (≳300 km s−1), likely also contributing to their detectability. We find that Lyα in z ≳ 7 galaxies is 6–12 × weaker than in lower redshift samples with matched rest-optical spectral properties. If the bubbles around the Lyα emitters are relatively small (≲0.5–1 pMpc), we may expect such significant attenuation of Lyα in these ionized regions. We discuss several other effects that may contribute to weaker Lyα emission at z ≳ 7. Deep spectroscopy of fainter galaxies in the vicinity of the Lyα emitters will better characterize the physical scale of the ionized bubbles in this field. [ABSTRACT FROM AUTHOR]

Clusters of galaxies trace the most non-linear peaks in the cosmic density field. The weak gravitational lensing of background galaxies by clusters can allow us to infer their masses. However, galaxies associated with the local environment of the cluster can also be intrinsically aligned due to the local tidal gradient, contaminating any cosmology derived from the lensing signal. We measure this intrinsic alignment in Dark Energy Survey (DES) Year 1 redMaPPer clusters. We find evidence of a non-zero mean radial alignment of galaxies within clusters between redshifts 0.1–0.7. We find a significant systematic in the measured ellipticities of cluster satellite galaxies that we attribute to the central galaxy flux and other intracluster light. We attempt to correct this signal, and fit a simple model for intrinsic alignment amplitude (A IA) to the measurement, finding A IA = 0.15 ± 0.04, when excluding data near the edge of the cluster. We find a significantly stronger alignment of the central galaxy with the cluster dark matter halo at low redshift and with higher richness and central galaxy absolute magnitude (proxies for cluster mass). This is an important demonstration of the ability of large photometric data sets like DES to provide direct constraints on the intrinsic alignment of galaxies within clusters. These measurements can inform improvements to small-scale modelling and simulation of the intrinsic alignment of galaxies to help improve the separation of the intrinsic alignment signal in weak lensing studies. [ABSTRACT FROM AUTHOR]

We investigate the clustering properties of 3 < z < 5 candidate passive galaxies from the Merlin et al. (2019) sample residing in the GOODS-North (35 sources) and GOODS-South (33 sources) fields. Within the large uncertainties due to the paucity of sources we do not detect clustering signal in GOODS-North, while this is present in GOODS-South, highlighting the importance of the effects of cosmic variance. The estimated correlation length in GOODS-South is |$r_0=12^{+4}_{-5}$|  Mpc, while the estimated minimum mass for a halo capable to host one of such high-redshift quenched galaxies is log10(M min/M⊙) = 13.0 ± 0.3, once also the constraints from their space density are taken into account. Both values are compatible with the results from GOODS-North. Putting the above findings in a cosmological context, these suggest no evolution of the dark matter content of the hosts of passive galaxies during the past 12.5 Gyr, i.e. during more than 90 per cent of the age of the Universe. We discuss possible scenarios for the observed trend. [ABSTRACT FROM AUTHOR]

Several analyses have shown that Λ cold dark matter-based models cannot jointly describe the clustering (GC) and galaxy–galaxy lensing (GGL) of galaxies in the Sloan Digital Sky Survey-III (SDSS-III) Baryon Oscillation Spectroscopic Survey (BOSS), which is commonly known as the 'lensing-is-low problem'. In this work, we show that an extension of Subhalo Abundance Matching, dubbed SHAMe, successfully solves this problem. First, we show that this model accurately reproduces the GC and GGL of a mock galaxy sample in the TNG300 hydrodynamic simulation with properties analogous to those of BOSS galaxies. Then, we switch our attention to observed BOSS galaxies at z  = 0.31−0.43, and we attempt to reproduce their GC and GGL by evaluating SHAMe on two different simulations: one adopting best-fitting cosmological parameters from Planck and the other from weak gravitational lensing surveys (Low S8), where the amplitude of matter fluctuations is lower for the latter. We find excellent agreement between SHAMe predictions and observations for both cosmologies, indicating that the lensing-is-low problem originates from approximations in previous theoretical descriptions of the data. The main difference between SHAMe results in these cosmologies is the level of galaxy assembly bias, which is approximately 20 per cent and 10 per cent for Planck and Low S8, respectively. These results highlight the dangers of employing oversimplified models to analyse current large-scale structure data sets, and the need for realistic yet flexible descriptions of the galaxy–halo connection. [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 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 present, for the first time, an observational test of the consistency relation for the large-scale structure (LSS) of the Universe through a joint analysis of the anisotropic two- and three-point correlation functions (2PCF and 3PCF) of galaxies. We parameterize the breakdown of the LSS consistency relation in the squeezed limit by E s, which represents the ratio of the coefficients of the shift terms in the second-order density and velocity fluctuations. E s ≠ 1 is a sufficient condition under which the LSS consistency relation is violated. A novel aspect of this work is that we constrain E s by obtaining information about the non-linear velocity field from the quadrupole component of the 3PCF without taking the squeezed limit. Using the galaxy catalogues in the Baryon Oscillation Spectroscopic Survey (BOSS) Data Release 12, we obtain |$E_{\rm s} = -0.92_{-3.26}^{+3.13}$|⁠ , indicating that there is no violation of the LSS consistency relation in our analysis within the statistical errors. Our parameterization is general enough that our constraint can be applied to a wide range of theories, such as multicomponent fluids, modified gravity theories, and their associated galaxy bias effects. Our analysis opens a new observational window to test the fundamental physics using the anisotropic higher-order correlation functions of galaxy clustering. [ABSTRACT FROM AUTHOR]

We present the first clustering measurement of Strong Blended Lyman α (SBLA) absorption systems by measuring their cross-correlation with the Lyman α forest. SBLAs are a new population of absorbers detected within the Lyman α forest. We find a bias of 2.329 ± 0.057, consistent with that of Damped Lyman α absorbers (DLAs). For DLAs, we recover a bias of 2.331 ± 0.057 larger than previously reported. We also find a redshift space distortion parameter β = 0.417 ± 0.010, also consistent with the recovered value for DLAs (β = 0.416 ± 0.010). This is consistent with SBLA and DLA systems tracing different portions of the circumgalactic medium of a broadly common population of galaxies. Given these common clustering properties, we combined them to perform a cross-correlation of galaxies in absorption with the Lyα forest. We find that the BAO scale uncertainty of this new measurement is 1.75 × that of Lyα autocorrelation and 1.6 × that of the quasar cross-correlation with the Lyα forest. We note that the current preferred metal contamination model for fitting the correlation functions with respect to the Lyα forest is not realistic enough for SBLA systems, likely due to their status as high redshift precision sites of high metal enrichment. Mock spectra including SBLA systems and their associated metal absorption are required to understand this sample fully. We conclude that SBLAs have the potential to complement the standard Lyα cosmological analyses in future surveys. [ABSTRACT FROM AUTHOR]

We probed the dynamical mass profiles of ten galaxy clusters from the HIghest X-ray FLUx Galaxy Cluster Sample (HIFLUGCS) using galaxy kinematics. We numerically solved the spherical Jeans equation and parameterize the dynamical mass profile and the galaxy velocity anisotropy profile using two general functions to ensure that our results are not biased toward any specific model. The mass-velocity anisotropy degeneracy is ameliorated by using two "virial shape parameters" that depend on the fourth moment of velocity distribution. The resulting velocity anisotropy estimates consistently show a nearly isotropic distribution in the inner regions, with an increasing radial anisotropy toward large radii. We compared our derived dynamical masses with those calculated from X-ray gas data assuming hydrostatic equilibrium, finding that massive and rich relaxed clusters generally present consistent mass measurements, while unrelaxed or low-richness clusters have systematically larger total masses than hydrostatic masses by, on average, 50%. This might help alleviate current tensions in the measurement of σ8, but it also leads to cluster baryon fractions below the cosmic value. Finally, our approach probes accelerations as low as 10−11 m s−2, comparable to the outskirts of individual late-type galaxies. We confirm that galaxy clusters deviate from the radial acceleration relation defined by galaxies. [ABSTRACT FROM AUTHOR]

We report a new test of modified gravity theories using the large-scale structure of the Universe. This paper is the first attempt to (1) apply a joint analysis of the anisotropic components of galaxy two- and three-point correlation functions (2 and 3PCFs) to actual galaxy data and (2) constrain the non-linear effects of degenerate higher-order scalar-tensor (DHOST) theories on cosmological scales. Applying this analysis to the Baryon Oscillation Spectroscopic Survey (BOSS) data release 12, we obtain the lower bounds of −1.655 < ξt and −0.504 < ξs at the |$95{{\ \rm per\ cent}}$| confidence level on the parameters characterizing the time evolution of the tidal and shift terms of the second-order velocity field. These constraints are consistent with GR predictions of ξt = 15/1144 and ξs = 0. Moreover, they represent a 35-fold and 20-fold improvement, respectively, over the joint analysis with only the isotropic 3PCF. We ensure the validity of our results by investigating various quantities, including theoretical models of the 3PCF, window function corrections, cumulative S/N, Fisher matrices, and statistical scattering effects of mock simulation data. We also find statistically significant discrepancies between the BOSS data and the Patchy mocks for the 3PCF measurement. Finally, we package all of our 3PCF analysis codes under the name hitomi and make them publicly available so that readers can reproduce all the results of this paper and easily apply them to ongoing future galaxy surveys. [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]

A tetrahedron is the simplest shape that cannot be rotated into its mirror image in three-dimension (3D). The 4-point correlation function (4PCF), which quantifies excess clustering of quartets of galaxies over random, is the lowest order statistic sensitive to parity violation. Each galaxy defines one vertex of the tetrahedron. Parity-odd modes of the 4PCF probe an imbalance between tetrahedra and their mirror images. We measure these modes from the largest currently available spectroscopic samples, the 280 067 luminous red galaxies (LRGs) of the Baryon Oscillation Spectroscopic Survey (BOSS) twelfth data release (DR12) LOWZ (⁠|$\bar{z} = 0.32$|) and the 803 112 LRGs of BOSS DR12 CMASS (⁠|$\bar{z} = 0.57$|). In LOWZ, we find 3.1σ evidence for a non-zero parity-odd 4PCF, and in CMASS we detect a parity-odd 4PCF at 7.1σ. Gravitational evolution alone does not produce this effect; parity-breaking in LSS, if cosmological in origin, must stem from the epoch of inflation. We have explored many sources of systematic error and found none that can produce a spurious parity-odd signal sufficient to explain our result. Underestimation of the noise could also lead to a spurious detection. Our reported significances presume that the mock catalogues used to calculate the covariance sufficiently capture the covariance of the true data. We have performed numerous tests to explore this issue. The odd-parity 4PCF opens a new avenue for probing new forces during the epoch of inflation with 3D large-scale structure; such exploration is timely given large upcoming spectroscopic samples such as Dark Energy Spectroscopic Instrument and Euclid. [ABSTRACT FROM AUTHOR]

We cross-correlate positions of galaxies measured in data from the first three years of the Dark Energy Survey with Compton- y maps generated using data from the South Pole Telescope (SPT) and the Planck mission. We model this cross-correlation measurement together with the galaxy autocorrelation to constrain the distribution of gas in the Universe. We measure the hydrostatic mass bias or, equivalently, the mean halo bias-weighted electron pressure 〈 bh Pe 〉, using large-scale information. We find 〈 bh Pe 〉 to be |$[0.16^{+0.03}_{-0.04},0.28^{+0.04}_{-0.05},0.45^{+0.06}_{-0.10},0.54^{+0.08}_{-0.07},0.61^{+0.08}_{-0.06},0.63^{+0.07}_{-0.08}]$| meV cm−3 at redshifts z ∼ [0.30, 0.46, 0.62, 0.77, 0.89, 0.97]. These values are consistent with previous work where measurements exist in the redshift range. We also constrain the mean gas profile using small-scale information, enabled by the high-resolution of the SPT data. We compare our measurements to different parametrized profiles based on the cosmo-OWLS hydrodynamical simulations. We find that our data are consistent with the simulation that assumes an AGN heating temperature of 108.5 K but are incompatible with the model that assumes an AGN heating temperature of 108.0 K. These comparisons indicate that the data prefer a higher value of electron pressure than the simulations within r 500 c of the galaxies' haloes. [ABSTRACT FROM AUTHOR]

Shear estimation bias from galaxy detection and blending identification is now recognized as an issue for ongoing and future weak-lensing surveys. Currently, the empirical approach to correcting for this bias involves numerically shearing every observed galaxy and rerunning the detection and selection process. In this work, we provide an analytical correction for this bias that is accurate to sub per cent level and far simpler to use. With the interpretation that smoothed image pixel values and galaxy properties are projections of the image signal onto a set of basis functions, we analytically derive the linear shear responses of both the pixel values and the galaxy properties (i.e. magnitude, size, and shape) using the shear responses of the basis functions. With these derived shear responses, we correct for biases from shear-dependent galaxy detection and galaxy sample selection. With the analytical covariance matrix of measurement errors caused by image noise on pixel values and galaxy properties, we correct for the noise biases in galaxy shape measurement and the detection/selection process to the second-order in noise. The code used for this paper can carry out the detection, selection, and shear measurement for ∼1000 galaxies per CPU second. The algorithm is tested with realistic image simulations, and we find, after the analytical correction (without relying on external image calibration) for the detection/selection bias of about |$-4~{{\ \rm per\ cent}}$|⁠ , the multiplicative shear bias is |$-0.12 \pm 0.10~{{\ \rm per\ cent}}$| for isolated galaxies; and about |$-0.3 \pm 0.1~{{\ \rm per\ cent}}$| for blended galaxies with Hyper Suprime-Cam observational condition. [ABSTRACT FROM AUTHOR]

Optical clusters identified from red-sequence galaxies suffer from projection effects, where interloper galaxies along the line of sight to a cluster are mistaken as genuine members of the cluster. In the previous study, we found that the projection effects cause the boost on the amplitudes of clustering and lensing on large scale compared to the expected amplitudes in the absence of any projection effects. These boosts are caused by preferential selections of filamentary structure aligned to the line of sight due to distance uncertainties in photometric surveys. We model the projection effects with two simple assumptions and develop a novel method to quantify the size of the boost using cluster-galaxy cross-correlation functions. We validate our method using mock cluster catalogues built from cosmological N -body simulations and find that we can obtain unbiased constraints on the boost parameter with our model. We then apply our analysis on the SDSS redMaPPer clusters and find that the size of the boost is roughly 20 per cent for all the richness bins except the cluster sample with the richness bin λ ∈ [30, 40]. This is the first study to constrain the boost parameter independent from cluster cosmology studies and provides a self-consistency test for the projection effects. [ABSTRACT FROM AUTHOR]

The connection between the escape fraction of ionizing radiation (f esc) and the properties of galaxies, such as stellar mass (⁠|$\rm M_{\rm *}$|⁠), age, star-formation rate (SFR), and dust content, are key inputs for reionization models, but many of these relationships remain untested at high redshift. We present an analysis of a sample of 96 |$z$| ∼ 3 galaxies from the Keck Lyman Continuum Spectroscopic Survey (KLCS). These galaxies have both sensitive Keck/LRIS spectroscopic measurements of the Lyman continuum (LyC) region, and multiband photometry that places constraints on stellar population parameters. We construct composite spectra from subsamples binned as a function of galaxy property and quantify the ionizing-photon escape for each composite. We find a significant anti-correlation between f esc and |$\rm M_{\rm *}$|⁠ , consistent with predictions from cosmological zoom-in simulations. We also find significant anti-correlation between f esc and E (B−V), encoding the underlying physics of LyC escape in our sample. We also find no significant correlation between f esc and either stellar age or specific SFR (= SFR/ |$\rm M_{\rm *}$|⁠), challenging interpretations that synchronize recent star formation and favorable conditions for ionizing escape. The galaxy properties now shown to correlate with f esc in the KLCS are Lyα equivalent width, UV Luminosity, |$\rm M_{\rm *}$|⁠ , SFR, and E (B−V), but not age or sSFR. This comprehensive analysis of galaxy properties and LyC escape at high redshift will be used to guide future models and observations of the reionization epoch. [ABSTRACT FROM AUTHOR]

We present initial results of a survey of host L * galaxies environments in the Local Volume (⁠|$D\lt 10\,$| Mpc) searching for satellite dwarf galaxy candidates using the wide-field Hyper Suprime-Cam imager on the 8 m Subaru Telescope. This paper presents complete results on NGC2683 (⁠|$M_{B_T,0}=-19.62$|⁠ , |$D=9.36\, \mathrm{ Mpc}$|⁠ , |$v_{\odot }=411\, \mathrm{ km\, s}^{-1}$|⁠), an isolated Sc spiral galaxy in the Leo Spur. At the distance of NGC2683, we image the complete volume out to projected radii of |$380\, \mathrm{ kpc}$| using a hexagonal arrangement of 7 pointings. Direct inspection of the images is complete down to Mg ∼ −11 and has revealed four new satellite galaxy candidates, two of which have been independently discovered by other researchers. Assuming the distance of NGC2683, these candidates span luminosities −12 < Mg < −9 and effective radii 150 pc < re < 1100 pc and are found to be morphologically reminiscent of satellite galaxies in the Local Group. These four new candidates add to the eight already known. A principle component analysis of the 2D projected distribution of the 12 satellite galaxies of NGC2683 reveals a flattened projected disc of satellites, with axis ratio b / a = 0.23. This flattening in the 2D projected system of satellites is a 1 per cent outlier of simulated isotropic satellite systems but is mostly consistent with satellite distributions of comparable galaxy environments in the IllustrisTNG simulation. This indicates the possible presence of a satellite plane, which will need to be investigated with follow-up observations. [ABSTRACT FROM AUTHOR]

Recent analyses show that ΛCDM-based models optimized to reproduce the clustering of massive galaxies overestimate their gravitational lensing by about 30 per cent, the so-called lensing is low problem. Using a state-of-the-art hydrodynamical simulation, we show that this discrepancy reflects shortcomings in standard galaxy–halo connection models rather than tensions within the ΛCDM paradigm itself. Specifically, this problem results from ignoring a variety of galaxy formation effects, including assembly bias, segregation of satellite galaxies relative to dark matter, and baryonic effects on the matter distribution. All these effects contribute towards overestimating gravitational lensing, and when combined, explain the amplitude and scale dependence of the lensing is low problem. We conclude that simplistic galaxy–halo connection models are inadequate to interpret clustering and lensing simultaneously, and that it is crucial to employ more sophisticated models for the upcoming generation of large-scale surveys. [ABSTRACT FROM AUTHOR]

Type Ia supernovae (SNe Ia) are explosions of white dwarf stars that facilitate exquisite measurements of cosmological expansion history, but improvements in accuracy and precision are hindered by observational biases. Of particular concern is the apparent difference in the corrected brightnesses of SNe Ia in different host galaxy environments. SNe Ia in more massive, passive, older environments appear brighter after having been standardized by their light-curve properties. The luminosity difference commonly takes the form of a step function. Recent works imply that environmental characteristics that trace the age of the stellar population in the vicinity of SNe show the largest steps. Here, we use simulations of SN Ia populations to test the impact of using different tracers and investigate promising new models of the step. We test models with a total-to-selective dust extinction ratio R V that changes between young and old SN Ia host galaxies, as well as an intrinsic luminosity difference between SNe from young and old progenitors. The data are well replicated by a model driven by a galaxy-age varying R V and no intrinsic SN luminosity difference, and we find that specific star formation rate measured locally to the SN is a relatively pure tracer of this galaxy-age difference. We cannot rule out an intrinsic difference causing part of the observed step and show that if luminosity differences are caused by multiple drivers then no single environmental measurement is able to accurately trace them. We encourage the use of multiple tracers in luminosity corrections to negate this issue. [ABSTRACT FROM AUTHOR]

The various Euclid imaging surveys will become a reference for studies of galaxy morphology by delivering imaging over an unprecedented area of 15 000 square degrees with high spatial resolution. In order to understand the capabilities of measuring morphologies from Euclid-detected galaxies and to help implement measurements in the pipeline of the Organisational Unit MER of the Euclid Science Ground Segment, we have conducted the Euclid Morphology Challenge, which we present in two papers. While the companion paper focusses on the analysis of photometry, this paper assesses the accuracy of the parametric galaxy morphology measurements in imaging predicted from within the Euclid Wide Survey. We evaluate the performance of five state-of-the-art surface-brightness-fitting codes, DeepLeGATo, Galapagos-2, Morfometryka, ProFit and SourceXtractor++, on a sample of about 1.5 million simulated galaxies (350 000 above 5σ) resembling reduced observations with the Euclid VIS and NIR instruments. The simulations include analytic Sérsic profiles with one and two components, as well as more realistic galaxies generated with neural networks. We find that, despite some code-specific differences, all methods tend to achieve reliable structural measurements (< 10% scatter on ideal Sérsic simulations) down to an apparent magnitude of about IE = 23 in one component and IE = 21 in two components, which correspond to a signal-to-noise ratio of approximately 1 and 5, respectively. We also show that when tested on non-analytic profiles, the results are typically degraded by a factor of 3, driven by systematics. We conclude that the official Euclid Data Releases will deliver robust structural parameters for at least 400 million galaxies in the Euclid Wide Survey by the end of the mission. We find that a key factor for explaining the different behaviour of the codes at the faint end is the set of adopted priors for the various structural parameters. [ABSTRACT FROM AUTHOR]

Fast radio bursts (FRBs) are millisecond-duration transients with large dispersion measures. The origin of FRBs is still mysterious. One of the methods to comprehend FRB origin is to probe the physical environments of FRB host galaxies. Mapping molecular-gas kinematics in FRB host galaxies is critical because it results in star formation that is likely connected to the birth of FRB progenitors. However, most previous works of FRB host galaxies have focused on its stellar component. Therefore, we, for the first time, report the molecular gas kinematics in the host galaxy of the non-repeating FRB 180924B at z = 0.3216. Two velocity components of the CO (3 − 2) emission line are detected in its host galaxy with the Atacama Large Millimeter/submillimeter Array (ALMA): the peak of one component (−155.40 km s−1) is near the centre of the host galaxy, and another (−7.76 km s−1) is near the FRB position. The CO (3 − 2) spectrum shows asymmetric profiles with A peak = 2.03 ± 0.39, where A peak is the peak flux density ratio between the two velocity components. The CO (3 − 2) velocity map also indicates an asymmetric velocity gradient from −180 to 8 km s−1. These results indicate a disturbed kinetic structure of molecular gas in the host galaxy. Such disturbed kinetic structures are reported for repeating FRB host galaxies using H  i emission lines in previous works. Our finding indicates that non-repeating and repeating FRBs could commonly appear in disturbed kinetic environments, suggesting a possible link between the gas kinematics and FRB progenitors. [ABSTRACT FROM AUTHOR]

One of the main goals of the JWST is to study the first galaxies in the Universe. We present a systematic photometric analysis of very distant galaxies in the first JWST deep field towards the massive lensing cluster SMACS0723. As a result, we report the discovery of two galaxy candidates at z ∼ 16, only 250 million years after the big bang. We also identify two candidates at z ∼ 12 and six candidates at z ∼ 9−11. Our search extended out to z ≲ 21 by combining colour information across seven near-infrared camera and near-infrared imager and slitless spectrograph filters. By modelling the Spectral Energy Distributions (SEDs) with EAZY and BEAGLE , we test the robustness of the photometric redshift estimates. While their intrinsic (unlensed) luminosity is typical of the characteristic luminosity L* at z > 10, our high-redshift galaxies typically show small sizes and their morphologies are consistent with disks in some cases. The highest-redshift candidates have extremely blue ultraviolet-continuum slopes −3 < β < −2.4, young ages ∼10−100 Myr, and stellar masses around log (M ⋆/M⊙) = 8.8 inferred from their spectral energy distribution modelling, which indicate a rapid build-up of their stellar mass. Our search clearly demonstrates the capabilities of JWST to uncover robust photometric candidates up to very high redshifts and peer into the formation epoch of the first galaxies. [ABSTRACT FROM AUTHOR]

We present a detection of correlated clustering between MeerKAT radio intensity maps and galaxies from the WiggleZ Dark Energy Survey. We find a 7.7σ detection of the cross-correlation power spectrum, the amplitude of which is proportional to the product of the |${\rm H}\, {\small I}$| density fraction (⁠|$\Omega _{{\rm H}\, {\small I}}$|⁠), |${\rm H}\, {\small I}$| bias (⁠|$b_{{\rm H}\, {\small I}}$|⁠), and the cross-correlation coefficient (r). We therefore obtain the constraint |$\Omega _{{\rm H}\, {\small I}}b_{{\rm H}\, {\small I}}r\, {=}\, [0.86\, {\pm }\, 0.10\, ({\rm stat})\, {\pm }\, 0.12\, ({\rm sys})]\, {\times }\, 10^{-3}$|⁠ , at an effective scale of |$k_{\rm eff}\ {\sim }\ 0.13\, h\, \text{Mpc}^{-1}$|⁠. The intensity maps were obtained from a pilot survey with the MeerKAT telescope, a 64-dish pathfinder array to the SKA Observatory (SKAO). The data were collected from 10.5 h of observations using MeerKAT 's L -band receivers over six nights covering the 11 h field of WiggleZ, in the frequency range 1015–973 MHz (0.400 |$\, {\lt }\, z\, {\lt }\,$| 0.459 in redshift). This detection is the first practical demonstration of the multidish autocorrelation intensity mapping technique for cosmology. This marks an important milestone in the roadmap for the cosmology science case with the full SKAO. [ABSTRACT FROM AUTHOR]

Cosmological analyses with type Ia supernovae (SNe Ia) often assume a single empirical relation between colour and luminosity (β) and do not account for varying host-galaxy dust properties. However, from studies of dust in large samples of galaxies, it is known that dust attenuation can vary significantly. Here, we take advantage of state-of-the-art modelling of galaxy properties to characterize dust parameters (dust attenuation AV , and a parameter describing the dust law slope RV) for 1100 Dark Energy Survey (DES) SN host galaxies. Utilizing optical and infrared data of the hosts alone, we find three key aspects of host dust that impact SN cosmology: (1) there exists a large range (∼1–6) of host RV ; (2) high-stellar mass hosts have RV on average ∼0.7 lower than that of low-mass hosts; (3) for a subsample of 81 spectroscopically classified SNe there is a significant (>3σ) correlation between the Hubble diagram residuals of red SNe Ia and the host RV that when corrected for reduces scatter by |$\sim 13{{\ \rm per\ cent}}$| and the significance of the 'mass step' to ∼1σ. These represent independent confirmations of recent predictions based on dust that attempted to explain the puzzling 'mass step' and intrinsic scatter (σint) in SN Ia analyses. [ABSTRACT FROM AUTHOR]

We use stacked spectra of the host galaxies of photometrically identified Type Ia supernovae (SNe Ia) from the Dark Energy Survey (DES) to search for correlations between Hubble diagram residuals and the spectral properties of the host galaxies. Utilizing full spectrum fitting techniques on stacked spectra binned by Hubble residual, we find no evidence for trends between Hubble residuals and properties of the host galaxies that rely on spectral absorption features (<1.3σ), such as stellar population age, metallicity, and mass-to-light ratio. However, we find significant trends between the Hubble residuals and the strengths of [O  ii ] (4.4σ) and the Balmer emission lines (3σ). These trends are weaker than the well-known trend between Hubble residuals and host galaxy stellar mass (7.2σ) that is derived from broad-band photometry. After light-curve corrections, we see fainter SNe Ia residing in galaxies with larger line strengths. We also find a trend (3σ) between Hubble residual and the Balmer decrement (a measure of reddening by dust) using H β and H γ. The trend, quantified by correlation coefficients, is slightly more significant in the redder SNe Ia, suggesting that the bluer SNe Ia are relatively unaffected by dust in the interstellar medium of the host and that dust contributes to current Hubble diagram scatter impacting the measurement of cosmological parameters. [ABSTRACT FROM AUTHOR]

We present observational constraints on the galaxy–halo connection, focusing particularly on galaxy assembly bias from a novel combination of counts-in-cylinders statistics, P (N CIC), with the standard measurements of the projected two-point correlation function w p(r p), and number density n gal of galaxies. We measure n gal, w p(r p), and P (N CIC) for volume-limited, luminosity-threshold samples of galaxies selected from SDSS DR7, and use them to constrain halo occupation distribution (HOD) models, including a model in which galaxy occupation depends upon a secondary halo property, namely halo concentration. We detect significant positive central assembly bias for the Mr < −20.0 and Mr < −19.5 samples. Central galaxies preferentially reside within haloes of high concentration at fixed mass. Positive central assembly bias is also favoured in the Mr < −20.5 and Mr < −19.0 samples. We find no evidence of central assembly bias in the Mr < −21.0 sample. We observe only a marginal preference for negative satellite assembly bias in the Mr < −20.0 and Mr < −19.0 samples, and non-zero satellite assembly bias is not indicated in other samples. Our findings underscore the necessity of accounting for galaxy assembly bias when interpreting galaxy survey data, and demonstrate the potential of count statistics in extracting information from the spatial distribution of galaxies, which could be applied to both galaxy–halo connection studies and cosmological analyses. [ABSTRACT FROM AUTHOR]

Standard full-shape clustering analyses in Fourier space rely on a fixed power spectrum template, defined at the fiducial cosmology used to convert redshifts into distances, and compress the cosmological information into the Alcock–Paczynski parameters and the linear growth rate of structure. In this paper, we propose an analysis method that operates directly in the cosmology parameter space and varies the power spectrum template accordingly at each tested point. Predictions for the power spectrum multipoles from the TNS model are computed at different cosmologies in the framework of |$\Lambda \rm {CDM}$|⁠. Applied to the final eBOSS QSO and LRG samples together with the low- z DR12 BOSS galaxy sample, our analysis results in a set of constraints on the cosmological parameters Ωcdm, H 0, σ8, Ωb, and ns. To reduce the number of computed models, we construct an iterative process to sample the likelihood surface, where each iteration consists of a Gaussian process regression. This method is validated with mocks from N -body simulations. From the combined analysis of the (e)BOSS data, we obtain the following constraints: σ8 = 0.877 ± 0.049 and |$\Omega _{\rm m}=0.304^{+0.016}_{-0.010}$| without any external prior. The eBOSS quasar sample alone shows a 3.1σ discrepancy compared to the Planck prediction. [ABSTRACT FROM AUTHOR]

The connection between the escape fraction of ionizing photons (f esc) and star formation rate surface density (ΣSFR) is a key input for reionization models, but remains untested at high redshift. We analyse 35 z ∼ 3 galaxies from the Keck Lyman Continuum Survey (KLCS) covered by deep, rest far-UV spectra of the Lyman continuum (LyC) and high-resolution HST V 606 imaging, enabling estimates of both f esc and rest-UV sizes. Using Sérsic profile fits to HST images and spectral-energy distribution fits to multiband photometry, we measure effective sizes and SFRs for the galaxies in our sample, and separate the sample into two bins of ΣSFR. Based on composite spectra, we estimate 〈 f esc〉 for both ΣSFR subsamples, finding no significant difference in 〈 f esc〉 between the two. To test the representativeness of the KLCS HST sample and robustness of this result, we attempt to recover the well-established correlation between f esc and Lyα equivalent width. This correlation is not significant within the KLCS HST sample, indicating that the sample is insufficient for correlating f esc and galaxy properties such as ΣSFR. We perform stacking simulations using the KLCS parent sample to determine the optimal sample size for robust probes of the f esc-ΣSFR connection to inform future observing programs. For a program with a selection independent of ionizing properties, ≥90 objects are required; for one preferentially observing strongly-leaking LyC sources, ≥58 objects are required. More generally, measuring the connection between f esc and ΣSFR requires a larger, representative sample spanning a wide dynamic range in galaxies properties such as ΣSFR. [ABSTRACT FROM AUTHOR]

Using the weak gravitational lensing data from the Hyper Suprime-Cam Subaru Strategic Program (HSC survey), we study the potential of different stellar mass estimates in tracing halo mass. We consider galaxies with log10(M ⋆/M⊙) > 11.5 at 0.2 < z < 0.5 with carefully measured light profiles, and clusters from the redMaPPer and CAMIRA richness-based algorithms. We devise a method (the 'Top- N test') to evaluate the scatter in the halo mass–observable relation for different tracers, and to inter-compare halo mass proxies in four number density bins using stacked galaxy–galaxy lensing profiles. This test reveals three key findings. Stellar masses based on CModel photometry and aperture luminosity within R <30 kpc are poor proxies of halo mass. In contrast, the stellar mass of the outer envelope is an excellent halo mass proxy. The stellar mass within R  = [50, 100] kpc, M ⋆, [50, 100], has performance comparable to the state-of-the-art richness-based cluster finders at log10 M vir ≳ 14.0 and could be a better halo mass tracer at lower halo masses. Finally, using N -body simulations, we find that the lensing profiles of massive haloes selected by M ⋆, [50, 100] are consistent with the expectation for a sample without projection or mis-centring effects. Richness-selected clusters, on the other hand, display an excess at R ∼ 1 Mpc in their lensing profiles, which may suggest a more significant impact from selection biases. These results suggest that M ⋆-based tracers have distinct advantages in identifying massive haloes, which could open up new avenues for cluster cosmology. The codes and data used in this work can be found here: [ABSTRACT FROM AUTHOR]

We explore the capability of deep learning to classify cosmic structures. In cosmological simulations, cosmic volumes are segmented into voids, sheets, filaments, and knots, according to distribution and kinematics of dark matter (DM), and galaxies are also classified according to the segmentation. However, observational studies cannot adopt this classification method using DM. In this study, we demonstrate that deep learning can bridge the gap between the simulations and observations. Our models are based on 3D convolutional neural networks and trained with data of distribution of galaxies in a simulation to deduce the structure classes from the galaxies rather than DM. Our model can predict the class labels as accurate as a previous study using DM distribution for the training and prediction. This means that galaxy distribution can be a substitution for DM for the cosmic-structure classification, and our models using galaxies can be directly applied to wide-field survey observations. When observational restrictions are ignored, our model can classify simulated galaxies into the four classes with an accuracy (macro-averaged F 1-score) of 64 per cent. If restrictions such as limiting magnitude are considered, our model can classify SDSS galaxies at ∼100 Mpc with an accuracy of 60 per cent. In the binary classification distinguishing void galaxies from the others, our model can achieve an accuracy of 88 per cent. [ABSTRACT FROM AUTHOR]