A5002013850- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Cosmic Phenomena
- Cosmology and Gravitation Theories
- Adaptive optics and wavefront sensing
- Radio Astronomy Observations and Technology
- Pulsars and Gravitational Waves Research
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- CCD and CMOS Imaging Sensors
- Geophysics and Gravity Measurements
- Neutrino Physics Research
- Astrophysics and Star Formation Studies
- Dark Matter and Cosmic Phenomena
- Solar and Space Plasma Dynamics
- Auditing, Earnings Management, Governance
- Stock Market Forecasting Methods
- Financial Markets and Investment Strategies
- Intraperitoneal and Appendiceal Malignancies
- Esophageal Cancer Research and Treatment
- History and Developments in Astronomy
- Calibration and Measurement Techniques
- Infrared Target Detection Methodologies
Lawrence Berkeley National Laboratory
2015-2024
Ludwig-Maximilians-Universität München
2024
Lancaster University
2024
Centre National de la Recherche Scientifique
1999-2024
Austin Peay State University
2024
University of Zurich
2024
American Public University System
2024
Stanford University
2024
Oak Ridge National Laboratory
2024
The Ohio State University Wexner Medical Center
2022-2024
We report measurements of the mass density, ΩM, and cosmological-constant energy ΩΛ, universe based on analysis 42 type Ia supernovae discovered by Supernova Cosmology Project. The magnitude-redshift data for these supernovae, at redshifts between 0.18 0.83, are fitted jointly with a set from Calán/Tololo Survey, below 0.1, to yield values cosmological parameters. All supernova peak magnitudes standardized using SN light-curve width-luminosity relation. measurement yields joint probability...
We present a new compilation of Type Ia supernovae (SNe Ia), dataset low-redshift nearby-Hubble-flow SNe and analysis procedures to work with these heterogeneous compilations. This ``Union'' 414 SN Ia, which reduces 307 after selection cuts, includes the recent large samples from Supernova Legacy Survey ESSENCE Survey, older datasets, as well recently extended distant observed HST. A single, consistent blind procedure is used for all various subsamples, implemented that consistently weights...
We have developed a technique to systematically discover and study high-redshift supernovae that can be used measure the cosmological parameters. report here results based on initial seven of more than 28 discovered date in supernova search Supernova Cosmology Project. find an observational dispersion peak magnitudes σMB=0.27; this narrows σMB, corr=0.19 after "correcting" using light-curve "width-luminosity" relation found for nearby (z ≤ 0.1) Type Ia from Calán/Tololo survey (Hamuy et...
Gaussian processes provide a method for extracting cosmological information from observations without assuming model. We carry out cosmography -- mapping the time evolution of cosmic expansion in model-independent manner using kinematic variables and geometric probe cosmology. Using state art supernova distance data Union2.1 compilation, we constrain, any assumptions about dark energy parametrization or matter density, Hubble parameter deceleration as function redshift. Extraction these...
Previously we used the Nearby Supernova Factory sample to show that Type Ia supernovae (SNe Ia) having locally star-forming environments are dimmer than SNe passive environments. Here use Constitution together with host galaxy data from GALEX independently confirm result. The effect is seen using both SALT2 and MLCS2k2 lightcurve fitting standardization methods, brightness differences of 0.094 ± 0.037 mag for 0.155 0.041 RV = 2.5. When combined our previous measurement 0.025 SALT2. If ratio...
We present an improved measurement of the Hubble constant (H_0) using 'inverse distance ladder' method, which adds information from 207 Type Ia supernovae (SNe Ia) Dark Energy Survey (DES) at redshift 0.018 < z 0.85 to existing measurements 122 low (z 0.07) SNe (Low-z) and Baryon Acoustic Oscillations (BAOs). Whereas traditional H_0 with use a ladder parallax Cepheid variable stars, inverse relies on absolute BAOs calibrate intrinsic magnitude Ia. find = 67.8 +/- 1.3 km s-1 Mpc-1...
We describe the derivation and validation of redshift distribution estimates their uncertainties for populations galaxies used as weak-lensing sources in Dark Energy Survey (DES) Year 1 cosmological analyses. The Bayesian Photometric Redshift (bpz) code is to assign four bins between z ≈ 0.2 ≈1.3, produce initial lensing-weighted distributions |$n^i_{\rm PZ}(z)\propto \mathrm{d}n^i/\mathrm{d}z$| members bin i. Accurate determination parameters depends critically on knowledge ni, but...
We introduce redMaGiC, an automated algorithm for selecting Luminous Red Galaxies (LRGs). The was specifically developed to minimize photometric redshift uncertainties in large-scale structure studies. redMaGiC achieves this by self-training the color-cuts necessary produce a luminosity-thresholded LRG sample of constant comoving density. demonstrate that photozs are very nearly as accurate best machine-learning based methods, yet they require minimal spectroscopic training, do not suffer...
As part of an on-going effort to identify, understand and correct for astrophysics biases in the standardization Type Ia supernovae (SNIa) cosmology, we have statistically classified a large sample nearby SNeIa into those located predominantly younger or older environments. This classification is based on specific star formation rate measured within projected distance 1kpc from each SN location (LsSFR). important refinement compared using local directly as it provides normalization relative...
Abstract We present cosmological constraints from the sample of Type Ia supernovae (SNe Ia) discovered and measured during full 5 yr Dark Energy Survey (DES) SN program. In contrast to most previous samples, in which SNe are classified based on their spectra, we classify DES using a machine learning algorithm applied light curves four photometric bands. Spectroscopic redshifts acquired dedicated follow-up survey host galaxies. After accounting for likelihood each being an Ia, find 1635...
Generative AI tools such as ChatGPT are expected to disrupt numerous industries and could fundamentally alter the way economic agents process information. We probe usefulness of these in extracting information from complex corporate disclosures using stock market a laboratory. use GPT language model summarize textual disclosed by companies their annual reports (MD&A) during conference calls. Unconstrained summaries dramatically shorter compared original disclosures, whereas content is...
We present cosmological constraints from the sample of Type Ia supernovae (SN Ia) discovered during full five years Dark Energy Survey (DES) Supernova Program. In contrast to most previous samples, in which SN are classified based on their spectra, we classify DES SNe using a machine learning algorithm applied light curves four photometric bands. Spectroscopic redshifts acquired dedicated follow-up survey host galaxies. After accounting for likelihood each being Ia, find 1635 redshift range...
Abstract We implement Crossing Statistics to reconstruct in a model-agnostic manner the expansion history of universe and properties dark energy, using DESI Data Release 1 (DR1) BAO data combination with one three different supernova compilations (PantheonPlus, Union3, DES-SN5YR) Planck CMB observations. Our results hint towards an evolving emergent energy behaviour, negligible presence at z ≳ 1, varying significance depending on sets combined. In all these reconstructions, cosmological...
We investigate whether an LLM can successfully perform financial statement analysis in a way similar to professional human analyst. provide standardized and anonymous statements GPT4 instruct the model analyze them determine direction of future earnings. Even without any narrative or industry-specific information, outperforms analysts its ability predict earnings changes. The exhibits relative advantage over situations when tend struggle. Furthermore, we find that prediction accuracy is on...
The measurement of the cosmological parameters from Type Ia supernovae hinges on our ability to compare nearby and distant accurately. Here we present an advance a method for performing generalized K-corrections which allows us these objects UV near-IR over redshift range 0<z<2. We discuss errors currently associated with this how future data can improve upon it significantly. also examine effects reddening light curves supernovae. Finally, provide few examples techniques affect current...
We describe an algorithm for identifying point-source transients and moving objects on reference-subtracted optical images containing artifacts of processing instrumentation. The makes use the supervised machine learning technique known as Random Forest. present results from its in Dark Energy Survey Supernova program (DES-SN), where it was trained using a sample 898,963 signal background events generated by transient detection pipeline. After reprocessing data collected during first DES-SN...
We present the first cosmological parameter constraints using measurements of type Ia supernovae (SNe Ia) from Dark Energy Survey Supernova Program (DES-SN). The analysis uses a subsample 207 spectroscopically confirmed SNe three years DES-SN, combined with low-redshift sample 122 literature. Our "DES-SN3YR" result these 329 is based on series companion analyses and improvements covering SN discovery, spectroscopic selection, photometry, calibration, distance bias corrections, evaluation...
The Large Synoptic Survey Telescope is designed to provide an unprecedented optical imaging dataset that will support investigations of our Solar System, Galaxy and Universe, across half the sky over ten years repeated observation. However, exactly how LSST observations be taken (the observing strategy or "cadence") not yet finalized. In this dynamically-evolving community white paper, we explore detailed performance anticipated science expected depend on small changes strategy. Using...
OzDES is a five-year, 100-night, spectroscopic survey on the Anglo-Australian Telescope, whose primary aim to measure redshifts of approximately 2,500 Type Ia supernovae host galaxies over redshift range 0.1 < z 1.2, and derive reverberation-mapped black hole masses for 500 active galactic nuclei quasars 0.3 4.5. This treasure trove data forms major part follow-up Dark Energy Survey which we are also targeting cluster galaxies, radio strong lenses, unidentified transients, as well measuring...
We describe catalog-level simulations of Type Ia supernova (SN~Ia) light curves in the Dark Energy Survey Supernova Program (DES-SN), and low-redshift samples from Center for Astrophysics (CfA) Carnegie Project (CSP). These are used to model biases selection effects curve analysis, determine bias corrections SN~Ia distance moduli that measure cosmological parameters. To generate realistic curves, simulation uses a detailed model, incorporates information observations (PSF, sky noise, zero...
We present a sample of 21 hydrogen-free superluminous supernovae (SLSNe-I), and one hydrogen-rich SLSN (SLSN-II) detected during the five-year Dark Energy Survey (DES). These SNe, located in redshift range 0.220<z<1.998, represent largest homogeneously-selected events at high redshift. observed g,r, i, z light curves for these which we interpolate using Gaussian Processes. The resulting are analysed to determine luminosity function SLSN-I, their evolutionary timescales. DES SLSN-I...
ABSTRACT We present clustering redshift measurements for Dark Energy Survey (DES) lens sample galaxies used in weak gravitational lensing and galaxy studies. To perform these measurements, we cross-correlate with spectroscopic from the Baryon Acoustic Oscillation (BOSS) its extension, eBOSS. validate our methodology simulations, including a new technique to calibrate systematic errors that result bias, find method is generally unbiased calibrating mean redshift. apply data, estimate...