Search

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]

We propose an improved comprehensive method for determining the Hubble constant (⁠|$H_0$|⁠) using the Tully–Fisher relation. By fitting a peculiar velocity model in conjunction with the Tully–Fisher relation, all available data can be used to derive self-consistent Tully–Fisher parameters. In comparison to previous approaches, our method offers several improvements: it can be readily generalized to different forms of the Tully–Fisher relation and its intrinsic scatter; it uses a peculiar velocity model to predict distances more accurately; it can account for all selection effects; it uses the entire data set to fit the Tully–Fisher relation; and it is fully self-consistent. The Tully–Fisher relation zero-point is calibrated using the subset of galaxies with distances from absolute distance indicators. We demonstrate this method on the Cosmicflows-4 catalogue i -band and |$W1$| -band Tully–Fisher samples and show that the uncertainties from fitting the Tully–Fisher relation amount to only 0.2 km s |$^{-1}$|  Mpc |$^{-1}$|⁠. Using all available absolute distance calibrators, we obtain |$H_0=73.3$|   |$\pm$|  2.1 (stat)  |$\pm$|  3.5 (sys) km s |$^{-1}$|  Mpc |$^{-1}$|⁠ , where the statistical uncertainty is dominated by the small number of galaxies with absolute distance estimates. The substantial systematic uncertainty reflects inconsistencies between various zero-point calibrations of the Cepheid period–luminosity relation, the tip of the red giant branch standard candle, and the Type Ia supernova standard candle. However, given a reliable set of absolute distance calibrators, our method promises enhanced precision in |$H_0$| measurements from large new Tully–Fisher samples such as the WALLABY survey. [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]

We propose an improved comprehensive method for determining the Hubble constant (⁠|$H_0$|⁠) using the Tully–Fisher relation. By fitting a peculiar velocity model in conjunction with the Tully–Fisher relation, all available data can be used to derive self-consistent Tully–Fisher parameters. In comparison to previous approaches, our method offers several improvements: it can be readily generalized to different forms of the Tully–Fisher relation and its intrinsic scatter; it uses a peculiar velocity model to predict distances more accurately; it can account for all selection effects; it uses the entire data set to fit the Tully–Fisher relation; and it is fully self-consistent. The Tully–Fisher relation zero-point is calibrated using the subset of galaxies with distances from absolute distance indicators. We demonstrate this method on the Cosmicflows-4 catalogue i -band and |$W1$| -band Tully–Fisher samples and show that the uncertainties from fitting the Tully–Fisher relation amount to only 0.2 km s |$^{-1}$|  Mpc |$^{-1}$|⁠. Using all available absolute distance calibrators, we obtain |$H_0=73.3$|   |$\pm$|  2.1 (stat)  |$\pm$|  3.5 (sys) km s |$^{-1}$|  Mpc |$^{-1}$|⁠ , where the statistical uncertainty is dominated by the small number of galaxies with absolute distance estimates. The substantial systematic uncertainty reflects inconsistencies between various zero-point calibrations of the Cepheid period–luminosity relation, the tip of the red giant branch standard candle, and the Type Ia supernova standard candle. However, given a reliable set of absolute distance calibrators, our method promises enhanced precision in |$H_0$| measurements from large new Tully–Fisher samples such as the WALLABY survey. [ABSTRACT FROM AUTHOR]

This research aims to determine the nature of the relationships among luminous infrared galaxies (LIRGs) by using different methods of distance measurement (distance modulus "dm" and luminosity distance "dl"). We used data from the following sources: NASA Extragalactic Database (NED) and the HYPERLEDA database, where this data was used to study the nature of the relationships and the extent to which they relate to each other . The program (statistica-win-program) was employed, which helped us know the strength of the association between the variables. The results of the statistical analysis showed that there was a strong correlation between dust mass (Mdust dm & Mdust dl) and luminous infrared (LFIRdm, LIRdm) & (LFIRdl, LIRdl), where the partial correlation coefficient was equal to (R⋍0.7) and the slope was linear. There was also a positive correlation between (LFIRdm, LFIRdl)& (Td) where the partial correlation coefficient was (R⋍0.4) with a linear slope. The relationship between (LIR)& (Td) was a positive relation in the modulus distance case (dm), where its correlation was equal to (R⋍0.4), but in another case (luminosity distance), the relation was very weak, and the correlation was (R⋍0.2). The relationship between total masses (Mi ) & (LFIRdm, dl) in both cases of distance (dm) & (dl) was good, and the partial correlation coefficient was equal to (R⋍0.4) with a linear slope. The relationship between (LIR) & (Mi ) in both cases of distance was also positive, and the partial correlation coefficient was equal to (R⋍0.3). There was an inverse relationship between the ratio fluxes (F100/F60) & (Td), as well as a very tight partial correlation coefficient, which was equal to (R⋍-0.9) with a slope of (-1). [ABSTRACT FROM AUTHOR]

We apply the hierarchical probabilistic spectral energy distribution (SED) model bayesn to analyse a sample of 475 type Ia supernovae (0.015 < z < 0.4) from Foundation, DES3YR and PS1MD to investigate the properties of dust in their host galaxies. We jointly infer the dust law RV population distributions at the SED level in high- and low-mass galaxies simultaneously with dust-independent, intrinsic differences. We find an intrinsic mass step of −0.049 ± 0.016 mag, at a significance of 3.1σ, when allowing for a constant intrinsic, achromatic magnitude offset. We additionally apply a model allowing for time- and wavelength-dependent intrinsic differences between SNe Ia in different mass bins, finding ∼2σ differences in magnitude and colour around peak and 4.5σ differences at later times. These intrinsic differences are inferred simultaneously with a difference in population mean RV of ∼2σ significance, demonstrating that both intrinsic and extrinsic differences may play a role in causing the host galaxy mass step. We also consider a model which allows the mean of the RV distribution to linearly evolve with redshift but find no evidence for any evolution – we infer the gradient of this relation η R  = −0.38 ± 0.70. In addition, we discuss in brief a new, GPU-accelerated python implementation of bayesn suitable for application to large surveys which is publicly available and can be used for future cosmological analyses; this code can be found here: https://github.com/bayesn/bayesn. [ABSTRACT FROM AUTHOR]

We present the first fully simulation-based hierarchical analysis of the light curves of a population of low-redshift type Ia supernovæ (SNæ Ia). Our hardware-accelerated forward model, released in the Python package slicsim , includes stochastic variations of each SN's spectral flux distribution (based on the pre-trained BayeSN model), extinction from dust in the host and in the Milky Way, redshift, and realistic instrumental noise. By utilizing truncated marginal neural ratio estimation (TMNRE), a neural network-enabled simulation-based inference technique, we implicitly marginalize over 4000 latent variables (for a set of ≈100 SNæ Ia) to efficiently infer SN Ia absolute magnitudes and host-galaxy dust properties at the population level while also constraining the parameters of individual objects. Amortization of the inference procedure allows us to obtain coverage guarantees for our results through Bayesian validation and frequentist calibration. Furthermore, we show a detailed comparison to full likelihood-based inference, implemented through Hamiltonian Monte Carlo, on simulated data and then apply TMNRE to the light curves of 86 SNæ Ia from the Carnegie Supernova Project, deriving marginal posteriors in excellent agreement with previous work. Given its ability to accommodate arbitrarily complex extensions to the forward model, e.g. different populations based on host properties, redshift evolution, complicated photometric redshift estimates, selection effects, and non-Ia contamination, without significant modifications to the inference procedure, TMNRE has the potential to become the tool of choice for cosmological parameter inference from future, large SN Ia samples. [ABSTRACT FROM AUTHOR]

It is widely accepted that the width–luminosity relation used to standardize normal Type Ia supernovae (SNe Ia) breaks down in underluminous, 1991bg-like SNe Ia. This breakdown may be due to the choice of parameter used as a stand-in for the width of the SN Ia light curve. Using the colour stretch parameter s BV instead of older parameters resolves this issue. Here, I assemble a sample of 14 nearby 1991bg-like SNe Ia from the literature, all of which have independent host-galaxy distance moduli and little to no reddening. I use Gaussian process regression to fit the light curves of these SNe in U / u, B, V, g, R / r, I / i , and H , and measure their peak absolute magnitudes. I find statistically significant (>5σ confidence level in the optical and >4σ in the near-infrared) correlations between the peak absolute magnitudes of the 1991bg-like SNe Ia and their s BV values in the range 0.2 < s BV < 0.6. These correlations are broadly consistent with fits to s BV < 0.7 SNe Ia with preliminary B - and V -band peak absolute magnitudes from the Carnegie Supernova Project and significantly inconsistent with similar fits to normal and transitional SNe Ia (with 0.7 < s BV < 1.1). The underluminous width–luminosity relation shown here needs to be properly calibrated with a homogeneous sample of 1991bg-like SNe Ia, after which it could be used as a rung on a new cosmological distance ladder. With surface-brightness fluctuations (or another non-Cepheid method) used to calibrate distances to nearby 1991bg-like SNe Ia, such a ladder could produce an independent measurement of the Hubble–Lemaître constant, H 0. [ABSTRACT FROM AUTHOR]

Type Ia supernova (SN Ia) as a standard candle is an ideal tool to measure cosmic distance and expansion history of the Universe. Here, we investigate the SN Ia photometric measurement in the China Space Station Telescope Ultra Deep Field (CSST-UDF) survey, and study the constraint power on the cosmological parameters, such as the equation of state of dark energy. The CSST-UDF survey is expected to cover a 9 deg2 sky area in 2 yr with 250 s × 60 exposures for each band. The magnitude limit can reach i ≃ 26 AB mag for 5σ point source detection with a single exposure. We generate light-curve mock data for SNe Ia and different types of core-collapse SNe (CCSNe). sncosmo is chosen as the framework by utilizing the salt3 model to simulate SN Ia data. After selecting high-quality data and fitting the light curves, we derive the light-curve parameters and identify CCSNe as contamination, resulting in ∼2200 SNe with an |$\sim\!\! 7{{\ \rm per\, cent}}$| CCSN contamination rate. We adopt a calibration method similar to Chauvenet's criterion, and apply it to the distance modulus data to further reduce the contamination. We find that this method is effective and can suppress the contamination fraction to |$\sim\!\! 3.5{{\ \rm per\, cent}}$| with 2012 SNe Ia and 73 CCSNe. In the cosmological fitting stage, we did not distinguish between SNe Ia and CCSNe. We find that the constraint accuracies on ΩM, ΩΛ, and w are about two times better than the current SN surveys, and they could be further improved by a factor of ∼1.4 if including the baryon acoustic oscillation data from the CSST spectroscopic wide-field galaxy survey. [ABSTRACT FROM AUTHOR]

We use rest-frame optical and near-infrared (NIR) observations of 42 Type Ia supernovae (SNe Ia) from the Carnegie Supernova Project at low- z and 37 from the RAISIN (SNIA in the IR) Survey at high- z to investigate correlations between SN Ia host galaxy dust, host mass, and redshift. This is the first time the SN Ia host galaxy dust extinction law at high- z has been estimated using combined optical and rest-frame NIR data (YJ band). We use the BayeSN hierarchical model to leverage the data's wide rest-frame wavelength range (extending to ∼1.0–1.2 μ m for the RAISIN sample at 0.2 ≲ z ≲ 0.6). By contrasting the RAISIN and Carnegie Supernova Project (CSP) data, we constrain the population distributions of the host dust R V parameter for both redshift ranges. We place a limit on the difference in population mean R V between RAISIN and CSP of −1.16 < Δμ(R V) < 1.38 with 95 per cent posterior probability. For RAISIN we estimate μ(R V) = 2.58 ± 0.57, and constrain the population standard deviation to σ(R V) < 0.90 [2.42] at the 68 [95] per cent level. Given that we are only able to constrain the size of the low- to high- z shift in μ(R V) to ≲1.4 – which could still propagate to a substantial bias in the equation-of-state parameter w – these and other recent results motivate continued effort to obtain rest-frame NIR data at low- and high-redshifts (e.g. using the Roman Space Telescope). [ABSTRACT FROM AUTHOR]

We present gausSN , a Bayesian semiparametric Gaussian Process (GP) model for time-delay estimation with resolved systems of gravitationally lensed supernovae (glSNe). gausSN models the underlying light curve non-parametrically using a GP. Without assuming a template light curve for each SN type, gausSN fits for the time delays of all images using data in any number of wavelength filters simultaneously. We also introduce a novel time-varying magnification model to capture the effects of microlensing alongside time-delay estimation. In this analysis, we model the time-varying relative magnification as a sigmoid function, as well as a constant for comparison to existing time-delay estimation approaches. We demonstrate that gausSN provides robust time-delay estimates for simulations of glSNe from the Nancy Grace Roman Space Telescope and the Vera C. Rubin Observatory's Legacy Survey of Space and Time (Rubin-LSST). We find that up to 43.6 per cent of time-delay estimates from Roman and 52.9 per cent from Rubin-LSST have fractional errors of less than 5  per cent. We then apply gausSN to SN Refsdal and find the time delay for the fifth image is consistent with the original analysis, regardless of microlensing treatment. Therefore, gausSN maintains the level of precision and accuracy achieved by existing time-delay extraction methods with fewer assumptions about the underlying shape of the light curve than template-based approaches, while incorporating microlensing into the statistical error budget. gausSN is scalable for time-delay cosmography analyses given current projections of glSNe discovery rates from Rubin-LSST and Roman. [ABSTRACT FROM AUTHOR]

Context. Type II Cepheids (T2Cs) are the less frequently used counterparts of classical or type I Cepheids (CCs) which provide the primary calibration of the distance ladder for measuring the Hubble constant in the local Universe. In the era of the "Hubble tension", T2C variables together with the RR Lyrae stars and the tip of the red giant branch (TRGB) can potentially provide non-CC-dependent calibration of the cosmic distance ladder. Aims. Our goal is to provide an absolute calibration of the period–luminosity, period–luminosity–colour, and period–Wesenheit relations (PL, PLC, and PW, respectively) of T2Cs in the Large Magellanic Cloud (LMC), which traditionally serves as a crucial first anchor of the extragalactic distance ladder. Methods. We exploited time-series photometry in the near-infrared (NIR) Y,  J, and Ks bands for a sample of approximately 320 T2Cs in the Magellanic Clouds (MCs). These observations were acquired during 2009–2018 in the context of the VISTA survey of the Magellanic Clouds system (VMC), an ESO public survey. We supplemented the NIR photometry from the VMC survey with well-sampled optical light curves and accurate pulsation periods from the Optical Gravitational Lensing Experiment (OGLE) IV survey and the Gaia mission. We used the best-quality NIR light curves to generate custom templates for modelling sparsely sampled light curves in YJKs bands. Results. The best-fitting YJKs template light curves were used to derive accurate and precise intensity-averaged mean magnitudes and pulsation amplitudes of 277 and 62 T2Cs in the LMC and SMC, respectively. We used optical and NIR mean magnitudes for different T2C subclasses (BLHer, WVir, and RVTau) to derive PL/PLC/PW relations in multiple bands, which were calibrated with the geometric distance to the LMC as derived from eclipsing binaries and with the Gaia parallaxes. We used our new empirical calibrations of PL and PW relations to obtain distances to 22 T2C-host Galactic globular clusters, which were found to be systematically smaller by ∼0.1 mag and 0.03−0.06 mag than in the literature when the zero points are calibrated with the distance of the LMC or Gaia parallaxes, respectively. Better agreement is found between our distances and those based on RR Lyrae stars in globular clusters, providing strong support for using these population II stars together with the TRGB for future distance scale studies. [ABSTRACT FROM AUTHOR]

Future constraints of cosmological parameters from Type Ia supernovae (SNe Ia) will depend on the use of photometric samples, those samples without spectroscopic measurements of the SNe Ia. There is a growing number of analyses that show that photometric samples can be utilized for precision cosmological studies with minimal systematic uncertainties. To investigate this claim, we perform the first analysis that combines two separate photometric samples, SDSS and Pan-STARRS, without including a low-redshift anchor. We evaluate the consistency of the cosmological parameters from these two samples and find they are consistent with each other to under 1σ. From the combined sample, named Amalgame, we measure Ω M = 0.328 ± 0.024 with SN alone in a flat ΛCDM model, and Ω M = 0.330 ± 0.018 and w = |$-1.016^{+0.055}_{-0.058}$| when combining with a Planck data prior and a flat w CDM model. These results are consistent with constraints from the Pantheon+ analysis of only spectroscopically confirmed SNe Ia, and show that there are no significant impediments to analyses of purely photometric samples of SNe Ia. The data and results are made available at https://github.com/bap37/AmalgameDR. [ABSTRACT FROM AUTHOR]

ABSTRACT: Recent analyses have found intriguing correlations between the colour (c) of type Ia supernovae (SNe Ia) and the size of their ‘mass-step’, the relationship between SN Ia host galaxy stellar mass (Mstellar) and SN Ia Hubble residual, and suggest that the cause of this relationship is dust. Using 675 photometrically classified SNe Ia from the Dark Energy Survey 5-yr sample, we study the differences in Hubble residual for a variety of global host galaxy and local environmental properties for SN Ia subsamples split by their colour. We find a 3σ difference in the mass-step when comparing blue (c < 0) and red (c > 0) SNe. We observe the lowest r.m.s. scatter (∼0.14 mag) in the Hubble residual for blue SNe in low mass/blue environments, suggesting that this is the most homogeneous sample for cosmological analyses. By fitting for c-dependent relationships between Hubble residuals and Mstellar, approximating existing dust models, we remove the mass-step from the data and find tentative ∼2σ residual steps in rest-frame galaxy U − R colour. This indicates that dust modelling based on Mstellar may not fully explain the remaining dispersion in SN Ia luminosity. Instead, accounting for a c-dependent relationship between Hubble residuals and global U − R, results in ≤1σ residual steps in Mstellar and local U − R, suggesting that U − R provides different information about the environment of SNe Ia compared to Mstellar, and motivating the inclusion of galaxy U − R colour in SN Ia distance bias correction.

The SH0ES collaboration Hubble constant determination is in a ∼5σ difference with the Planck value, known as the Hubble tension. The accuracy of the Hubble constant measured with extragalactic Cepheids depends on robust stellar-crowding background estimation. Riess et al. (R20) compared the light-curve amplitudes of extragalactic and MW Cepheids to constrain an unaccounted systematic blending bias, |$\gamma =-0.029\pm 0.037\, \rm {mag}$|⁠ , which cannot explain the required, |$\gamma =0.24\pm 0.05\, \rm {mag}$|⁠ , to resolve the Hubble tension. Further checks by Riess et al. demonstrate that a possible blending is not likely related to the size of the crowding correction. We repeat the R20 analysis, with the following main differences: (1) we limit the extragalactic and MW Cepheids comparison to periods |$P\lesssim 50\, \rm {d}$|⁠ , since the number of MW Cepheids with longer periods is minimal; (2) we use publicly available data to recalibrate amplitude ratios of MW Cepheids in standard passbands; (3) we remeasure the amplitudes of Cepheids in NGC 5584 and NGC 4258 in two Hubble Space Telescope filters (F 555 W and F 350 LP) to improve the empirical constraint on their amplitude ratio A 555/ A 350. We show that the filter transformations introduce an |${\approx }0.04\, \rm {mag}$| uncertainty in determining γ, not included by R20. While our final estimate, |$\gamma =0.013\pm 0.057\, \rm {mag}$|⁠ , is consistent with the value derived by R20 and is consistent with no bias, the error is somewhat larger, and the best-fitting value is shifted by |${\approx }0.04\, \rm {mag}$| and closer to zero. Future observations, especially with JWST , would allow better calibration of γ. [ABSTRACT FROM AUTHOR]

Peculiar motion of galaxies probes the structure growth in the universe. In this study, we employ the galaxy stellar mass-binding energy (massE) relation with only two nuisance parameters to build the largest peculiar-velocity (PV) catalogue to date, consisting of 229 890 ellipticals from the main galaxy sample (MGS) of the Sloan Digital Sky Survey (SDSS). We quantify the distribution of the massE-based distances in individual narrow redshift bins (dz  = 0.005), and then estimate the PV of each galaxy based on its offset from the Gaussian mean of the distribution. As demonstrated with the Uchuu-SDSS mock data, the derived PV and momentum power spectra are insensitive to accurate calibration of the massE relation itself, enabling measurements out to a redshift of 0.2, well beyond the current limit of z  = 0.1 using other galaxy scaling laws. We then measure the momentum power spectrum and demonstrate that it remains almost unchanged if varying significantly the redshift bin size within which the distance is measured, as well as the intercept and slope of the massE relation, respectively. By fitting the spectra using the perturbation theory model with four free parameters, f σ8 is constrained to f σ8 = 0.459 |$^{+0.068}_{-0.069}$|  over Δ z  = 0.02–0.2, 0.416 |$^{+0.074}_{-0.076}$|  over Δ z  = 0.02–0.1, and 0.526 |$^{+0.133}_{-0.148}$|  over Δ z  = 0.1–0.2. The error of f σ8 is 2.1 times smaller than that by the redshift space distortion (RSD) of the same sample. A Fisher matrix forecast illustrates that the constraint on f σ8 from the massE-based PV can potentially exceed that from the stage-IV RSD in late universe (z <0.5). [ABSTRACT FROM AUTHOR]

Strong gravitational lensing provides a natural opportunity to test general relativity (GR). We propose a model-independent method for simultaneous constraining on Hubble constant (H 0) and post-Newtonian parameter (γPPN) using strong lensing systems and observational Type Ia supernovae. The time-delay measurements from strong lensing can directly determine the Hubble constant, and the lens distance inferred from the spectroscopic measurement of the stellar kinematics of the deflector galaxy can help us to constrain the post-Newtonian parameter. We seek the Pantheon data set and reconstruct unanchored distances using Gaussian process regression to achieve the cosmological-model-independent GR testing instead of assuming a specific model, which can reduce possible bias on GR testing and measurement of Hubble constant. Combining the reconstructed unanchored distances and the four H0LiCOW lens data sets, our results are |$H_0=72.9^{+2.0}_{-2.3} \, \mathrm{km \, s^{-1} \, Mpc^{-1}}$| and |$\gamma _{\rm {PPN}}=0.89^{+0.17}_{-0.15}$|⁠. All the lenses show that there is no obvious evidence to support GR deviation within observational uncertainties. In the subsequent analysis, we consider a ratio of distance |${D_{\Delta t}}/{D^{^{\prime }}_{\mathrm{ d}}}$| method to further avoid the influence of H 0 on GR testing. The results show that, except J1206 within the ∼1.2σ observational uncertainty, the remaining three lenses support that GR holds within the 1σ observational uncertainties. [ABSTRACT FROM AUTHOR]

Despite increasingly precise observations and sophisticated theoretical models, the discrepancy between measurements of H 0 from the cosmic microwave background or from baryon acoustic oscillations combined with big bang nucleosynthesis versus those from local distance ladder probes – commonly known as the ' H 0 tension' – continues to perplex the scientific community. To address this tension, early dark energy (EDE) models have been proposed as alternatives to Lambda cold dark matter, as they can change the observed sound horizon and the inferred Hubble constant from measurements based on this. In this paper, we investigate the use of Bayesian model averaging (BMA) to evaluate EDE as a solution to the H 0 tension. BMA consists of assigning a prior to the model and deriving a posterior as for any other unknown parameter in a Bayesian analysis. BMA can be computationally challenging in that one must approximate the joint posterior of both model and parameters. Here, we present a computational strategy for BMA that exploits existing Markov chain Monte Carlo software and combines model-specific posteriors post hoc. In application to a comprehensive analysis of cosmological data sets, we quantify the impact of EDE on the H 0 discrepancy. We find an EDE model probability of |${\sim} 90~{{\ \rm per\ cent}}$| whenever we include the H 0 measurement from Type Ia supernovae in the analysis, whereas the other data show a strong preference for the standard cosmological model. We finally present constraints on common parameters marginalized over both cosmological models. For reasonable priors on models with and without EDE, the H 0 tension is reduced by at least 20 per cent. [ABSTRACT FROM AUTHOR]

In order to investigate the potential Hubble tension, we compile a catalogue of 216 measurements of the Hubble–Lemaître constant H 0 between 2012 and 2022, which includes 109 model-independent measurements and 107 ΛCDM model-based measurements. Statistical analyses of these measurements show that the deviations of the results with respect to the average H 0 are far larger than expected from their error bars if they follow a Gaussian distribution. We find that x σ deviation is indeed equivalent in a Gaussian distribution to x eqσ deviation in the frequency of values, where x eq = 0.72 x 0.88. Hence, a tension of 5σ, estimated between the Cepheid-calibrated type Ia supernovae and cosmic microwave background (CMB) data, is indeed a 3σ tension in equivalent terms of a Gaussian distribution of frequencies. However, this recalibration should be independent of the data whose tension we want to test. If we adopt the previous analysis of data of 1976–2019, the equivalent tension is reduced to 2.25σ. Covariance terms due to correlations of measurements do not significantly change the results. None the less, the separation of the data into two blocks with H 0 < 71 and H 0 ≥ 71 km s−1 Mpc−1 finds compatibility with a Gaussian distribution for each of them without removing any outlier. These statistical results indicate that the underestimation of error bars for H 0 remain prevalent over the past decade, dominated by systematic errors in the methodologies of CMB and local distance ladder analyses. [ABSTRACT FROM AUTHOR]

By searching the Open Supernova Catalog, an extragalactic transient host galaxy database, and literature analyses, I present the largest sample of type Ia supernova (SN Ia) siblings to date. The sample comprises 158 galaxies, consisting of 327 confirmed SNe Ia, over 10 times larger than existing sibling SN Ia samples. SN siblings share host galaxies, and thus share global environmental properties and associated systematic uncertainties. This makes them valuable for both cosmological and astrophysical analyses; for example, sibling SNe Ia allow for comparison of environmental properties within the same galaxy, progenitor comparisons, rates analyses, and multiple calibrations of the Hubble–Lemaître constant. This large sample will provide a variety of new avenues of research, and be of great interest to the wider SN Ia community. To give an example use of this sample, I define a cosmology subsample of 44 siblings; and use it to compare light-curve properties between sibling pairs. I find no evidence for correlations in stretch (x 1) and colour (c) between pairs of siblings. Moreover, by comparing a comparable set of random pairs of SNe Ia through boot-strapping, I find that siblings are no more similar in x 1 and c than any random pair of SNe Ia. Given that siblings share the same hosts, differences in x 1 and c between siblings cannot be due to global galaxy properties. This raises important questions regarding environmental systematics for SN Ia standardization in cosmology, and motivates future analyses of sibling SNe Ia. [ABSTRACT FROM AUTHOR]

Combining cosmological probes has consolidated the standard cosmological model with per cent precision, but some tensions have recently emerged when certain parameters are estimated from the local or primordial Universe. The origin of this behaviour is still under debate; however, it is crucial to study as many probes as possible to cross-check the results with independent methods and provide additional pieces of information to the cosmological puzzle. In this work, by combining several late-Universe probes (0 < z < 10), namely, Type Ia supernovae, baryon acoustic oscillations, cosmic chronometers, and gamma-ray bursts, we aim to derive cosmological constraints independently of local or early-Universe anchors. To test the standard cosmological model and its various extensions, considering an evolving dark energy equation of state and the curvature as a free parameter, we analyse each probe individually and all their possible permutations. Assuming a flat Lambda cold dark matter (ΛCDM) model, the full combination of probes provides |$H_0=67.2^{+3.4}_{-3.2}$| km s−1 Mpc−1 and Ωm = 0.325 ± 0.015 [68 per cent confidence level (C.L.)]. Considering a flat w CDM model, we measure |$w_0=-0.91^{+0.07}_{-0.08}$| (68 per cent C.L.), while by relaxing the flatness assumption (ΛCDM model, 95 per cent C.L.) we obtain |$\Omega _k=0.125^{+0.167}_{-0.165}$|⁠. Finally, we analytically characterize the degeneracy directions and the relative orientation of the probes' contours. By calculating the figure-of-merit, we quantify the synergies among independent methods, estimate the constraining power of each probe, and identify which provides the best contribution to the inference process. Pending the new cosmological surveys, this study confirms the exigency for new emerging probes in the landscape of modern cosmology. [ABSTRACT FROM AUTHOR]

We derive general expressions for how the Alcock–Paczynski distortions affect the power spectrum and the bispectrum of cosmological fields. We compute explicit formulas for the mixing coefficients of bispectrum multipoles in the linear approximation. The leading-order effect for the bispectrum is the uniform dilation of all three wavevectors. The mixing coefficients depend on the shape of the bispectrum triplet. Our results for the bispectrum multipoles are framed in terms of the 'natural' basis of the lengths of three wavevectors but can be easily generalized for other bases and reduction schemes. Our validation tests confirm that the linear approximation is extremely accurate for all power spectrum multipoles. The linear approximation is accurate for the bispectrum monopole but results in sub-per cent level inaccuracies for the bispectrum quadrupole and fails for the bispectrum hexadecapole. Our results can be used to simplify the analysis of the bispectrum from galaxy surveys, especially the measurement of the baryon acoustic oscillation peak position. They can be used to replace numeric schemes with exact analytical formulae. [ABSTRACT FROM AUTHOR]

We have received a new physical characteristics fitting based on actual observational data from the Swift mission's long-duration gamma-ray bursts (LGRBs). We considered such characteristics as the Amati parameters for linear correlation (E iso– E p, i ) and the k -correction for gravitational lensing and Malmquist bias (GLMB) effect. We used the Pantheon SN Ia catalogue and the standard Lambda cold dark matter model with a fixed Hubble constant of H 0 = 70 km s−1 Mpc−1 as the baseline for the Hubble function μ(z). In our paper, we formulated the inverse cosmological calibration problem (ICCP) in the non-parametric statistics framework. The ICCP involves fitting non-observable physical characteristics while assuming a fixed cosmological model. To solve this problem, we developed a new method that is resistant to non-Gaussian processes. This method is based on error propagation through the Monte Carlo method and the Theil–Sen method for linear regression estimate. We have demonstrated the stability and robustness of this assessment method. The parameter estimates are as follows: |$a=0.92^{+0.12}_{-0.12}$|⁠ , |$b=50.32^{+0.33}_{-0.32}$| without considering the GLMB effect, and |$a=0.63^{+0.13}_{-0.14}$|⁠ , |$b=50.12^{+0.33}_{-0.31}$|⁠ , and |$k=1.98^{+0.25}_{-0.24}$| with the effect included. The proposed method can be applied to any other calibration sample of known standard candles, a calibrated sample of LGRBs, and the Hubble function μ(z). In the future, the ICCP idea can be used as an alternative cosmological test for estimating cosmological parameters, including the GLMB effect, or even for the selection of models, providing new information about the Universe. This can be done by analysing the residual values of observational data within the Bayesian statistics paradigm. [ABSTRACT FROM AUTHOR]

We investigate the robustness of baryon acoustic oscillations (BAO) measurements with a photometric galaxy sample using mock galaxy catalogues with various sizes of photometric redshift (photo- z) uncertainties. We first conduct the robustness of BAO measurements, assuming we have a perfect knowledge of photo- z uncertainties. We find that the BAO shift parameter α can be constrained in an unbiased manner even for 3 per cent photometric redshift uncertainties up to z ∼ 1. For instance, α = 1.006 ± 0.078 with 95 per cent confidence level is obtained from 3 per cent photo- z uncertainty data at z  = 1.03 using the sample of M * ≥ 1010.25 M⊙  h −2. We also find that a sparse galaxy sample, e.g. <2 × 10−4 [ h  Mpc−1]3, causes additional noise in the covariance matrix calculation and can bias the constraint on α. Following this, we look into the scenario where incorrect photometric redshift uncertainties are assumed in the fitting model. We find that underestimating the photo- z uncertainty leads to a degradation in the constraining power on α. However, the constrained value of α is not biased. We also quantify the constraining power on Ωm0 assuming the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST)-like covariance and find that the 95 per cent confidence level is σ(Ωm0) ∼ 0.03–0.05 corresponding to the photo- z uncertainties of 1–3 per cent, respectively. Finally, we examine whether the skewness in the photometric redshift can bias the constraint on α and confirm that the constraint on α is unbiased, even assuming a Gaussian photo- z uncertainty in our model. [ABSTRACT FROM AUTHOR]

We investigate the transition scale to homogeneity, R H, using as cosmic tracer the spectroscopic sample of blue galaxies from the Sloan Digital Sky Survey (SDSS). Considering the spatial distribution of the galaxy sample, we compute the two point correlation function ξ(r), the scaled counts in spheres |$\mathcal {N}(\lt r)$|⁠ , and the fractal dimension |$\mathcal {D}_2(r)$| to quantify the homogeneity scale in the Local Universe (0.04 < z < 0.20). The sample in analysis is compared with random and mock catalogues with the same geometry, and the same number of synthetic cosmic objects as the data set, to calculate the covariance matrix for the errors determination. The criteria adopted for the transition-to-homogeneity follows the literature, it is attained when |$\mathcal {D}_2(r)$| reaches the 1 per cent level of the limit value 3 (i.e. where it reaches 2.97) as the scale increases. We obtain R H = 70.33 ± 10.74 Mpc h−1, at the effective redshift z eff = 0.128, for a sample containing |$150\, 302$| SDSS blue galaxies with 0.04 < z < 0.20. Additionally, we perform robustness tests by analysing the homogeneity scale in sub-volumes of the original one, obtaining coherent results; we also check for a possible artefact in our procedure examining a homogeneous synthetic data set as a pseudo-data, verifying that such systematic is absent. Because our analyses concentrate in data at low redshifts, z < 0.20, we find interesting to use cosmography to calculate the radial comoving distances; therefore in this subject our analyses do not use fiducial cosmological model. For completeness, we evaluate the difference of the comoving distances estimation using cosmography and fiducial cosmology. [ABSTRACT FROM AUTHOR]

The co-varying physical couplings (CPC) framework states that physical parameters like the speed of light in vacuum c , the Newtonian constant G , and the cosmological constant Λ could indeed vary with the space–time coordinates x μ. Here, we assume a temporal variation, that is, c (t), G (t), and Λ(t). We show that the McVittie space–time, a black hole in an expanding universe, is a solution of the CPC framework providing naturally an important parameter of the model. Then, we calculate the shadow angular radius of this black hole at cosmological distances. A black hole shadow in the CPC context could be either larger or smaller than the same shadow in the standard cosmology. It depends on how the set { c, G , Λ} varies with time or with the cosmic expansion. [ABSTRACT FROM AUTHOR]

We present the clustering of voids based on the quasar (QSO) sample of the extended Baryon Oscillation Spectroscopic Survey Data Release 16 in configuration space. We define voids as overlapping empty circumspheres computed by Delaunay tetrahedra spanned by quartets of quasars, allowing for an estimate of the depth of underdense regions. To maximize the baryon acoustic oscillation (BAO) signal-to-noise ratio, we consider only voids with radii larger than 36 h −1Mpc. Our analysis shows a negative BAO peak in the cross-correlation of QSOs and voids. The joint BAO measurement of the QSO autocorrelation and the corresponding cross-correlation with voids shows an improvement in 70  per cent of the QSO mocks with an average improvement of |$\sim 5~{{\ \rm per\ cent}}$|⁠. However, on the SDSS data, we find no improvement compatible with cosmic variance. For both mocks and data, adding voids does not introduce any bias. We find under the flat ΛCDM assumption, a distance joint measurement on data at the effective redshift z eff = 1.51 of D V (z eff) = 26.558 ± 0.553. A forecast of a DESI-like survey with 1000 boxes with a similar effective volume recovers the same results as for light-cone mocks with an average of 4.8  per cent improvement in 68  per cent of the boxes. [ABSTRACT FROM AUTHOR]

Much of the research in supernova cosmology is based on an assumption that the peak luminosity of type Ia supernovae (SNe Ia), after a standardization process, is independent of the galactic environment. A series of recent studies suggested that there is a significant correlation between the standardized luminosity and the progenitor age of SNe Ia. The correlation found in the most recent work by Lee et al. [Mon. Not. R. Astron. Soc. 517, 2697 (2022)] is strong enough to explain the extra dimming of distant SNe Ia and therefore casts doubts on the direct evidence of cosmic acceleration. The present work incorporates the uncertainties of progenitor ages, which were ignored in Lee et al., into a fully Bayesian inference framework. We find a weaker dependence of supernova standardized luminosity on the progenitor age, but the detection of correlation remains significant (3.5σ). Assuming that such correlation can be extended to high redshift and applying it to the Pantheon SN Ia data set, we confirm that when the Hubble residual does not include intrinsic scatter, the age-bias could be the primary cause of the observed extra dimming of distant SNe Ia. Furthermore, we use the PAge formalism, which is a good approximation to many dark energy and modified gravity models, to do a model comparison. We find that if intrinsic scatter is included in the Hubble residual, the Lambda cold dark matter model remains a good fit. However, in a scenario without intrinsic scatter, the Lambda cold dark matter model faces a challenge. [ABSTRACT FROM AUTHOR]

The assumption of isotropy – that the Universe looks the same in all directions on large scales – is fundamental to the standard cosmological model. It is therefore critical to empirically test in which regimes this assumption holds. Anisotropies in the cosmic expansion are expected due to non-linear structures in the late Universe. However, the extent to which these anisotropies might impact our low-redshift observations remains to be fully tested. We use general relativistic simulations to determine that the expected anisotropies in the Hubble and deceleration parameters are quadrupolar and dipolar, respectively. We constrain these multipoles simultaneously in the new Pantheon+supernova compilation. In the rest frame of the cosmic microwave background (CMB), including peculiar velocity (PV) corrections, we find an ∼2σ deviation from isotropy. We constrain the eigenvalues of the quadrupole in the Hubble parameter to be λ1 = 0.021 ± 0.011 and λ2 = 0.00 ± 0.012 and place a 1σ upper limit on its amplitude of 2.88 per cent. We find no significant dipole in the deceleration parameter, with amplitude |$q_{\rm dip} = 4.5^{+1.9}_{-5.4}$|⁠. However, in the rest frame of the CMB without PV corrections, we find a >2σ positive amplitude with |$q_{ \rm dip} = 9.6^{+4.0}_{-6.9}$|⁠. Incorporating these anisotropies, the monopole of the Hubble parameter shifts by only 0.30 km s−1 Mpc−1 with respect to the isotropic constraints. [ABSTRACT FROM AUTHOR]

The Linear Point (LP), defined as the mid-point between the baryon acoustic oscillation (BAO) peak and the associated left dip of the two-point correlation function (2PCF), ξ(s), is proposed as a new standard ruler which is insensitive to non-linear effects. In this paper, we use a Bayesian sampler to measure the LP and estimate the corresponding statistical uncertainty, and then perform cosmological parameter constraints with LP measurements. Using the Patchy mock catalogues, we find that the measured LPs are consistent with theoretical predictions at 0.6 per cent level. We find constraints with mid-points identified from the rescaled 2PCF (s 2ξ) more robust than those from the traditional LP based on ξ, as the BAO peak is not always prominent when scanning the cosmological parameter space, with the cost of 2–4 per cent increase of statistical uncertainty. This problem can also be solved by an additional data set that provides strong parameter constraints. Measuring LP from the reconstructed data slightly increases the systematic error but significantly reduces the statistical error, resulting in more accurate measurements. The 1 σ confidence interval of distance scale constraints from LP measurements are 20–30 per cent larger than those of the corresponding BAO measurements. For the reconstructed Sloan Digital Sky Survey Data Release 12 data, the constraints on H 0 and Ωm in a flat-Lambda cold dark matter framework with the LP are generally consistent with those from BAO. When combined with Planck cosmic microwave background data, we obtain |$H_0=68.02_{-0.37}^{+0.36}$| |${\rm km}\, {\rm s}^{-1}\, {\rm Mpc}^{-1}$| and |$\Omega _{\rm m}=0.3055_{-0.0048}^{+0.0049}$| with the LP. [ABSTRACT FROM AUTHOR]

The Euclid mission will provide first-of-its-kind coverage in the near-infrared over deep (three fields, ∼10–20 square degrees each) and wide (∼10 000 square degrees) fields. While the survey is not designed to discover transients, the deep fields will have repeated observations over a two-week span, followed by a gap of roughly six months. In this analysis, we explore how useful the deep field observations will be for measuring properties of Type Ia supernovae (SNe Ia). Using simulations that include Euclid 's planned depth, area, and cadence in the deep fields, we calculate that more than 3700 SNe between 0.0 < |$z$| < 1.5 will have at least five Euclid detections around peak with signal-to-noise ratio larger than 3. While on their own, Euclid light curves are not good enough to directly constrain distances, when combined with legacy survey of space and time (LSST) deep field observations, we find that uncertainties on SN distances are reduced by 20–30  per cent for |$z$| < 0.8 and by 40–50  per cent for |$z$| > 0.8. Furthermore, we predict how well additional Euclid mock data can be used to constrain a key systematic in SN Ia studies – the size of the luminosity 'step' found between SNe hosted in high-mass (>1010 M⊙) and low-mass (<1010 M⊙) galaxies. This measurement has unique information in the rest-frame near-infrared (NIR). We predict that if the step is caused by dust, we will be able to measure its reduction in the NIR compared to optical at the 4σ level. We highlight that the LSST and Euclid observing strategies used in this work are still provisional and some level of joint processing is required. Still, these first results are promising, and assuming that Euclid begins observations well before the Nancy Roman Space Telescope (Roman), we expect this data set to be extremely helpful for preparation for Roman itself. [ABSTRACT FROM AUTHOR]

Type Ia supernovae (SNe Ia) in the nearby Hubble flow are excellent distance indicators in cosmology. The Zwicky Transient Facility (ZTF) has observed a large sample of SNe from an untargeted, rolling survey, reaching 20.8, 20.6, and 20.3 mag in g r, and i band, respectively. With an FoV of 47 deg2, ZTF discovered > 3000 SNe Ia in a little over 2.5 yr. Here, we report on the sample of 761 spectroscopically classified SNe Ia from the first year of operations (DR1). The sample has a median redshift $\bar{z} =$ 0.057, nearly a factor of 2 higher than the current low-z sample. Our sample has a total of 934 spectra, of which 632 were obtained with the robotic SEDm on Palomar P60. We assess the potential for precision cosmology for a total of 305 SNe with redshifts from host galaxy spectra. The sample is already comparable in size to the entire combined literature low-z anchor sample. The median first detection is 13.5 d before maximum light, about 10 d earlier than the median in the literature. Furthermore, six SNe from our sample are at DL < 80 Mpc, for which host galaxy distances can be obtained in the JAMES WEBB SPACE TELESCOPE era, such that we have calibrator and Hubble flow SNe observed with the same instrument. In the entire duration of ZTF-I, we have observed nearly 50 SNe for which we can obtain calibrator distances, key for per cent level distance scale measurements.

Type Ia Supernovae (SNe Ia) are standardizable candles that allow us to measure the recent expansion rate of the Universe. Due to uncertainties in progenitor physics, potential astrophysical dependencies may bias cosmological measurements if not properly accounted for. The dependency of the intrinsic luminosity of SNe Ia with their host-galaxy environment is often used to standardize SNe Ia luminosity and is commonly parameterized as a step function. This functional form implicitly assumes two-populations of SNe Ia. In the literature, multiple environmental indicators have been considered, finding different, sometimes incompatible, step function amplitudes. We compare these indicators in the context of a two-populations model, based on their ability to distinguish the two populations. We show that local Hα-based specific star formation rate (lsSFR) and global stellar mass are better tracers than, for instance, host galaxy morphology. We show that tracer accuracy can explain the discrepancy between the observed SNe Ia step amplitudes found in the literature. Using lsSFR or global mass to identify the two populations can explain all other observations, though lsSFR is favoured. As lsSFR is strongly connected to age, our results favour a prompt and delayed population model. In any case, there exists two populations that differ in standardized magnitude by at least 0.121 ± 0.010 mag.

The position of the peak of the matter power spectrum, the so-called turnover scale, is set by the horizon size at the epoch of matter-radiation equality. It can easily be predicted in terms of the physics of the universe in the relativistic era, and so can be used as a standard ruler, independent of other features present in the matter power spectrum, such as baryon acoustic oscillations (BAOs). We use the distribution of quasars measured by the extended Baryon Oscillation Spectroscopic Survey (eBOSS) to determine the turnover scale in a model-independent fashion statistically. We avoid modelling the BAO by down-weighting affected scales in the covariance matrix using the mode deprojection technique. We measure the wavenumber of the peak to be |$k_\mathrm{TO} = \left(17.6^{+1.9}_{-1.8} \right) \times 10^{-3}h/\mathrm{Mpc}$|⁠ , corresponding to a dilation scale of |$D_\mathrm{V}(z_\mathrm{eff} = 1.48) = \left(31.1^{+4.1}_{-3.4}\right)r_\mathrm{H}$|⁠. This is not competitive with current BAO distance measures in terms of determining the expansion history but does provide a useful cross-check. We combine this measurement with low-redshift distance measurements from type-Ia supernova data from Pantheon and BAO data from eBOSS to make a sound-horizon free estimate of the Hubble–Lemaître parameter and find it to be |$H_0=64.8^{+8.4}_{-7.8} \ \mathrm{km/s/Mpc}$| with Pantheon, and |$H_0=63.3^{+8.2}_{-6.9} \ \mathrm{km/s/Mpc}$| with eBOSS BAO. We make predictions for the measurement of the turnover scale by the Dark Energy Spectroscopic Instrument (DESI) survey, the Maunakea Spectroscopic Explorer (MSE), and MegaMapper, which will make more precise and accurate distance determinations. [ABSTRACT FROM AUTHOR]

The local distance ladder estimate of the Hubble constant (H 0) is important in cosmology, given the recent tension with the early universe inference. We estimate H 0 from the Type Ia supernova (SN Ia) distance ladder, inferring SN Ia distances with the hierarchical Bayesian SED model, BayeSN. This method has a notable advantage of being able to continuously model the optical and near-infrared (NIR) SN Ia light curves simultaneously. We use two independent distance indicators, Cepheids or the tip of the red giant branch (TRGB), to calibrate a Hubble-flow sample of 67 SNe Ia with optical and NIR data. We estimate H 0 = 74.82 ± 0.97 (stat) |$\pm \, 0.84$| (sys) km  |${\rm s}^{-1}\, {\rm Mpc}^{-1}$|  when using the calibration with Cepheid distances to 37 host galaxies of 41 SNe Ia, and 70.92 ± 1.14 (stat) |$\pm \, 1.49$| (sys) km  |${\rm s}^{-1}\, {\rm Mpc}^{-1}$|  when using the calibration with TRGB distances to 15 host galaxies of 18 SNe Ia. For both methods, we find a low intrinsic scatter σ int ≲ 0.1 mag. We test various selection criteria and do not find significant shifts in the estimate of H 0. Simultaneous modelling of the optical and NIR yields up to ∼15  per cent reduction in H 0 uncertainty compared to the equivalent optical-only cases. With improvements expected in other rungs of the distance ladder, leveraging joint optical-NIR SN Ia data can be critical to reducing the H 0 error budget. [ABSTRACT FROM AUTHOR]

We use the state-of-the-art data on cosmic chronometers (CCH) and the Pantheon+compilation of supernovae of Type Ia (SNIa) to test the constancy of the SNIa absolute magnitude, M , and the robustness of the cosmological principle (CP) at z ≲ 2 with a model-agnostic approach. We do so by reconstructing M (z) and the curvature parameter Ω k (z) using Gaussian Processes. Moreover, we use CCH in combination with data on baryon acoustic oscillations (BAO) from various galaxy surveys (6dFGS, BOSS, eBOSS, WiggleZ, DES Y3) to measure the sound horizon at the baryon-drag epoch, r d, from each BAO data point and check their consistency. Given the precision allowed by the CCH, we find that M (z), Ωk(z), and r d(z) are fully compatible (at |$\lt 68$| per cent C.L.) with constant values. This justifies our final analyses, in which we put constraints on these constant parameters under the validity of the CP, the metric description of gravity and standard physics in the vicinity of the stellar objects, but otherwise in a model-independent way. If we exclude the SNIa contained in the host galaxies employed by SH0ES, our results read |$M=(-19.314^{+0.086}_{-0.108})$|  mag, r d = (142.3 ± 5.3) Mpc, and |$\Omega _k=-0.07^{+0.12}_{-0.15}$|⁠ , with H 0 = (71.5 ± 3.1) km s−1 Mpc−1 (68 per cent C.L.). These values are independent of the main data sets involved in the H 0 tension, namely, the cosmic microwave background and the first two rungs of the cosmic distance ladder. If, instead, we also consider the SNIa in the host galaxies, calibrated with Cepheids, we measure |$M=(-19.252^{+0.024}_{-0.036})$|  mag, |$r_\mathrm{ d}=(141.9^{+5.6}_{-4.9})$| Mpc, |$\Omega _\mathrm{ k}=-0.10^{+0.12}_{-0.15}$|⁠ , and |$H_0=(74.0^{+0.9}_{-1.0})$|  km s−1 Mpc−1. [ABSTRACT FROM AUTHOR]

The three-dimensional distribution of the Ly  α forest has been extensively used to constrain cosmology through measurements of the baryon acoustic oscillations (BAO) scale. However, more cosmological information could be extracted from the full shapes of the Ly  α forest correlations through the Alcock–Paczyński (AP) effect. In this work, we prepare for a cosmological analysis of the full shape of the Ly  α forest correlations by studying synthetic data of the extended Baryon Oscillation Spectroscopic Survey (eBOSS). We use a set of 100 eBOSS synthetic data sets in order to validate such an analysis. These mocks undergo the same analysis process as the real data. We perform a full-shape analysis on the mean of the correlation functions measured from the 100 eBOSS realizations, and find that our model of the Ly  α correlations performs well on current data sets. We show that we are able to obtain an unbiased full-shape measurement of D M/ D H(z eff), where D M is the transverse comoving distance, D H is the Hubble distance, and z eff is the effective redshift of the measurement. We test the fit over a range of scales, and decide to use a minimum separation of r min = 25 h −1Mpc. We also study and discuss the impact of the main contaminants affecting Ly  α forest correlations, and give recommendations on how to perform such analysis with real data. While the final eBOSS Ly  α BAO analysis measured D M/ D H(z eff = 2.33) with 4  per cent statistical precision, a full-shape fit of the same correlations could provide an |$\sim 2~{{\ \rm per\ cent}}$| measurement. [ABSTRACT FROM AUTHOR]

We use the latest parallaxes measurements from Gaia DR3 to obtain a geometric calibration of the tip of the red giant branch (TRGB) in Cousins I magnitudes as a standard candle for cosmology. We utilize the following surveys: SkyMapper DR3, APASS DR9, ATLAS Refcat2, and Gaia DR3 synthetic photometry to obtain multiple zero-point calibrations of the TRGB magnitude, |$M_{I}^{TRGB}$|⁠. Our sample contains Milky Way halo stars at high galactic latitudes (| b | > 36) where the impact of metallicity, dust, and crowding are minimized. The magnitude of the TRGB is identified using Sobel edge detection, but this approach introduced a systematic offset. To address this issue, we utilized simulations with parsec isochrones and showed how to calibrate and remove this bias. Applying our method within the colour range where the slope of the TRGB is relatively flat for metal-poor halo stars (1.55 < (BP − RP) < 2.25), we find a weighted average |$M_{I}^{TRGB} = -4.042 \pm 0.041$| (stat) ±0.031 (sys) mag. A geometric calibration of the Milky Way TRGB has the benefit of being independent of other distance indicators and will help probe systematics in the local distance ladder, leading to improved measurements of the Hubble constant. [ABSTRACT FROM AUTHOR]

The mergers of supermassive black hole binaries can serve as standard sirens: the gravitational-wave (GW) analogue of standard candles. The upcoming space-borne GW detectors will be able to discover such systems and estimate their luminosity distances precisely. Unfortunately, weak gravitational lensing can induce significant errors in the measured distance of these standard sirens at high redshift, severely limiting their usefulness as precise distance probes. The uncertainty due to weak lensing can be reduced if the lensing magnification of the siren can be estimated independently, a procedure called 'delensing'. With the help of up-to-date numerical simulations, here we investigate how much the weak-lensing errors can be reduced using convergence maps reconstructed from shear measurements. We also evaluate the impact of delensing on cosmological parameter estimation with bright standard sirens. We find that the weak-lensing errors for sirens at z s = 2.9 can be reduced by about a factor of two on average, but to achieve this would require expensive ultra-deep-field observations for every siren. Such an approach is likely to be practical in only limited cases, and the reduction in the weak-lensing error is therefore likely to be insufficient to significantly improve the cosmological parameter estimation. We conclude that performing delensing corrections is unlikely to be worthwhile, in contrast to the more positive expectations presented in previous studies. For delensing to become more practicable and useful in the future will require significant improvements in the resolution/depth of weak-lensing surveys and/or the methods to reconstruct convergence maps from these surveys. [ABSTRACT FROM AUTHOR]

We search for the baryon acoustic oscillations in the projected cross-correlation function binned into transverse comoving radius between the SDSS-IV DR16 eBOSS quasars and a dense photometric sample of galaxies selected from the DESI Legacy Imaging Surveys. We estimate the density of the photometric sample of galaxies in this redshift range to be about 2900 deg−2, which is deeper than the official DESI emission line galaxy selection, and the density of the spectroscopic sample is about 20 deg−2. In order to mitigate the systematics related to the use of different imaging surveys close to the detection limit, we use a neural network approach that accounts for complex dependences between the imaging attributes and the observed galaxy density. We find that we are limited by the depth of the imaging surveys that affects the density and purity of the photometric sample and its overlap in redshift with the quasar sample, which thus affects the performance of the method. When cross-correlating the photometric galaxies with quasars in the range 0.6 ≤ z ≤ 1.2, the cross-correlation function can provide better constraints on the comoving angular distance DM (6 per cent precision) compared to the constraint on the spherically averaged distance DV (9 per cent precision) obtained from the autocorrelation. Although not yet competitive, this technique will benefit from the arrival of deeper photometric data from upcoming surveys that will enable it to go beyond the current limitations we have identified in this work.

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]

Reconstruction is becoming a crucial procedure of galaxy clustering analysis for future spectroscopic redshift surveys to obtain subper cent level measurement of the baryon acoustic oscillation scale. Most reconstruction algorithms rely on an estimation of the displacement field from the observed galaxy distribution. However, the displacement reconstruction degrades near the survey boundary due to incomplete data and the boundary effects extend to ∼100 Mpc/h within the interior of the survey volume. We study the possibility of using radial velocities measured from the cosmic microwave background observation through the kinematic Sunyaev-Zeldovich effect to improve performance near the boundary. We find that the boundary effect can be reduced to ∼30 − 40 Mpc/h with the velocity information from Simons Observatory. This is especially helpful for dense low redshift surveys where the volume is relatively small and a large fraction of total volume is affected by the boundary.

We present improved photometric measurements for the host galaxies of 206 spectroscopically confirmed type Ia supernovae discovered by the Dark Energy Survey Supernova Program (DES-SN) and used in the first DES-SN cosmological analysis. For the DES-SN sample, when considering a 5D (z, x1, c, α, β) bias correction, we find evidence of a Hubble residual 'mass step', where SNe Ia in high-mass galaxies (>1010M☉) are intrinsically more luminous (after correction) than their low-mass counterparts by γ = 0.040 ± 0.019 mag. This value is larger by 0.031 mag than the value found in the first DES-SN cosmological analysis. This difference is due to a combination of updated photometric measurements and improved star formation histories and is not from host-galaxy misidentification. When using a 1D (redshift-only) bias correction the inferred mass step is larger, with γ = 0.066 ± 0.020 mag. The 1D−5D γ difference for DES-SN is 0.026 ± 0.009 mag. We show that this difference is due to a strong correlation between host galaxy stellar mass and the x1 component of the 5D distance-bias correction. Including an intrinsic correlation between the observed properties of SNe Ia, stretch and colour, and stellar mass in simulated SN Ia samples, we show that a 5D fit recovers γ with −9 mmag bias compared to a +2 mmag bias for a 1D fit. This difference can explain part of the discrepancy seen in the data. Improvements in modelling correlations between galaxy properties and SN is necessary to ensure unbiased precision estimates of the dark energy equation of state as we enter the era of LSST.

Aims. We perform a deep survey of planetary nebulae (PNe) in the spiral galaxy NGC 300 to construct its planetary nebula luminosity function (PNLF). We aim to derive the distance using the PNLF and to probe the characteristics of the most luminous PNe. Methods. We analysed 44 fields observed with MUSE at the VLT, covering a total area of ∼11 kpc2. We find [O III]λ5007 sources using the differential emission line filter (DELF) technique. We identified PNe through spectral classification with the aid of the BPT diagram. The PNLF distance was derived using the maximum likelihood estimation technique. For the more luminous PNe, we also measured their extinction using the Balmer decrement. We estimated the luminosity and effective temperature of the central stars of the luminous PNe based on estimates of the excitation class and the assumption of optically thick nebulae. Results. We identify 107 PNe and derive a most-likely distance modulus (m − M) 0 = 26. 48 − 0.26 + 0.11 $ (m-M)_0 = 26.48^{+0.11}_{-0.26} $ ( d = 1. 98 − 0.23 + 0.10 $ d = 1.98^{+0.10}_{-0.23} $ Mpc). We find that the PNe at the PNLF cutoff exhibit relatively low extinction, with some high-extinction cases caused by local dust lanes. We present the lower limit luminosities and effective temperatures of the central stars for some of the brighter PNe. We also identify a few Type I PNe that come from a young population with progenitor masses > 2.5 M⊙ but do not populate the PNLF cutoff. Conclusions. The spatial resolution and spectral information of MUSE allow precise PN classification and photometry. These capabilities also enable us to resolve possible contamination by diffuse gas and dust, improving the accuracy of the PNLF distance to NGC 300. [ABSTRACT FROM AUTHOR]

The cosmological principle asserts that the Universe looks spatially homogeneous and isotropic on sufficiently large scales. Given its fundamental implications, it is important to empirically test its validity. In this paper, we use the Type Ia supernova (SN Ia) magnitude–redshift relation, from both the Pantheon and joint light-curve analysis compilations, to constrain theoretically motivated anisotropies in the Hubble flow. In particular, we constrain the quadrupole in the effective Hubble parameter and the dipole in the effective deceleration parameter. We find no significant quadrupole term regardless of the redshift frame used. Our results are consistent with the theoretical expectation of a quadrupole moment of a few percent at scales of ∼100  h −1 Mpc. We place an upper limit of an |$\sim 10{{\%}}$| quadrupole amplitude relative to the monopole, H 0, at these scales. We find that we can detect an |$\sim 7{{\%}}$| quadrupole at the 5 σ level, for a forecast low- z sample of 1055 SNe Ia. We find the signficance of an exponentially decaying dipole of the deceleration parameter depends on the redshift frame used. In the heliocentric frame, as expected, it is detected at ∼3 σ significance. In the cosmic microwave background (CMB) rest frame, we find a marginal ∼2 σ dipole, however, after applying peculiar velocity (PV) corrections, the dipole is insignificant. Finally, we find the best-fitting frame of rest relative to the supernovae to differ from that of the CMB at ∼2 σ for both compilations, which reduces to <1 σ when including PV covariance. [ABSTRACT FROM AUTHOR]

The Universe is currently undergoing accelerated expansion driven by dark energy. Dark energy's essential nature remains mysterious: one means of revealing it is by measuring the Universe's size at different redshifts. This may be done using the baryon acoustic oscillation (BAO) feature, a standard ruler in the galaxy two-point correlation function (2PCF). In order to measure the distance scale, one dilates and contracts a template for the 2PCF in a fiducial cosmology, using a scaling factor α. The standard method for finding the best-fitting α is to compute the likelihood over a grid of roughly 100 values of it. This approach is slow; in this work, we propose a significantly faster way. Our method writes the 2PCF as a polynomial in α by Taylor-expanding it about α = 1, exploiting that we know the fiducial cosmology sufficiently well that α is within a few per cent of unity. The likelihood resulting from this expansion may then be analytically solved for the best-fitting α. Our method is 48–85× faster than a directly comparable approach in which we numerically minimize α, and ∼12 000× faster than the standard iterative method. Our work will be highly enabling for upcoming large-scale structure redshift surveys such as that by Dark Energy Spectroscopic Instrument. [ABSTRACT FROM AUTHOR]

In this paper, we present our calibrations of the Tully–Fisher relation in the mid-infrared W 1 (3.4  |$\mu$| m) and W 2 (4.6   |$\mu$| m) bands, using large samples of 877 galaxies and 876 galaxies from 31 clusters in the W 1 and W 2 bands, respectively. Using a new, iterative bivariate fitting procedure we performed two corrections, one for the cluster population incompleteness bias and a second morphological type correction. We initially performed calibrations using total absolute magnitudes and H  i line widths W F 50 derived from the H  i global profiles as a measure of rotational velocity. We then used (i) isophotal magnitudes and (ii) average rotational velocities measured along the flat sections of the spatially resolved rotation curves of the galaxies, which were obtained from the empirical conversion between rotational velocity definitions. We determined that the calibrations using total magnitudes and H  i line widths had smaller total scatter around the TF relations in the W1 and W2 bands than those using either isophotal magnitudes or spatially resolved rotational velocities. These calibrations are M Tot,W1 = (1.77 ± 0.40) − (9.99 ± 0.16)log10(W F 50) and M Tot,W2 = (2.03 ± 0.40) − (10.12 ± 0.16)log10(W F 50), with associated total scatters of σ W 1 = 0.66 and σ W 2 = 0.67. We compared these with previous calibrations in the near-infrared J, H , and K bands and the long-wavelength optical I band which used the same two corrections. The differences between calibrations can be explained by considering the different regions and components of spiral galaxies that are traced by the different wavelengths. The codes used for the calibrations of the Tully–Fisher relation are available from https://github.com/RiannaBell/WISE-TF-Calibration. [ABSTRACT FROM AUTHOR]

The tomographic Alcock–Paczynski (AP) method is a promising method that uses the redshift evolution of anisotropic clustering in redshift space to calibrate cosmology. It extends the applicable range of the AP method to substantially nonlinear scales, yielding very tight cosmological constraints. For future stage-IV slitless spectroscopic surveys, non-negligible redshift errors might reduce the advantage of the tomographic AP method by suppressing the resolution of the nonlinear structure along the line of sight. The present work studies how redshift errors propagate to cosmological parameters in tomographic AP analysis. We use a formula σz  = σ (1 + z) α to model the redshift errors, with σ varying from 0.001 to 0.006 and α varying from 0.5 to 1.5. The redshift errors produce a signal of anisotropic clustering that is similar to a strong Finger-of-God effect, which smears out both the AP signal and the contamination caused by redshift-space distortions (RSD). For the target precision of the Chinese Space Station Telescope optical survey (σ ≲ 0.002), the decrement of constraining power on the dark energy equation of state is mild (⁠|$\lesssim 50{{\ \rm per\ cent}}$|⁠), and the suppression of RSD contamination leads to a smaller bias-to-signal ratio. Our results indicate that the tomographic AP method will remain a useful and complementary tool for analyses of future slitless spectroscopic surveys. [ABSTRACT FROM AUTHOR]

Cosmological models and their corresponding parameters are widely debated because of the current discrepancy between the results of the Hubble constant, H 0, obtained by SNe Ia, and the Planck data from the cosmic microwave background radiation. Thus, considering high redshift probes like gamma-ray bursts (GRBs) is a necessary step. However, using GRB correlations between their physical features to infer cosmological parameters is difficult because GRB luminosities span several orders of magnitude. In our work, we use a three-dimensional relation between the peak prompt luminosity, the rest-frame time at the end of the X-ray plateau, and its corresponding luminosity in X-rays: the so-called 3D Dainotti fundamental plane relation. We correct this relation by considering the selection and evolutionary effects with a reliable statistical method, obtaining a lower central value for the intrinsic scatter, σ int = 0.18 ± 0.07 (47.1 per cent) compared to previous results, when we adopt a particular set of GRBs with well-defined morphological features, called the platinum sample. We have used the GRB fundamental plane relation alone with both Gaussian and uniform priors on cosmological parameters and in combination with SNe Ia and BAO measurements to infer cosmological parameters like H 0, the matter density in the universe (ΩM), and the dark energy parameter w for a w CDM model. Our results are consistent with the parameters given by the Lambda cold dark matter model but with the advantage of using cosmological probes detected up to z  = 5, much larger than the one observed for the furthest SNe Ia. [ABSTRACT FROM AUTHOR]

Gravitational time delays provide a powerful one-step measurement of H 0, independent of all other probes. One key ingredient in time-delay cosmography are high-accuracy lens models. Those are currently expensive to obtain, both, in terms of computing and investigator time (105–106 CPU hours and ∼0.5–1 yr, respectively). Major improvements in modelling speed are therefore necessary to exploit the large number of lenses that are forecast to be discovered over the current decade. In order to bypass this roadblock, we develop an automated modelling pipeline and apply it to a sample of 31 lens systems, observed by the Hubble Space Telescope in multiple bands. Our automated pipeline can derive models for 30/31 lenses with few hours of human time and <100 CPU hours of computing time for a typical system. For each lens, we provide measurements of key parameters and predictions of magnification as well as time delays for the multiple images. We characterize the cosmography-readiness of our models using the stability of differences in the Fermat potential (proportional to time delay) with respect to modelling choices. We find that for 10/30 lenses, our models are cosmography or nearly cosmography grade (<3 per cent and 3–5 per cent variations). For 6/30 lenses, the models are close to cosmography grade (5–10 per cent). These results utilize informative priors and will need to be confirmed by further analysis. However, they are also likely to improve by extending the pipeline modelling sequence and options. In conclusion, we show that uniform cosmography grade modelling of large strong lens samples is within reach. [ABSTRACT FROM AUTHOR]