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Related papers: Non-Thermal Ionization of Kilonova Ejecta: Observa…

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Kilonovae are generally believed to originate from the ejecta of binary neutron stars (NSs) or black hole and NS mergers. Free neutrons might be retained in the outermost layer of the ejecta to produce a precursor via $\beta$-decay. During…

High Energy Astrophysical Phenomena · Physics 2023-03-08 Yan-Qing Qi , Tong Liu

We present an improved version of the 3D Monte Carlo radiative transfer code POSSIS to model kilonovae from neutron star mergers, wherein nuclear heating rates, thermalization efficiencies and wavelength-dependent opacities depend on local…

High Energy Astrophysical Phenomena · Physics 2023-02-01 Mattia Bulla

We constructed a comprehensive model atom for C\ione\ -- C\ii\ using the most up-to-date atomic data available and evaluated the non-local thermodynamic equilibrium (NLTE) line formation for C\ione\ and C\ii\ in classical 1D models…

Solar and Stellar Astrophysics · Physics 2016-08-17 S. A. Alexeeva , T. A. Ryabchikova , L. I. Mashonkina

We ensure successful explosions (of otherwise non-explosive models) by enhancing the neutrino luminosity via reducing the neutrino scattering cross sections or by increasing the heating efficiency via enhancing the neutrino absorption cross…

Realistic atmospheric models that link the properties and the physical conditions of supernova ejecta to observable spectra are required for the quantitative interpretation of observational data of type Ia supernovae (SN Ia) and the…

Astrophysics · Physics 2007-05-23 D. N. Sauer , T. L. Hoffmann , A. W. A. Pauldrach

The kilonova associated with GW170817 displayed early blue emission which has been interpreted as a signature of either radioactive decay in low-opacity ejecta, relativistic boosting of radioactive decay in high-velocity ejecta, the cooling…

High Energy Astrophysical Phenomena · Physics 2018-03-28 Iair Arcavi

A central question regarding neutron star mergers is whether they are able to produce all the r-process elements, from first to third peak. The high abundances of first-peak elements (atomic number $Z \sim 31-40$) in the solar composition…

A binary neutron star merger is expected to be associated by a kilonova, transient optical emission powered by radioactive decay of the neutron-rich ejecta. If the post-merger remnant is a long-lived neutron star, additional energy…

High Energy Astrophysical Phenomena · Physics 2022-09-21 Shunke Ai , Bing Zhang , Zhaohuan Zhu

The merger of two neutron stars (NSs) or a neutron star and a black hole (BH) produces a radioactively-powered transient known as a kilonova, first observed accompanying the gravitational wave event GW170817. While kilonovae are frequently…

High Energy Astrophysical Phenomena · Physics 2021-03-17 Siva Darbha , Daniel Kasen

Many promising explosion models for the elusive origin of Type Ia supernovae (SNe Ia) ultimately fail to completely reproduce a number of observed properties of these events. One limiting factor for many of these models is the use of the…

High Energy Astrophysical Phenomena · Physics 2025-05-19 Samuel J. Boos , Luc Dessart , Ken J. Shen , Dean M. Townsley

We consider a simple model for the nonthermal emission from GW170817, in which a quasi-spherical ejecta is released in the merger event, with the kinetic energy distributed over the momentum as $E(>\gamma\beta)\propto(\gamma\beta)^{-k}$.…

High Energy Astrophysical Phenomena · Physics 2018-08-08 Yan Huang , Zhuo Li

The detailed observations of GW170817 proved for the first time directly that neutron star mergers are a major production site of heavy elements. The observations could be fit by a number of simulations that qualitatively agree, but can…

Detecting the thermal emission from double neutron star merger events is a challenging task because of the quick fading of the observed flux. In order to create an efficient observing strategy for their observing method it is crucial to…

High Energy Astrophysical Phenomena · Physics 2020-10-19 József Kóbori , Zsolt Bagoly , Lajos G. Balázs

Manganese (Mn) is a key Fe-group elements, commonly employed in stellar population and nucleosynthesis studies to explore the role of SN Ia. We have developed a new non-local thermodynamic equilibrium (NLTE) model of Mn, including new…

The observed spectra and light curves of the kilonova produced by the GW170817 binary neutron star merger provide complementary insights, but modeling both the spectral- and time-domain has proven challenging. Here, we model the…

High Energy Astrophysical Phenomena · Physics 2025-11-14 Nicholas Vieira , John J. Ruan , Daryl Haggard , Maria R. Drout , Rodrigo Fernández

Dust is expected to form on a year timescale in core-collapse supernova (SN) ejecta. Its existence is revealed through an infrared brightening, an optical dimming, or a blue-red emission-line profile asymmetry. To investigate how the dust…

Solar and Stellar Astrophysics · Physics 2025-06-25 Luc Dessart , D. John Hillier , Arkaprabha Sarangi

Non-local thermodynamic equilibrium (NLTE) effects in diagnostically important solar Fe I lines are important due to the strong sensitivity of Fe I to ionizing UV radiation, which may lead to a considerable under-population of the Fe I…

Solar and Stellar Astrophysics · Physics 2015-10-21 René Holzreuter , Sami K. Solanki

We investigate the kilonova emission resulting from outflows produced in a three-dimensional (3D) general-relativistic magnetohydrodynamic (GRMHD) simulation of a hypermassive neutron star (HMNS) remnant. We map the outflows into the FLASH…

High Energy Astrophysical Phenomena · Physics 2025-11-18 Lieke Sippens Groenewegen , Sanjana Curtis , Philipp Mösta , Daniel Kasen , Daniel Brethauer

Most of the physical information about astrophysical objects is obtained via the analysis of their electromagnetic spectra. Observed data coupled with radiation transfer models in physical conditions representative of stars, planets,…

Solar and Stellar Astrophysics · Physics 2026-05-29 Maria Bergemann , Richard Hoppe

The current analysis is dedicated to a detailed investigation of the non-Local Thermodynamic Equilibrium (NLTE) effects influencing the formation of the Fe I 6173 A line, which is widely used by many instruments including the Helioseismic…

Solar and Stellar Astrophysics · Physics 2023-01-25 H. N. Smitha , M. van Noort , S. K. Solanki , J. S. Castellanos Durán