Constraining inputs to realistic kilonova simulations through comparison to observed r-process abundances

Ristic, M.; Holmbeck, E. M.; Wollaeger, R.; Korobkin, O.; Champion, E.; O'Shaughnessy, R.; Fryer, C. L.; Fontes, C. J.; Mumpower, M. R.; Sprouse, T. M.

doi:10.48550/arxiv.2206.02273

Cited by 3 publications

(3 citation statements)

References 53 publications

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“…They also showed that both optical and nearinfrared emissions are simultaneously reproduced by the ejecta with a medium Y e of 0.25. The recent Bayesian analysis by Ristic et al (2022) constrained a mass ratio of M w /M = 2.81 (the ratio of wind mass to dynamical ejecta mass) to reproduce the observed AT2017gfo kilonova light curves, while also being consistent with the observed r-process element abundance measured in the solar system.…”

Section: Comparison With Previous Studiessupporting

confidence: 55%

Studying Postmerger Outflows from Magnetized-neutrino-cooled Accretion Disks

Nouri

Janiuk

Przerwa

2023

ApJ

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Neutrino-cooled accretion flow around a spinning black hole, produced by a compact binary merger, is a promising scenario for jet formation and launching magnetically driven outflows. Based on GW170817 gravitational wave detection by LIGO and Virgo observatories, followed by electromagnetic counterparts, this model can explain the central engine of the short-duration gamma-ray bursts and kilonova radiations. Using the open-source general relativistic magnetohydrodynamic HARM-COOL code, we evolved several 2D magnetized accretion disk–black hole models with a realistic equation of state in the fixed curved spacetime background. We applied the particle tracer technique to measure the properties of the outflows. The disk and black hole's initial parameters are chosen in a way to represent different possible postmerger scenarios of the merging compact objects. Our simulations show a strong correlation between the black hole's spin and ejected mass. Generally, mergers producing massive disks and rapidly spinning black holes launch stronger outflows. We observed our models generate winds with moderate velocity (v/c ∼ 0.1–0.2) and a broad range of electron fractions. We use these results to estimate the luminosity and light curves of possible radioactively powered transients emitted by such systems. We found that the luminosity peaks within the range of 1040–1042 erg s−1, which agrees with previous studies for disk wind outflows.

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Section: Comparison With Previous Studiessupporting

confidence: 55%

Studying Postmerger Outflows from Magnetized-neutrino-cooled Accretion Disks

Nouri

Janiuk

Przerwa

2023

ApJ

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“…Therefore, we generated a network with ∼800 species (in the following referred to as "full network"), including all relevant nuclei up to Ge and reactions, butnot including weak reactions. 9 This generated network is compared to the well-established reaction network WINNET (Winteler et al 2012), which was already used in previous publications (e.g., Korobkin et al 2012;Winteler et al 2012;Martin et al 2015;Eichler et al 2019;Bliss et al 2020;Reichert et al 2021;Ristic et al 2022). For this, we use three different typical explosive trajectories taken from the 2D_flsh model (see Table 3).…”

Section: Discussionmentioning

confidence: 99%

Core-collapse Supernova Simulations with Reduced Nucleosynthesis Networks

Navó

Reichert

Obergaulinger

et al. 2023

ApJ

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We present core-collapse supernova simulations including nuclear reaction networks that impact explosion dynamics and nucleosynthesis. The different composition treatment can lead to changes in the neutrino heating in the vicinity of the shock by modifying the number of nucleons and thus the neutrino-opacity of the region. This reduces the ram pressure outside the shock and allows an easier expansion. The energy released by the nuclear reactions during collapse also slows down the accretion and aids the shock expansion. In addition, nuclear energy generation in the postshocked matter produces up to 20% more energetic explosions. Nucleosynthesis is affected due to the different dynamic evolution of the explosion. Our results indicate that the energy generation from nuclear reactions helps to sustain late outflows from the vicinity of the proto-neutron star, synthesizing more neutron-rich species. Furthermore, we show that there are systematic discrepancies between the ejecta calculated with in situ and ex situ reaction networks. These differences stem from the intrinsic characteristics of evolving the composition in hydrodynamic simulations or calculating it with Lagrangian tracer particles. The mass fractions of some Ca, Ti, Cr, and Fe isotopes are consistently underproduced in postprocessing calculations, leading to different nucleosynthesis paths. Our results suggest that large in situ nuclear reaction networks are important for a realistic feedback of the energy generation, the neutrino heating, and a more accurate ejecta composition.

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“…7 Previous work found that solar-like abundances can be obtained by combining individual trajectories with both high initial Y e as well as low initial Y e (Zhu et al 2021). Our goal is not necessarily to obtain a solar-like final abundance pattern (we direct the reader to, for example, Ristic et al 2022, which addresses r-process universality), since we do not know if KN events produce a solar pattern. Rather we aim to sample a variety of trajectories containing material with a variety of neutron richness, whether from dynamical ejecta plus disk outflows or from multicomponent disk outflows.…”

Section: Model Set and Nucleosynthesismentioning

confidence: 99%

The Influence of β-decay Rates on r-process Observables

Lund

Engel

McLaughlin

et al. 2023

ApJ

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The rapid neutron capture process (r-process) is one of the main mechanisms whereby elements heavier than iron are synthesized, and is entirely responsible for the natural production of the actinides. Kilonova emissions are modeled as being largely powered by the radioactive decay of species synthesized via the r-process. Given that the r-process occurs far from nuclear stability, unmeasured beta-decay rates play an essential role in setting the timescale for the r-process. In an effort to better understand the sensitivity of kilonova modeling to different theoretical global beta-decay descriptions, we incorporate these into nucleosynthesis calculations. We compare the results of these calculations and highlight differences in kilonova nuclear energy generation and light-curve predictions, as well as final abundances and their implications for nuclear cosmochronometry. We investigate scenarios where differences in beta-decay rates are responsible for increased nuclear heating on timescales of days that propagates into a significantly increased average bolometric luminosity between 1 and 10 days post-merger. We identify key nuclei, both measured and unmeasured, whose decay rates directly impact nuclear heating generation on timescales responsible for light-curve evolution. We also find that uncertainties in beta-decay rates significantly impact age estimates from cosmochronometry.

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Constraining inputs to realistic kilonova simulations through comparison to observed r-process abundances

Cited by 3 publications

References 53 publications

Studying Postmerger Outflows from Magnetized-neutrino-cooled Accretion Disks

Studying Postmerger Outflows from Magnetized-neutrino-cooled Accretion Disks

Core-collapse Supernova Simulations with Reduced Nucleosynthesis Networks

The Influence of β-decay Rates on r-process Observables

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