A5049962090- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Astronomical Observations and Instrumentation
- Neutrino Physics Research
- Nuclear Physics and Applications
- Solid-state spectroscopy and crystallography
- Astro and Planetary Science
- Spectroscopy and Laser Applications
- Advanced NMR Techniques and Applications
- Galaxies: Formation, Evolution, Phenomena
- Laser Design and Applications
- Crystal Structures and Properties
- Superconducting Materials and Applications
- Calibration and Measurement Techniques
- Spectroscopy Techniques in Biomedical and Chemical Research
- Atomic and Subatomic Physics Research
- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Geophysics and Gravity Measurements
- Laser-Plasma Interactions and Diagnostics
- Chemical and Physical Properties in Aqueous Solutions
Stockholm University
2017-2023
AlbaNova
2017-2023
University of Bonn
2012-2018
Humboldt-Universität zu Berlin
2014-2016
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...
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...
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...
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...
The Public European Southern Observatory Spectroscopic Survey of Transient Objects (PESSTO) began as a public spectroscopic survey in April 2012. We describe the data reduction strategy and products which are publicly available through ESO archive Data Release 1 (SSDR1). PESSTO uses New Technology Telescope with EFOSC2 SOFI to provide optical NIR spectroscopy imaging. target supernovae transients brighter than 20.5mag for classification. Science targets then selected follow-up based on...
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...
We assemble a sample of 24 hydrogen-poor super-luminous supernovae (SLSNe). Parameterizing the light curve shape through rise and decline timescales shows that two are highly correlated. Magnetar-powered models can reproduce correlation, with diversity in rates driven by diffusion timescale. Circumstellar interaction exhibit similar rise-decline relation, but only for narrow range densities, which may be problematic these models. find SLSNe approximately 3.5 magnitudes brighter have curves 3...
We present optical spectra and light curves for three hydrogen-poor superluminous supernovae followed by the Public ESO Spectroscopic Survey of Transient Objects (PESSTO). Time series spectroscopy from a few days after maximum to 100 d later shows them be fairly typical this class, with dominated Ca ii, Mg Fe Si which evolve slowly over most post-peak photospheric phase. determine bolometric apply simple fitting tools, based on diffusion energy input magnetar spin-down, 56Ni decay, collision...
We present an analysis of the early, rising light curves 18 Type Ia supernovae (SNe Ia) discovered by Palomar Transient Factory and La Silla-QUEST variability survey. fit these early data flux using a simple power law (f(t) = α × tn) to determine time first (t0), hence rise (trise) from peak luminosity, exponent power-law (n). find mean uncorrected 18.98 ± 0.54 d, with individual supernova (SN) times ranging 15.98 24.7 d. The n shows significant departures 'fireball model' 2 (or f(t) ∝ t2)...
(Abridged) We study the host galaxy regions in close proximity to Type Ia supernovae (SNe Ia) analyze relations between properties of SN events and environments most similar where their progenitors formed. focus on local H\alpha\ emission as an indicator young environments. The Nearby Supernova Factory has obtained flux-calibrated spectral timeseries for SNe using integral field spectroscopy, allowing simultaneous measurement its immediate vicinity. For 89 we measure tracing ongoing star...
We present data for LSQ14bdq, a hydrogen-poor super-luminous supernova (SLSN) discovered by the La Silla QUEST survey and classified Public ESO Spectroscopic Survey of Transient Objects. The spectrum light curve are very similar to slow-declining SLSNe such as PTF12dam. However, detections within ~1 day after explosion show bright relatively fast initial peak, lasting ~15 days, prior usual slow rise maximum light. broader, main peak can be fit with either central engine or circumstellar...
A key tracer of the elusive progenitor systems Type Ia supernovae (SNe Ia) is detection narrow blueshifted time-varying Na i D absorption lines, interpreted as evidence circumstellar material surrounding system. The origin this controversial, but simplest explanation that it results from previous mass-loss in a system containing white dwarf and non-degenerate companion star. We present new single-epoch intermediate-resolution spectra 17 low-redshift SNe taken with XShooter on European...
The Zwicky Transient Facility is a large optical survey in multiple filters producing hundreds of thousands transient alerts per night. We describe here various machine learning (ML) implementations and plans to make the maximal use data set by taking advantage temporal nature data, further combining it with other sets. start initial steps separating bogus candidates from real ones, stars galaxies, go on classification objects into classes. Besides usual methods (e.g., based features...
The astrophysical r-process site where about half of the elements heavier than iron are produced has been a puzzle for several decades. Here we discuss role neutron star mergers (NSMs) in light first direct detection such an event both gravitational (GW) and electromagnetic (EM) waves. We analyse bolometric NIR lightcurves detected double merger compare them to nuclear reaction network-based macronova models. slope lightcurve is consistent with radioactive decay ejecta $Y_e \lesssim 0.3$...
Early-time observations of Type Ia supernovae (SNe Ia) are essential to constrain their progenitor properties. In this paper, we present high-quality light curves 127 SNe discovered by the Zwicky Transient Facility (ZTF) in 2018. We describe our method perform forced point spread function (PSF) photometry, which can be applied other types extragalactic transients. With a planned cadence six per night ($3g+3r$), all detected both $g$ and $r$ band more than 10\,d (in rest frame) prior epoch...
Both multi-messenger astronomy and new high-throughput wide-field surveys require flexible tools for the selection analysis of astrophysical transients. We here introduce Alert Management, Photometry Evaluation Lightcurves (AMPEL) system, an framework designed suited streamed data. AMPEL combines functionality alert broker with a generic capable hosting user-contributed code, that encourages provenance keeps track varying information states transient displays. The latter concept includes...
The La Silla-QUEST Low Redshift Supernova Survey is a part of the Southern Hemisphere Variability Survey. survey uses 10 deg2 QUEST camera installed at prime focus 1.0-m Schmidt Telescope European Observatory Silla, Chile, and utilizes essentially all observing time telescope. was on ESO telescope in 2009 after completing 5 year variability northern hemisphere using 1.2-m Oschin Palomar. started science operations September. low redshift supernova commenced 2011 December planned to continue...
We study the optical and near-infrared luminosities detectability of radioactively powered electromagnetic transients ('macronovae') occuring in aftermath binary neutron star black hole mergers. explore that result from dynamic ejecta those different types wind outflows. Based on full nuclear network simulations we calculate resulting light curves wavelength bands. scrutinize robustness results by comparing (a) two reaction networks (b) macronova models. particular how sensitive are to...
We describe a dynamic science portal called the GROWTH Marshal that allows time-domain astronomers to define programs; program filters save sources from different discovery streams; coordinate follow-up with various robotic or classical telescopes; analyze panchromatic data; and generate summary tables for publication. The marshal currently serves 137 scientists, 38 programs, 67 telescopes. Every night, in real time, several programs apply customized 105 nightly alerts Zwicky Transient...
Context. Our Local Group of galaxies appears to be moving relative the cosmic microwave background with source peculiar motion still uncertain. While in past this has been studied mostly using as distance indicators, weight type Ia supernovae (SNe Ia) increased recently continuously improving statistics available low-redshift supernovae. Aims. We measured bulk flow nearby universe ($0.015 < z 0.1$) 117 SNe observed by Nearby Supernova Factory, well Union2 compilation SN data already...
We report on our findings based the analysis of observations Type II-L supernova LSQ13cuw within framework currently accepted physical predictions core-collapse explosions. was discovered a day explosion, hitherto unprecedented for supernovae. This motivated comparative study II-P and supernovae with relatively well-constrained explosion epochs rise times to maximum (optical) light. From sample twenty such events, we find evidence positive correlation between duration peak brightness. On...
Type Ia supernova cosmology depends on the ability to fit and standardize observations of magnitudes with an empirical model. We present here a series new models Supernova spectral time that capture greater amount diversity than possible are currently customary. These entitled SuperNova Empirical MOdels (\textsc{SNEMO}\footnote{https://snfactory.lbl.gov/snemo}). The constructed using spectrophotometric from $172$ individual supernovae Nearby Factory, comprising more $2000$ spectra. Using...
When planning a survey for astronomical transients, many factors such as cadence, filter choice, sky coverage, and depth of observations need to be balanced in order optimize the scientific gain survey. Here we present software package called simsurvey simulating supernova lightcurves that are expected based on strategy, which can then used determine potential discoveries each strategy question. The code is set up modular fashion allows easy modification small details enables user adapt it...
ABSTRACT The detection of the binary neutron star (BNS) merger GW170817 and associated electromagnetic (EM) counterpart, ‘kilonova’ (kN) AT2017gfo, opened a new era in multimessenger astronomy. However, despite many efforts, it has been proven very difficult to find additional kNe, even though LIGO/Virgo reported at least one BNS event during their latest run, O3. focus this work is exploration sensitivity adopted optical surveys searching for kNe We propose ways optimize choices filters...