A5028860839- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Cosmology and Gravitation Theories
- Pulsars and Gravitational Waves Research
- Astro and Planetary Science
- Chemical Synthesis and Characterization
- Inorganic Fluorides and Related Compounds
- Solid-state spectroscopy and crystallography
- Solar and Space Plasma Dynamics
- Atomic and Subatomic Physics Research
- Astrophysical Phenomena and Observations
- Nuclear Physics and Applications
- Medical Imaging Techniques and Applications
- Space Science and Extraterrestrial Life
- Black Holes and Theoretical Physics
- Superconducting Materials and Applications
- History and Developments in Astronomy
- Particle Detector Development and Performance
- Geophysics and Gravity Measurements
- CCD and CMOS Imaging Sensors
- Relativity and Gravitational Theory
- Spectroscopy Techniques in Biomedical and Chemical Research
Stockholm University
2023
Johns Hopkins University
2019-2023
Fraunhofer Chalmers Research Centre for Industrial Mathematics
2023
We report observations from HST of Cepheids in the hosts 42 SNe Ia used to calibrate Hubble constant (H0). These include all suitable last 40 years at z<0.01, measured with >1000 orbits, more than doubling sample whose size limits precision H0. The are calibrated geometrically Gaia EDR3 parallaxes, masers N4258 (here tripling that Cepheid sample), and DEBs LMC. were same WFC3 instrument filters (F555W, F814W, F160W) negate zeropoint errors. present multiple verifications photometry tests...
We present constraints on cosmological parameters from the Pantheon+ analysis of 1701 light curves 1550 distinct Type Ia supernovae (SNe Ia) ranging in redshift $z=0.001$ to 2.26. This work features an increased sample size, span, and improved treatment systematic uncertainties comparison original Pantheon results a factor two improvement constraining power. For Flat$\Lambda$CDM model, we find $\Omega_M=0.334\pm0.018$ SNe alone. Flat$w_0$CDM measure $w_0=-0.90\pm0.14$ alone, H$_0=73.5\pm1.1$...
We report observations from HST of Cepheids in the hosts 42 SNe Ia used to calibrate Hubble constant (H0). These include all suitable last 40 years at z<0.01, measured with >1000 orbits, more than doubling sample whose size limits precision H0. The are calibrated geometrically Gaia EDR3 parallaxes, masers N4258 (here tripling that Cepheid sample), and DEBs LMC. were same WFC3 instrument filters (F555W, F814W, F160W) negate zeropoint errors. present multiple verifications photometry...
Abstract Recent studies suggest spectroscopic differences explain a fraction of the variation in Type Ia supernova (SN Ia) luminosities after light-curve/color standardization. In this work, (i) we empirically characterize variations standardized SN luminosities, and (ii) use spectroscopically inferred parameter, SIP, to improve precision SNe along distance ladder determination Hubble constant ( H 0 ). First, show that Pantheon+ covariance model modestly overestimates uncertainty magnitudes...
Context. Type Ia supernova (SN Ia) cosmology studies will soon be dominated by systematic, uncertainties, rather than statistical ones. Thus, it is crucial to understand the unknown phenomena potentially affecting their luminosity that may remain, such as astrophysical biases. For accurate application in studies, SN magnitudes need standardised; namely, they must corrected for correlation with light-curve width and colour. Aims. Here, we investigate how standardisation procedure used reduce...
A spectral-energy distribution (SED) model for Type Ia supernovae (SNe Ia) is a critical tool measuring precise and accurate distances across large redshift range constraining cosmological parameters. We present an improved framework, SALT3, which has several advantages over current models including the leading SALT2 (SALT2.4). While SALT3 similar philosophy, it differs from by having estimation of uncertainties, better separation color light-curve stretch, publicly available training code....
Abstract Separating the components of redshift due to expansion and peculiar motion in nearby universe ( z < 0.1) is critical for using Type Ia Supernovae (SNe Ia) measure Hubble constant H 0 ) equation-of-state parameter dark energy w ). Here, we study two dominant “motions” contributing velocities: large-scale, coherent-flow (CF) motions small-scale gravitationally associated galaxies deemed be a galaxy group. We use set 584 low- SNe from Pantheon+ sample, evaluate efficacy corrections...
Abstract We use the largest sample to date of spectroscopic supernova (SN) Ia distances and redshifts look for evidence in Hubble diagram large-scale outflows caused by local voids suggested exist at z < 0.15. Our combines data from Pantheon with Foundation survey, most recent release light curves Carnegie Supernova Project, create a 1295 SNe over redshift range 0.01 2.26. make an inhomogeneous isotropic Lemaitre–Tolman–Bondi metric model void SN distance–redshift relation. conclude that...
The three rung distance ladder, which calibrates Type Ia supernovae through stellar distances linked to geometric measurements, provides the highest precision direct measurement of Hubble constant. In light tension, it is important test individual components ladder. For this purpose, we report a constant from 35 extragalactic Cepheid hosts measured by SH0ES team, using their and redshifts at cz < 3300 km /s , instead any, more distant supernovae, measure flow. are calibrated geometrically in...
ABSTRACT For the past decade, SALT2 has been most common model used to fit Type Ia supernova (SN Ia) light curves for dark energy analyses. Recently, SALT3 was released, which upgraded a number of features but not yet measurements energy. Here, we evaluate impact switching from SN cosmology analysis. We train and on an identical training sample 1083 well-calibrated supernovae, ensuring that any differences found come underlying framework. publicly release results this (the SALT ‘surfaces’)....
A large fraction of Type Ia supernova (SN Ia) observations over the next decade will be in near-infrared (NIR), at wavelengths beyond reach current standard light-curve model for SN cosmology, SALT3 ($\sim 2800$--8700$A$ central filter wavelength). To harness this new sample and reduce future standardization systematic uncertainties, we train NIR (SALT3-NIR) up to 2 $\mu$m with open-source model-training software SALTShaker, which can easily accommodate observations. Using simulated data...
We present a measurement of the Hubble constant ( H 0 ) using type Ia supernovae (SNe Ia) in near-infrared (NIR) from recently updated sample SNe nearby galaxies with distances measured via Cepheid period-luminosity relations by SH0ES project. collected public photometry up to 19 calibrator and 57 flow z > 0.01), directly their peak magnitudes J - -band Gaussian processes spline interpolation. Calibrator together Cepheid-based were used estimate average absolute magnitude each band, while...
Type Ia supernovae (SNe Ia) are a key probe in modern cosmology, as they can be used to measure luminosity distances at gigaparsec scales. Models of their light-curves project heterogeneous observed data onto common basis for analysis. The SALT model currently SN cosmology describes SNe having two sources variability, accounted by color parameter c, and "stretch parameter" x1. We extend the include an additional we label x2, investigate cosmological impact unaddressed light-curve...
The Zwicky Transient Facility SN Ia Data Release 2 provides a perfect opportunity to perform thorough search for and subsequent analysis of high-velocity features (HVFs) in the pre-peak regime. source such remains unclear, but potential origins include circumstellar material, as well enhancements abundances or densities intrinsic supernova (SN) ejecta. Therefore, they may provide clues elusive progenitor explosion scenarios Type SNe (SNe Ia). We employed Markov chain Monte Carlo fitting...
We present constraints on cosmological parameters from the Pantheon+ analysis of 1701 light curves 1550 distinct Type Ia supernovae (SNe Ia) ranging in redshift $z=0.001$ to 2.26. This work features an increased sample size, span, and improved treatment systematic uncertainties comparison original Pantheon results a factor two improvement constraining power. For Flat$Λ$CDM model, we find $Ω_M=0.334\pm0.018$ SNe alone. Flat$w_0$CDM measure $w_0=-0.90\pm0.14$ alone, H$_0=73.5\pm1.1$ km...
Abstract The unknown cause of the correlation between Type Ia supernova (SN Ia) Hubble residuals and their host-galaxy masses (the “mass step”) may bias cosmological parameter measurements. To better understand mass step, we develop a SALT3 light-curve model for SN cosmology that uses 296 low-redshift SNe to derive spectral energy distribution–host-galaxy relationship. resulting has larger Ca ii H K, near-infrared triplet, Si equivalent widths in low-mass host galaxies at 2.2–2.7 σ...
Understanding the impact of astrophysical environment on Type Ia supernova (SN Ia) properties is crucial to minimize systematic uncertainties in cosmological analyses based this probe. We investigate dependence SN SALT2.4 light-curve stretch distance from their nearest galaxy cluster study potential effect intracluster medium (ICM) intrinsic Ia. used largest sample date and cross-matched it with existing X-ray, Sunyaev-Zel'dovich, optical catalogs order relation between detected each modeled...
The Zwicky Transient Facility SN Ia Data Release 2 (ZTF DR2) contains more than 3,000 Type supernovae (SNe Ia), providing the largest homogeneous low-redshift sample of SNe Ia. Having at least one spectrum per event, this data collection is ideal for large-scale statistical studies photometric, spectroscopic and host-galaxy properties Ia, particularly rarer `peculiar' sub-classes. In paper we first present method developed to spectroscopically classify in sample, techniques used model their...
Context. Type Ia supernova (SNIa) are excellent probes of local distance and the growing sample sizes SNIa have driven an increased propensity to study associated systematic uncertainties improve standardisation methods in preparation for next generation cosmological surveys into dark energy equation state, w . Aims. We aim probe potential change parameter, c , with redshift host-galaxy supernova. Improving brightness measurements will require relationship between host be accounted for. In...
We present the first homogeneous release of several thousand Type Ia supernovae (SNe Ia), all having spectroscopic classification, and redshifts for half sample. This release, named "DR2", contains 3628 nearby (z < 0.3) SNe discovered, followed classified by Zwicky Transient Facility survey between March 2018 December 2020. Of these, 3000 have good-to-excellent sampling 2667 pass standard cosmology light-curve quality cuts. is thus largest SN to date, increasing an order magnitude number...
Type Ia supernova (SN Ia) cosmology relies on the estimation of light-curve parameters to derive precision distances, which are used infer cosmological such as H 0 , Ω M Λ and w . The empirical SALT2 modeling that only two parameters, a stretch x 1 color c has been by community for almost decades. We study ability model fit nearly 3000 cosmology-grade SN light curves from second release Zwicky Transient Facility (ZTF) science working group. While ZTF data were not train SALT2, algorithm...
Recent studies suggest spectroscopic differences explain a fraction of the variation in Type Ia supernova (SN Ia) luminosities after light-curve/color standardization. In this work, (i) we empirically characterize variations standardized SN luminosities, and (ii) use spectroscopically inferred parameter, SIP, to improve precision SNe along distance ladder determination Hubble constant ($H_0$). First, show that \texttt{Pantheon+} covariance model modestly overestimates uncertainty magnitudes...
We present a measurement of the Hubble constant ($H_0$) using type Ia supernova (SNe Ia) in near-infrared (NIR) from recently updated sample SNe nearby galaxies with distances measured via Cepheid period-luminosity relations by SHOES project. collect public photometry up to 19 calibrator and further 57 flow ($z>0.01$), directly measure their peak magnitudes $J$ $H$ band Gaussian processes spline interpolation. Calibrator together Cepheid-based are used estimate average absolute magnitude...