A5083659319- Gamma-ray bursts and supernovae
- Enzyme Catalysis and Immobilization
- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Microbial Metabolic Engineering and Bioproduction
- Astrophysics and Cosmic Phenomena
- Catalysis for Biomass Conversion
- Metal and Thin Film Mechanics
- Diamond and Carbon-based Materials Research
- Neutrino Physics Research
- Magnetic and Electromagnetic Effects
- Biofuel production and bioconversion
- Lysosomal Storage Disorders Research
- Innovative Microfluidic and Catalytic Techniques Innovation
- Algal biology and biofuel production
- Ultrasound and Hyperthermia Applications
- Plasma Diagnostics and Applications
- Biochemical and Molecular Research
- Particle Accelerators and Free-Electron Lasers
- Ultrasound and Cavitation Phenomena
- Microfluidic and Bio-sensing Technologies
- Electrohydrodynamics and Fluid Dynamics
- Pharmacogenetics and Drug Metabolism
Harvard University
2015-2023
TU Wien
2004-2022
University of Würzburg
2011-2020
Harvard University Press
2017-2020
Max Planck Institute for Astrophysics
2007-2018
European Space Astronomy Centre
2017
Boeing (United States)
2014
Max Planck Society
2007-2012
Heidelberg Institute for Theoretical Studies
2011
Mount Stromlo Observatory
2011
We present results for a suite of 14 three-dimensional, high-resolution hydrodynamical simulations delayed-detonation models Type Ia supernova (SN Ia) explosions. This model comprises the first set three-dimensional SN with detailed isotopic yield information. As such, it may serve as data base Chandrasekhar-mass nucleosynthetic yields and deriving synthetic observables such spectra light curves. employ physically motivated, stochastic based on turbulent velocity fluctuations fuel density to...
The explosion of sub-Chandrasekhar mass white dwarfs via the double detonation scenario is a potential explanation for type Ia supernovae. In this scenario, surface in helium layer initiates underlying carbon/oxygen core leading to an explosion. For given mass, lower bound has been determined on shell required dynamical burning during flash, which necessary prerequisite detonation. range and corresponding minimum masses, we investigate whether assumed capable triggering subsequent even...
Explosions of sub-Chandrasekhar-mass white dwarfs are one alternative to the standard Chandrasekhar-mass model Type Ia supernovae. They interesting since binary systems with primary should be common and this scenario would suggest a simple physical parameter which determines explosion brightness, namely mass exploding dwarf. Here we perform one-dimensional hydrodynamical simulations, associated post-processing nucleosynthesis multi-wavelength radiation transport calculations for pure...
We investigate whether pure deflagration models of Chandrasekhar-mass carbon–oxygen white dwarf stars can account for one or more subclass the observed population Type Ia supernova (SN Ia) explosions. compute a set 3D full-star hydrodynamic explosion models, in which strength is parametrized using multispot ignition approach. For each model, we calculate detailed nucleosynthesis yields post-processing step with 384 nuclide nuclear network. also synthetic observables our Monte Carlo radiative...
Abridged. In the double detonation scenario for Type Ia supernovae (SNe Ia) a initiates in shell of He-rich material accreted from companion star by sub-Chandrasekhar-mass White Dwarf (WD). This drives shock front into carbon-oxygen (C/O) WD that triggers secondary core. The core results complete disruption WD. Earlier studies concluded this has difficulties accounting observed properties SNe since explosion ejecta are surrounded products explosive He burning shell. Recently, it was proposed...
Type Ia supernovae are believed to be white dwarfs disrupted by a thermonuclear explosion. Here we investigate the scenario in which rather low-mass, carbon-oxygen (C + O) dwarf accumulates helium on its surface sufficient amount for igniting detonation shell before Chandrasekhar mass is reached. In principle, this can happen accreting from non-degenerate companion or merging C O with low-mass one. scenario, thought trigger secondary core. It therefore called “double-detonation...
The nearby supernova SN 2011fe can be observed in unprecedented detail. Therefore, it is an important test case for Type Ia (SN Ia) models, which may bring us closer to understanding the physical nature of these objects. Here, we explore how available and expected future observations used constrain explosion scenarios. We base our discussion on three-dimensional simulations a delayed detonation Chandrasekhar-mass white dwarf violent merger two dwarfs-realizations models appropriate most...
We present 32 epochs of optical (3300-9700 \AA) spectrophotometric observations the nearby quintessential "normal" type Ia supernova (SN Ia) SN 2011fe in galaxy M101, extending from -15 to +97 d with respect B-band maximum, obtained by Nearby Supernova Factory collaboration. is closest (\mu = 29.04) and brightest (Bmax 9.94 mag) observed since advent modern large scale programs for intensive periodic followup supernovae. Both synthetic light curve measurements spectral feature analysis...
2002cx-like supernovae are a sub-class of sub-luminous Type Ia (SNe). Their light curves and spectra characterized by distinct features that indicate strong mixing the explosion ejecta. Pure turbulent deflagrations have been shown to produce such mixed Here, we present hydrodynamics, nucleosynthesis radiative-transfer calculations for 3D full-star deflagration Chandrasekhar-mass white dwarf. Our model is able reproduce characteristic observational SN 2005hk (a prototypical supernova), not...
We present theoretical delay times and rates of thermonuclear explosions that are thought to produce Type Ia supernovae, including the double-detonation sub-Chandrasekhar mass model, using population synthesis binary evolution code StarTrack. If detonations carbon-oxygen white dwarfs following a detonation in an accumulated layer helium on dwarf's surface ("double-detonation" models) able which characteristically similar those SNe Ia, then these may account for at least some substantial...
Thermonuclear explosions may arise in binaries which a CO white dwarf (WD) accretes He from companion. If the accretion rate allows sufficiently large mass of to accumulate prior ignition nuclear burning, surface layer detonate, giving rise an astrophysical transient. Detonation generates shock waves that propagate into underlying WD. This might directly ignite detonation at edge WD or compress core trigger near centre. either mechanism works, two detonations can release sufficient energy...
We investigate the brightness distribution expected for thermonuclear explosions that might result from ignition of a detonation during violent merger white dwarf (WD) binaries. Violent WD mergers are subclass canonical double degenerate scenario where two carbon–oxygen (CO) WDs merge when larger fills its Roche lobe. Determining their is critical evaluating whether such an explosion model could be responsible significant fraction observed population Type Ia supernovae (SNe Ia). argue...
Although information is ubiquitous, and its technology arguably among the highest that humankind has produced, very ubiquity posed new types of problems. Three involve storage (rather than computation) include usage energy, robustness stored over long times, ability to resist corruption through tampering. The difficulty in solving these problems using present methods stimulated interest possibilities available fundamentally different strategies, including molecules. Here we show mixtures...
In a companion paper, Seitenzahl et al. have presented set of three-dimensional delayed detonation models for thermonuclear explosions near-Chandrasekhar-mass white dwarfs (WDs). Here, we present multidimensional radiative transfer simulations that provide synthetic light curves and spectra those models. The model sequence explores both changes in the strength deflagration phase (which is controlled by ignition configuration our models) WD central density. agreement with previous studies,...
The gravitationally confined detonation (GCD) model has been proposed as a possible explosion mechanism for Type Ia supernovae in the single-degenerate evolution channel. It starts with ignition of deflagration single off-centre bubble near-Chandrasekhar-mass white dwarf. Driven by buoyancy, flame rises narrow cone towards surface. For most part, main component flow expanding ashes remains radial, but upon reaching outer, low-pressure layers dwarf, an additional lateral develops. This causes...
SN 2010lp is a subluminous Type Ia supernova (SN Ia) with slowly evolving lightcurves. Moreover, it the only observed so far that shows narrow emission lines of [O i] in late-time spectra, indicating unburned oxygen close to center ejecta. Most explosion models for SNe cannot explain emission. Here, we present hydrodynamic and radiative transfer calculations showing violent merger two carbon–oxygen white dwarfs 0.9 0.76 M☉ adequately reproduces early-time observables 2010lp. our model...
We present results based on observations of SN 2015H which belongs to the small group objects similar 2002cx, otherwise known as type Iax supernovae. The availability deep pre-explosion imaging allowed us place tight constraints explosion epoch. Our observational campaign began approximately one day post-explosion, and extended over a period about 150 days post maximum light, making it best observed this class date. find peak magnitude M$_r$ = -17.27 $\pm$ 0.07, ($Δm_{15})_r$ 0.69 0.04....
The rapidly increasing use of digital technologies requires the rethinking methods to store data. This work shows that data can be stored in mixtures fluorescent dye molecules, which are deposited on a surface by inkjet printing, where an amide bond tethers molecules surface. A microscope equipped with multichannel fluorescence detector distinguishes individual dyes mixture. presence or absence these mixture encodes binary information (i.e., "0" "1"). instead sequence-defined macromolecules,...
Nucleosynthetic yield predictions for multidimensional simulations of thermonuclear supernovae generally rely on the tracer particle method to obtain isotopic information ejected material a given supernova simulation. We investigate how many particles are required determine converged integrated total nucleosynthetic yields. For this purpose, we conduct resolution study in number different hydrodynamical explosion models at fixed spatial resolution. perform hydrodynamic co-expanding Eulerian...
We present ultraviolet (UV) spectroscopy and photometry of four Type Ia supernovae (SNe 2004dt, 2004ef, 2005M, 2005cf) obtained with the UV prism Advanced Camera for Surveys on Hubble Space Telescope. This data set provides unique spectral time series down to 2000 Å. Significant diversity is seen in near-maximum-light spectra (∼2000–3500 Å) this small sample. The corresponding photometric data, together archival from Swift Ultraviolet/Optical Telescope observations, provide further evidence...
Smart catalysis cuts it short: Natural (S,S)-Aerangis lactone and its epimer are synthesized with excellent optical purity by using in-line hyphenation of continuous flow reactors batch biotransformations. Optimization the reaction steps engineering reactor interfaces leads to a simple efficient setup, which demonstrates how multistep syntheses can be streamlined into single-operation protocol. As service our authors readers, this journal provides supporting information supplied authors....
Extremely luminous, super-Chandrasekhar (SC) Type Ia Supernovae (SNe Ia) are as yet an unexplained phenomenon. We analyse a well-observed SN of this class, 2009dc, by modelling its photospheric spectra with spectral synthesis code, using the technique 'Abundance Tomography'. present models based on different density profiles, corresponding to explosion scenarios, and discuss their consistency. First, we use structure simulated 2 M_sun rotating C-O white dwarf (WD), which is often proposed...
Calculations of synthetic spectropolarimetry are one means to test multi-dimensional explosion models for Type Ia supernovae. In a recent paper, we demonstrated that the violent merger 1.1 and 0.9 M$_{\odot}$ white dwarf binary system is too asymmetric explain low polarization levels commonly observed in normal Here, present simulations two alternative scenarios: sub-Chandrasekhar mass double-detonation Chandrasekhar delayed-detonation model. Specifically, study two-dimensional model...