Abstract
Thick, fully depleted charge-coupled devices are known to exhibit nonlinear behavior at high signal levels due to the dynamic behavior of charges collecting in the potential wells of pixels, ...called the brighter-fatter effect (BFE). The effect results in distorted images of bright calibration stars, creating a flux-dependent point-spread function that if left unmitigated, could make up a large fraction of the error budget in Stage IV weak-lensing (WL) surveys such as the Legacy Survey of Space and Time (LSST). In this paper, we analyze image measurements of flat fields and artificial stars taken at different illumination levels with the LSST Camera (LSSTCam) at SLAC National Accelerator Laboratory in order to quantify this effect in the LSSTCam before and after a previously introduced correction technique. We observe that the BFE evolves anisotropically as a function of flux due to higher-order BFEs, which violates the fundamental assumption of this correction method. We then introduce a new method based on a physically motivated model to account for these higher-order terms in the correction, and then we test the modified correction on both data sets. We find that the new method corrects the effect in flat fields better than it corrects the effect in artificial stars, which we suggest is the result of sub-pixel physics not included in this correction model. We use these results to define a new metric for the full-well capacity of our sensors and advise image processing strategies to further limit the impact of the effect on LSST WL science pathways.
Indonesia's emission reduction commitment and clean energy transition target emphasises the importance of energy system modelling for analysing and projecting Indonesia's capacity, resource ...availability, and future conditions in achieving these objectives. Utilising energy systems modelling based on adequate and reliable data enables policymakers to select the most optimal alternatives in energy planning. Aligned with the U4RIA (Ubuntu, Retrievability, Repeatability, Reconstructability, Interoperability, Auditability) concept, this database may facilitate various related stakeholders in obtaining this comprehensive and detailed energy data, while the data gathering and processing can also be applied to other developing countries. This country-specific dataset covers the historical data of electricity generation, demand, installed capacity, capacity factor, technical lifetime, renewable energy potentials, costs, and its projections up to 2050. The data in this article is ready to be used for energy system and modelling research.
This article introduces an openly accessible dataset aimed at supporting energy system modelling of decarbonisation pathways in the Philippines. The dataset was compiled through an extensive ...literature review, incorporating information from various sources such as the Philippines Department of Energy, academic publications, and international organisations. To ensure compatibility with OSeMOSYS modelling requirements, the data underwent processing and standardisation. It includes power plant data covering existing capacity from classified by grid, off-grid, and planned additions, as well as historical generation data. Additionally, the dataset provides historical and projected electricity demand from 2015 to 2050 segmented by sectors. It also offers technical potential estimates for fossil fuels and renewable energy sources, along with key techno-economic parameters for emerging technologies like floating solar PV, in-stream tidal, and offshore wind. The dataset is freely available on Zenodo, empowering researchers, policymakers, and private-sector actors to conduct independent energy modelling and analyses aligned with the U4RIA framework principles. Its open access encourages collaboration and facilitates informed decision-making to advance a sustainable energy future not only for the Philippines but also for broader global contexts.
Abstract
The largest structures in the cosmic web probe the dynamical nature of dark energy through their integrated Sachs–Wolfe imprints. In the strength of the signal, typical cosmic voids have ...shown good consistency with expectation AISW = ΔTdata/ΔTtheory = 1, given the substantial cosmic variance. Discordantly, large-scale hills in the gravitational potential, or supervoids, have shown excess signals. In this study, we mapped out 87 new supervoids in the total 5000 deg2 footprint of the Dark Energy Survey at 0.2 < $z$ < 0.9 to probe these anomalous claims. We found an excess imprinted profile with AISW ≈ 4.1 ± 2.0 amplitude. The combination with independent BOSS data reveals an ISW imprint of supervoids at the 3.3σ significance level with an enhanced AISW ≈ 5.2 ± 1.6 amplitude. The tension with ΛCDM predictions is equivalent to 2.6σ and remains unexplained.
We report the discovery, spectroscopic confirmation, and first lens models of the first, strongly lensed quasars from a combined search in WISE and Gaia-DR1 over the DES footprint. Their Einstein ...radii span a range between ≈2.0 arcsec and ≈0.4 arcsec. Two of these (WGD2038-4008, RA = 20:38:02.65, Dec. = -40:08:14.64; WGD2021-4115, RA = 20:21:39.45, Dec. = -41:15:57.11) also have confirmed deflector redshifts. The four-image lens WGD2038-4008, with source and deflector redshifts s = 0.777 ± 0.001 and zl = 0.230 ± 0.002, respectively, has a deflector with radius Reff ≈ 3.4 arcsec, stellar mass log(M*/M⊙) = 11.64 + 0.20 -0.43, and extended isophotal shape variation. Simple lens models yield Einstein radii RE = (1.30 ± 0.04) arcsec, axis ratio q = 0.75 ± 0.1 (compatible with that of the starlight) and considerable shear-ellipticity degeneracies. The two-image lens WGD2021-4115 has zs = 1.390 ± 0.001 and zl = 0.335 ± 0.002, and Einstein radius RE = (1.1 ± 0.1) arcsec, but higher-resolution imaging is needed to accurately separate the deflector and faint quasar image. Analogous lens model degeneracies hold for the other six lenses (J0146-1133, J0150-4041, J0235-2433, J0245-0556, J0259-2338, and J0508-2748) shown in this paper.
ABSTRACT
The correlation between the broad line region radius and continuum luminosity (R–L relation) of active galactic nuclei (AGNs) is critical for single-epoch mass estimates of supermassive ...black holes (SMBHs). At z ∼ 1–2, where AGN activity peaks, the R–L relation is constrained by the reverberation mapping (RM) lags of the Mg ii line. We present 25 Mg ii lags from the Australian Dark Energy Survey RM project based on 6 yr of monitoring. We define quantitative criteria to select good lag measurements and verify their reliability with simulations based on both the damped random walk stochastic model and the rescaled, resampled versions of the observed light curves of local, well-measured AGN. Our sample significantly increases the number of Mg ii lags and extends the R–L relation to higher redshifts and luminosities. The relative iron line strength $\mathcal {R}_{\rm Fe}$ has little impact on the R–L relation. The best-fitting Mg iiR–L relation has a slope α = 0.39 ± 0.08 with an intrinsic scatter $\sigma _{\rm rl} = 0.15^{+0.03}_{-0.02}$ . The slope is consistent with previous measurements and shallower than the H β R–L relation. The intrinsic scatter of the new R–L relation is substantially smaller than previous studies and comparable to the intrinsic scatter of the H β R–L relation. Our new R–L relation will enable more precise single-epoch mass estimates and SMBH demographic studies at cosmic noon.
ABSTRACT
Cosmological weak lensing measurements rely on a precise measurement of the shear two-point correlation function (2PCF) along with a deep understanding of systematics that affect it. In this ...work, we demonstrate a general framework for detecting and modelling the impact of PSF systematics on the cosmic shear 2PCF and mitigating its impact on cosmological analysis. Our framework can detect PSF leakage and modelling error from all spin-2 quantities contributed by the PSF second and higher moments, rather than just the second moments, using the cross-correlations between galaxy shapes and PSF moments. We interpret null tests using the HSC Year 3 (Y3) catalogs with this formalism and find that leakage from the spin-2 combination of PSF fourth moments is the leading contributor to additive shear systematics, with total contamination that is an order-of-magnitude higher than that contributed by PSF second moments alone. We conducted a mock cosmic shear analysis for HSC Y3 and find that, if uncorrected, PSF systematics can bias the cosmological parameters Ωm and S8 by ∼0.3σ. The traditional second moment-based model can only correct for a 0.1σ bias, leaving the contamination largely uncorrected. We conclude it is necessary to model both PSF second and fourth moment contaminations for HSC Y3 cosmic shear analysis. We also reanalyse the HSC Y1 cosmic shear analysis with our updated systematics model and identify a 0.07σ bias on Ωm when using the more restricted second moment model from the original analysis. We demonstrate how to self-consistently use the method in both real space and Fourier space, assess shear systematics in tomographic bins, and test for PSF model overfitting.
ABSTRACT
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.
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