A5021501281- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Pulsars and Gravitational Waves Research
- Galaxies: Formation, Evolution, Phenomena
- Particle physics theoretical and experimental studies
- Astrophysical Phenomena and Observations
- Cosmology and Gravitation Theories
- Quantum Chromodynamics and Particle Interactions
- Neutrino Physics Research
- High-Energy Particle Collisions Research
- Dark Matter and Cosmic Phenomena
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Radio Astronomy Observations and Technology
- Adaptive optics and wavefront sensing
- Particle Detector Development and Performance
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- CCD and CMOS Imaging Sensors
- Astrophysics and Star Formation Studies
- Particle Accelerators and Free-Electron Lasers
- Geophysics and Gravity Measurements
- Solar and Space Plasma Dynamics
Stockholm University
2015-2024
AlbaNova
2015-2024
Max Planck Institute for Radio Astronomy
2014
Max Planck Society
2014
Queen's University Belfast
2007
Indian Institute of Astrophysics
2007
Mount Stromlo Observatory
2007
Australian National University
2007
Université Paris Cité
2007
Laboratoire AstroParticule et Cosmologie
2007
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 distance measurements to 71 high redshift type Ia supernovae discovered during the first year of 5-year Supernova Legacy Survey (SNLS). These events were detected and their multi-color light-curves measured using MegaPrime/MegaCam instrument at Canada-France-Hawaii Telescope (CFHT), by repeatedly imaging four one-square degree fields in bands, as part CFHT (CFHTLS). Follow-up spectroscopy was performed VLT, Gemini Keck telescopes confirm nature measure redshift. With this data...
Aims. We present cosmological constraints from a joint analysis of type Ia supernova (SN Ia) observations obtained by the SDSS-II and SNLS collaborations. The dataset includes several low-redshift samples (z< 0.1), all three seasons (0.05 <z< 0.4), years (0.2 1), it totals 740 spectroscopically confirmed supernovae with high-quality light curves.
We present Advanced Camera for Surveys, NICMOS, and Keck adaptive-optics-assisted photometry of 20 Type Ia supernovae (SNe Ia) from the Hubble Space Telescope (HST) Cluster Supernova Survey. The SNe were discovered over redshift interval 0.623 < z 1.415. Of these Ia, 14 pass our strict selection cuts are used in combination with world's sample to derive best current constraints on dark energy. new 10 beyond = 1, thereby nearly doubling statistical weight HST-discovered this redshift. Our...
We report measurements of ΩM, ΩΛ, and w from 11 supernovae (SNe) at z = 0.36-0.86 with high-quality light curves measured using WFPC2 on the Hubble Space Telescope (HST). This is an independent set high-redshift SNe that confirms previous SN evidence for accelerating universe. The available photometry make it possible these alone to provide cosmological parameters comparable in statistical weight results. Combined earlier Supernova Cosmology Project data, new yield a measurement mass density...
The Zwicky Transient Facility (ZTF) is a new optical time-domain survey that uses the Palomar 48 inch Schmidt telescope. A custom-built wide-field camera provides 47 deg2 field of view and 8 s readout time, yielding more than an order magnitude improvement in speed relative to its predecessor survey, Factory. We describe design implementation observing system. ZTF data system at Infrared Processing Analysis Center near-real-time reduction identify moving varying objects. outline analysis...
We report on work to increase the number of well-measured Type Ia supernovae (SNe Ia) at high redshifts. Light curves, including signal-to-noise Hubble Space Telescope data, and spectra six SNe that were discovered during 2001, are presented. Additionally, for two with z > 1, we present ground-based J-band photometry from Gemini Very Large Telescope. These among most distant which near-IR observations have been obtained. add these together other data sets recently become available in...
The Zwicky Transient Facility (ZTF), a public-private enterprise, is new time domain survey employing dedicated camera on the Palomar 48-inch Schmidt telescope with 47 deg$^2$ field of view and 8 second readout time. It well positioned in development astronomy, offering operations at 10% scale style Large Synoptic Survey Telescope (LSST) single 1-m class telescope. public surveys will cover observable northern sky every three nights g r filters visible Galactic plane night r. Alerts...
Merging neutron stars offer an exquisite laboratory for simultaneously studying strong-field gravity and matter in extreme environments. We establish the physical association of electromagnetic counterpart EM170817 to gravitational waves (GW170817) detected from merging stars. By synthesizing a panchromatic dataset, we demonstrate that are long-sought production site forging heavy elements by r-process nucleosynthesis. The weak gamma-rays seen dissimilar classical short gamma-ray bursts with...
The Sloan Digital Sky Survey-II (SDSS-II) has embarked on a multi-year project to identify and measure light curves for intermediate-redshift (0.05 < z 0.35) Type Ia supernovae (SNe Ia) using repeated five-band (ugriz) imaging over an area of 300 sq. deg. survey region is stripe 2.5° wide centered the celestial equator in Southern Galactic Cap that been imaged numerous times earlier years, enabling construction deep reference image discovery new objects. Supernova observations are being...
We present a novel algorithm for scheduling the observations of time-domain imaging surveys. Our Integer Linear Programming approach optimizes an observing plan entire night by assigning targets to temporal blocks, enabling strict control number exposures obtained per field and minimizing filter changes. A subsequent optimization step minimizes slew times between each observation. metric self-consistently weights contributions from time-varying airmass, seeing, sky brightness maximize...
We explore cosmological constraints on the sum of three active neutrino masses ${M}_{\ensuremath{\nu}}$ in context dynamical dark energy (DDE) models with equation state (EoS) parametrized as a function redshift $z$ by $w(z)={w}_{0}+{w}_{a}z/(1+z)$, and satisfying $w(z)\ensuremath{\ge}\ensuremath{-}1$ for all $z$. make use cosmic microwave background data from Planck satellite, baryon acoustic oscillation measurements, supernovae Ia luminosity distance perform Bayesian analysis. show that,...
Wide-field optical surveys have begun to uncover large samples of fast (trise ≲ 5 d), luminous (Mpeak < −18), blue transients. While commonly attributed the breakout a supernova shock into dense wind, great distances transients this class found so far hampered detailed investigation their properties. We present photometry and spectroscopy from comprehensive worldwide campaign observe AT 2018cow (ATLAS 18qqn), first fast-luminous transient be in real time at low redshift. Our spectra (<2 days...
Abstract We present a public catalog of transients from the Zwicky Transient Facility (ZTF) Bright Survey, magnitude-limited ( m < 19 mag in either g or r filter) survey for extragalactic ZTF stream. introduce cuts on coverage, sky visibility around peak light, and other properties unconnected to nature transient, show that resulting statistical sample is spectroscopically 97% complete at <18 mag, 93% <18.5 75% <19 mag. summarize fundamental this population, identifying distinct...
The discovery of the first electromagnetic counterpart to a gravitational wave signal has generated follow-up observations by over 50 facilities world-wide, ushering in new era multi-messenger astronomy. In this paper, we present event GW170817 and its SSS17a/DLT17ck (IAU label AT2017gfo) 14 Australian telescopes partner observatories as part Australian-based Australian-led research programs. We report early- late-time multi-wavelength observations, including optical imaging spectroscopy,...
Abstract The first James Webb Space Telescope (JWST) Near InfraRed Camera imaging in the field of galaxy cluster PLCK G165.7+67.0 ( z = 0.35) uncovered a Type Ia supernova (SN Ia) at 1.78, called “SN H0pe.” Three different images this one SN were detected as result strong gravitational lensing, each traversing path spacetime, thereby inducing relative delay arrival image. Follow-up JWST observations all three enabled photometric and rare spectroscopic measurements two time delays. Following...
Context. As type Ia supernova cosmology transitions from a statistics-dominated to systematics-dominated era, it is crucial understand the remaining unexplained uncertainties that affect their luminosity, such as those stemming astrophysical biases. Type supernovae are standardisable candles whose absolute magnitude reaches scatter of typically 0.15 mag when empirical correlations with light-curve stretch and colour environmental properties accounted for. Aims. We investigate dependence...
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...
Context. The unprecedented statistics of detected Type Ia supernovae (SNe Ia) brought by the Zwicky Transient Facility (ZTF) enable us to probe impact large-scale structure (LSS) on properties these objects. Aims. goal this paper is explore possible under-dense part LSS intrinsic SALT2 light-curve SNe and uncover biases in SN analyses. Methods. With a volume-limited selection ZTF-Cosmo-DR2 overlapping with SDSS-DR7 survey footprint, we investigated distribution their regard voids galaxy...
R-band intensity measurements along the light curve of Type Ia supernovae (SNe Ia) discovered by Supernova Cosmology Project (SCP) are fitted in brightness to templates allowing a free parameter time-axis width factor w ≡ s(1 + z). The data points then individually aligned time axis, normalized, and K-corrected back rest frame, after which nearly 1300 normalized found lie on well-determined common rest-frame B-band curve, we call "composite curve." same procedure is applied 18 low-redshift...