A5036775360- Gamma-ray bursts and supernovae
- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Astrophysics and Cosmic Phenomena
- Fluid Dynamics Simulations and Interactions
- Stellar, planetary, and galactic studies
- Geophysics and Gravity Measurements
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Nuclear physics research studies
- High-pressure geophysics and materials
- Laser-Plasma Interactions and Diagnostics
- Neutrino Physics Research
- Fluid Dynamics and Vibration Analysis
- Astrophysics and Star Formation Studies
- Computational Fluid Dynamics and Aerodynamics
- High-Energy Particle Collisions Research
- Fluid Dynamics and Heat Transfer
- Traffic control and management
- Scientific Research and Discoveries
- Computational Physics and Python Applications
- Radio Astronomy Observations and Technology
- Methane Hydrates and Related Phenomena
- Cosmology and Gravitation Theories
- Astronomical Observations and Instrumentation
Stockholm University
2016-2025
Universität Hamburg
2022-2025
AlbaNova
2015-2024
Constructor University
2005-2015
University of California, Santa Cruz
2012-2015
Nova Southeastern University
2014
National Postdoctoral Association
2010
University of Bremen
2010
Universidad Nacional Autónoma de México
2007
International University
2004-2006
The production site of the neutron-rich heavy elements that are formed by rapid neutron capture (the r-process) is still unknown despite intensive research. Here we show detailed studies a scenario has been proposed earlier Lattimer & Schramm, Symbalisty Eichler et al., and Davies namely merger two stars. results hydrodynamic full network calculations combined in order to investigate relevance this for r-process nucleosynthesis. Sufficient material ejected explain amount nuclei Galaxy...
Abstract We report the discovery and monitoring of near-infrared counterpart (AT2017gfo) a binary neutron-star merger event detected as gravitational wave source by Advanced Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo (GW170817) short gamma-ray burst Fermi Gamma-ray Burst Monitor (GBM) Integral SPI-ACS (GRB 170817A). The evolution transient light is consistent with predictions for behavior “kilonova/macronova” powered radioactive decay massive neutron-rich nuclides...
In this study we explore the nucleosynthesis in dynamic ejecta of compact binary mergers.We are particularly interested question how sensitive resulting abundance patterns to parameters merging system.Therefore, systematically investigate combinations neutron star masses range from 1.0 2.0 M and, for completeness, compare results with those two simulations a black hole merger.The vary by factor five studied systems, but all amounts (within uncertainties merger rates) compatible being major...
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 report an extremely rapid mechanism for magnetic field amplification during the merger of a binary neutron star system. This has implications production short class gamma-ray bursts, which recent observations suggest may originate in such mergers. In detailed magnetohydrodynamic simulations process, fields are amplified by Kelvin-Helmholtz instabilities beyond magnetar strength and therefore represent strongest universe. The occurs shear layer that forms between stars on time scale only 1...
Abstract The Laser Interferometer Space Antenna (LISA) will be a transformative experiment for gravitational wave astronomy, and, as such, it offer unique opportunities to address many key astrophysical questions in completely novel way. synergy with ground-based and space-born instruments the electromagnetic domain, by enabling multi-messenger observations, add further discovery potential of LISA. next decade is crucial prepare community LISA’s first observations. This review outlines...
We present VULCAN/2D multigroup flux-limited-diffusion radiation-hydrodynamics simulations of binary neutron star mergers, using the Shen equation state, covering ≳ 100 ms, and starting from azimuthal-averaged two-dimensional slices obtained three-dimensional smooth-particle-hydrodynamics Rosswog & Price for 1.4 M☉(baryonic) stars with no initial spins, co-rotating or counter-rotating spins. Snapshots are post-processed at 10 ms intervals a multiangle neutrino-transport solver. find...
With the first direct detection of merging black holes in 2015, era gravitational wave (GW) astrophysics began. A complete picture compact object mergers, however, requires an electromagnetic (EM) counterpart. We report ultraviolet (UV) and X-ray observations by Swift Nuclear Spectroscopic Telescope ARray (NuSTAR) EM counterpart binary neutron star merger GW170817. The bright, rapidly fading emission indicates a high mass ($\approx0.03$ solar masses) wind-driven outflow with moderate...
Compact binary mergers are prime sources of gravitational waves (GWs), targeted by current and next generation detectors. The question 'what is the observable electromagnetic (EM) signature a compact merger?' an intriguing one with crucial consequences to quest for GWs. We present large set numerical simulations that focus on EM signals emerge from dynamically ejected subrelativistic material. These outflows produce time-scale day macronovae – short-lived infrared (IR) ultraviolet (UV)...
We follow the longterm evolution of dynamic ejecta neutron star mergers for up to 100 years and over a density range roughly 40 orders magnitude. include nuclear energy input from freshly synthesized, radioactively decaying nuclei in our simulations study its effects on remnant dynamics. Although heating substantially alters evolution, we find that running networks purely hydrodynamic (i.e. without heating) yields actually acceptable nucleosynthesis results. The main effect radioactive is...
We use 3D hydrodynamic simulations of the long-term evolution neutron star merger ejecta to predict light curves electromagnetic transients that are powered by decay freshly produced r-process nuclei. For dynamic launched tidal and interaction, we adopt grey opacities 10 cm$^2$/g, as suggested recent studies. our reference case a 1.3-1.4 $M_\odot$ merger, find broad IR peak 2-4 d after merger. The luminosity is $\approx 2\times 10^{40}$ erg/s for an average orientation, but increased up...
The electromagnetic transients accompanying compact binary mergers ($\gamma$-ray bursts, afterglows and 'macronovae') are crucial to pinpoint the sky location of gravitational wave sources. Macronovae caused by radioactivity from freshly synthesised heavy elements, e.g. dynamic ejecta various types winds. We study macronova signatures using multi-dimensional radiative transfer calculations. employ code SuperNu state-of-the-art LTE opacities for a few representative elements wind dynamical...
The remnant resulting from the merger of two neutron stars produces neutrinos in copious amounts. In this paper we present neutrino emission results obtained via Newtonian, high-resolution simulations coalescence event. These use three-dimensional smoothed particle hydrodynamics together with a nuclear, temperature dependent equation state and multi-flavour leakage scheme. We details our scheme, discuss star compare them to core-collapse supernova case where has been studied for several...
We present a numerical investigation of the tidal disruption white dwarfs by moderately massive black holes, with particular reference to centers dwarf galaxies and globular clusters. Special attention is given fate all masses that approach hole close enough be disrupted severely compressed such an extent explosive nuclear burning can triggered. Consistent modeling gas dynamics together reactions allows for realistic determination energy release. In most favorable cases, release may...
I discuss simulations of the coalescence black hole neutron star binary systems with masses between 14 and 20 \msun. The calculations use a three-dimensional smoothed particle hydrodynamics code, temperature-dependent, nuclear equation state multi-flavor neutrino scheme. General relativistic effects are mimicked using \Pacz-Wiita pseudo-potential gravitational radiation reaction forces. Opposite to previous, purely Newtonian calculations, in none explored cases episodic mass transfer occurs....
We present the results of a systematic numerical study an alternative progenitor scenario to produce type Ia supernova explosions, which is not restricted ignition CO white dwarf near Chandrasekhar mass. In this scenario, shock-triggered thermonuclear explosion ensues from collision two dwarfs. Consistent modeling gas dynamics together with nuclear reactions using both smoothed particle and grid-based hydrodynamics code are performed viability channel. find that synthesis Ni in fact natural...
We present three-dimensional simulations on a new mechanism for the detonation of sub-Chandrasekhar CO white dwarf in dynamically unstable system where secondary is either pure He or He/CO hybrid. For systems accretion stream directly impacts surface primary, final tens orbits can have mass rates that range from $10^{-5}$ to $10^{-3} M_{\odot}$ s$^{-1}$, leading rapid accumulation helium primary. After $\sim 10^{-2}$ $M_{\odot}$ has been accreted, ram pressure hot torus deflect such no...
We systematically explore the evolution of merger two carbon-oxygen (CO) white dwarfs. The dynamical a 0.9 Msun + 0.6 CO dwarf is followed by three-dimensional SPH simulation. use an elaborate prescription in which artificial viscosity essentially absent, unless shock detected, and much larger number particles than earlier calculations. Based on this simulation, we suggest that central region remnant can, once it has reached quasi-static equilibrium, be approximated as differentially...
Comparing observational abundance features with nucleosynthesis predictions of stellar evolution or explosion simulations can scrutinize two aspects: (a) the conditions in astrophysical production site and (b) quality nuclear physics input utilized. We test r-process calculations for dynamical ejecta neutron star merger based on three different mass models: The Finite Range Droplet Model (FRDM), (quenched version the) Extended Thomas Fermi Strutinsky Integral (ETFSI-Q),...
We present the results of a systematic numerical study onset mass transfer in double degenerate binary systems and its impact on subsequent evolution. All investigated belong to regime direct impact, unstable transfer. In all cases, even those considered by conventional stability analysis, we find long-lived phase continuing for as many several dozen orbital periods. This settles recent debate sparked discrepancy between earlier smoothed particle hydrodynamics (SPH) calculations that showed...
We have explored the Eu production in Milky Way by means of a very detailed chemical evolution model. In particular, we assumed that is formed merging neutron star (or star-black hole) binaries as well Type II supernovae. tested effects several important parameters influencing during two stars, such (i) time-scale coalescence, (ii) yields and (iii) range initial masses for progenitors stars. The from supernovae are uncertain, more than those coalescing so possibilities. compared our model...
We present a large parameter study where we investigate the structure of white dwarf (WD) merger remnants after dynamical phase. A wide range WD masses and compositions are explored, also probe effect different initial conditions. investigated degree mixing between WDs, conditions for detonations as well amount gas ejected. find that systems with lower mass ratios have more total angular momentum result is flung out in tidal tail. Nuclear burning can affect Many binaries contain helium-rich...
Abstract We present Hubble Space Telescope ( HST ) and Chandra imaging, combined with Very Large MUSE integral field spectroscopy of the counterpart host galaxy first binary neutron star merger detected via gravitational-wave emission by LIGO Virgo, GW170817. The galaxy, NGC 4993, is an S0 at z = 0.009783. There evidence for large, face-on spiral shells in continuum edge-on features visible nebular lines. This suggests that 4993 has undergone a relatively recent <mml:math...
In the last decade, enormous progress has been achieved in understanding of various facets coalescing double neutron star and black hole binary systems. One hopes that mergers such compact binaries can be routinely detected with advanced versions ground-based gravitational wave detector facilities, maybe as early 2016. From theoretical side, there also mounting evidence could major sources heavy elements these ideas have gained recent observational support from detection an event interpreted...