Long gamma-ray burst as a production site of r-process elements

2012 ◽  
Author(s):  
Ko Nakamrua ◽  
Seiji Harikae ◽  
Toshitaka Kajino ◽  
Grant J. Mathews
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Burst ◽  
Production Site ◽  
R Process ◽  
Process Elements

scholarly journals A luminosity distribution for kilonovae based on short gamma-ray burst afterglows

2019 ◽  
Vol 486 (1) ◽  
pp. 672-690 ◽  
Author(s):  
Stefano Ascenzi ◽  
Michael W Coughlin ◽  
Tim Dietrich ◽  
Ryan J Foley ◽  
Enrico Ramirez-Ruiz ◽  
...  
Keyword(s):  
Near Infrared ◽  
Gamma Ray ◽  
Radioactive Decay ◽  
Infrared Emission ◽  
Gamma Ray Burst ◽  
Peak Magnitude ◽  
Upper Limits ◽  
R Process ◽  
Process Elements ◽  
First Time

Abstract The combined detection of a gravitational-wave signal, kilonova, and short gamma-ray burst (sGRB) from GW170817 marked a scientific breakthrough in the field of multimessenger astronomy. But even before GW170817, there have been a number of sGRBs with possible associated kilonova detections. In this work, we re-examine these ‘historical’ sGRB afterglows with a combination of state-of-the-art afterglow and kilonova models. This allows us to include optical/near-infrared synchrotron emission produced by the sGRB as well as ultraviolet/optical/near-infrared emission powered by the radioactive decay of r-process elements (i.e. the kilonova). Fitting the light curves, we derive the velocity and the mass distribution as well as the composition of the ejected material. The posteriors on kilonova parameters obtained from the fit were turned into distributions for the peak magnitude of the kilonova emission in different bands and the time at which this peak occurs. From the sGRB with an associated kilonova, we found that the peak magnitude in H bands falls in the range [−16.2, −13.1] ($95{{\ \rm per\ cent}}$ of confidence) and occurs within $0.8\!-\!3.6\, \rm d$ after the sGRB prompt emission. In g band instead we obtain a peak magnitude in range [−16.8, −12.3] occurring within the first 18 h after the sGRB prompt. From the luminosity distributions of GW170817/AT2017gfo, kilonova candidates GRB130603B, GRB050709, and GRB060614 (with the possible inclusion of GRB150101B, GRB050724A, GRB061201, GRB080905A, GRB150424A, and GRB160821B) and the upper limits from all the other sGRBs not associated with any kilonova detection we obtain for the first time a kilonova luminosity distribution in different bands.

scholarly journals Prospects for obtaining an r process from Gamma Ray Burst Disk Winds

2005 ◽  
Vol 758 ◽  
pp. 189-196 ◽  
Author(s):  
G.C. McLaughlin ◽  
R. Surman
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Burst ◽  
R Process

scholarly journals Neutron star mergers as sites of r-process nucleosynthesis and short gamma-ray bursts

2018 ◽  
Vol 27 (13) ◽  
pp. 1842005 ◽  
Author(s):  
Kenta Hotokezaka ◽  
Paz Beniamini ◽  
Tsvi Piran
Keyword(s):  
Neutron Star ◽  
Chemical Evolution ◽  
Near Infrared ◽  
Gamma Ray ◽  
Ultra Violet ◽  
Gamma Ray Bursts ◽  
Galactic Model ◽  
Multi Wavelength ◽  
R Process ◽  
Process Elements

Neutron star mergers have been long considered as promising sites of heavy [Formula: see text]-process nucleosynthesis. We overview the observational evidence supporting this scenario including: the total amount of [Formula: see text]-process elements in the galaxy, extreme metal-poor stars, geological radioactive elemental abundances, dwarf galaxies and short gamma-ray bursts (sGRBs). Recently, the advanced LIGO and Virgo observatories discovered a gravitational-wave signal of a neutron star merger, GW170817, as well as accompanying multi-wavelength electromagnetic (EM) counterparts. The ultra-violet, optical and near infrared (n/R) observations point to [Formula: see text]-process elements that have been synthesized in the merger ejecta. The rate and ejected mass inferred from GW170817 and the EM counterparts are consistent with other observations. We however, find that, within the simple one zone chemical evolution models (based on merger rates with reasonable delay time distributions as expected from evolutionary models, or from observations of sGRBs), it is difficult to reconcile the current observations of the Eu abundance history of galactic stars for [Fe/H] [Formula: see text]. This implies that to account for the role of mergers in the galactic chemical evolution, we need a galactic model with multiple populations that have different spatial distributions and/or varying formation rates.

scholarly journals Gamma-Ray Emission Produced by r-process Elements from Neutron Star Mergers

2021 ◽  
Vol 919 (1) ◽  
pp. 59
Author(s):  
Meng-Hua Chen ◽  
Li-Xin Li ◽  
Da-Bin Lin ◽  
En-Wei Liang
Keyword(s):  
Neutron Star ◽  
Gamma Ray ◽  
Gamma Ray Emission ◽  
R Process ◽  
Process Elements

scholarly journals A line-binned treatment of opacities for the spectra and light curves from neutron star mergers

2020 ◽  
Vol 493 (3) ◽  
pp. 4143-4171 ◽  
Author(s):  
C J Fontes ◽  
C L Fryer ◽  
A L Hungerford ◽  
R T Wollaeger ◽  
O Korobkin
Keyword(s):  
Neutron Star ◽  
Gamma Ray ◽  
Radiation Transport ◽  
Electromagnetic Transients ◽  
Actinide Element ◽  
Structure Line ◽  
Spectral Simulations ◽  
R Process ◽  
Process Elements ◽  
Area Preserving

ABSTRACT The electromagnetic observations of GW170817 were able to dramatically increase our understanding of neutron star mergers beyond what we learned from gravitational waves alone. These observations provided insight on all aspects of the merger from the nature of the gamma-ray burst to the characteristics of the ejected material. The ejecta of neutron star mergers are expected to produce such electromagnetic transients, called kilonovae or macronovae. Characteristics of the ejecta include large velocity gradients, relative to supernovae, and the presence of heavy r-process elements, which pose significant challenges to the accurate calculation of radiative opacities and radiation transport. For example, these opacities include a dense forest of bound–bound features arising from near-neutral lanthanide and actinide elements. Here we investigate the use of fine-structure, line-binned opacities that preserve the integral of the opacity over frequency. Advantages of this area-preserving approach over the traditional expansion–opacity formalism include the ability to pre-calculate opacity tables that are independent of the type of hydrodynamic expansion and thus eliminate the computational expense of calculating opacities within radiation-transport simulations. Tabular opacities are generated for all 14 lanthanides as well as a representative actinide element, uranium. We demonstrate that spectral simulations produced with the line-binned opacities agree well with results produced with the more accurate continuous Monte Carlo Sobolev approach, as well as with the commonly used expansion–opacity formalism. The agreement between the line-binned and expansion–opacity results is explained as arising from the similarity in their opacities in the limit of low optical depth, where radiation transport is important in the ejecta. Additional investigations illustrate the convergence of opacity with respect to the number of included lines, and elucidate sensitivities to different atomic physics approximations, such as fully and semirelativistic approaches.

scholarly journals Predicted rates of merging neutron stars in galaxies

2020 ◽  
Vol 500 (1) ◽  
pp. 1071-1086
Author(s):  
Marta Molero ◽  
Paolo Simonetti ◽  
Francesca Matteucci ◽  
Massimo della Valle
Keyword(s):  
Distribution Function ◽  
Time Delay ◽  
Neutron Stars ◽  
Gamma Ray ◽  
High Redshift ◽  
Core Collapse ◽  
R Process ◽  
Process Elements ◽  
Luminosity Evolution ◽  
The Eu

ABSTRACT We compute rates of merging neutron stars (MNS) in different galaxies, as well as the cosmic MNS rate in different cosmological scenarios. Our aim is to provide predictions of kilonova rates for future observations both at low and high redshift. In the adopted galaxy models, the production of r-process elements either by MNS or core-collapse supernovae is taken into account. To compute the MNS rates, we adopt either a constant total time delay for merging (10 Myr) or a distribution function of such delays. We conclude (i) the observed present time MNS rate in our Galaxy is well reproduced either with a constant time delay or a distribution function ∝t−1. (ii) The [Eu/Fe] versus [Fe/H] relation can be well reproduced with only MNS, if the time delay is short and constant. If a distribution function of delays is adopted, core-collapse supernovae are also required. (iii) The present time cosmic MNS rate can be well reproduced in several cosmological scenarios. (iv) Spiral galaxies are the major contributors to the cosmic MNS at all redshifts in hierarchical scenarios. In the pure luminosity evolution scenario, the spirals are the major contributors locally, whereas at high redshift ellipticals dominate. (v) The predicted cosmic MNS rate well agrees with the cosmic rate of short gamma-ray bursts, if the distribution function of delays is adopted in a cosmological hierarchical scenario observationally derived. (vi) Future observations of kilonovae in ellipticals will allow us to disentangle among constant or a distribution of time delays and among different cosmological scenarios.

Distribution of R- and S-Process Elements in the Galactic Halo

1988 ◽  
Vol 132 ◽  
pp. 501-506
Author(s):  
C. Sneden ◽  
C. A. Pilachowski ◽  
K. K. Gilroy ◽  
J. J. Cowan
Keyword(s):  
Heavy Element ◽  
Galactic Halo ◽  
Low Noise ◽  
Heavy Elements ◽  
Process Synthesis ◽  
Element Abundances ◽  
Halo Stars ◽  
Abundance Patterns ◽  
R Process ◽  
Process Elements

Current observational results for the abundances of the very heavy elements (Z>30) in Population II halo stars are reviewed. New high resolution, low noise spectra of many of these extremely metal-poor stars reveal general consistency in their overall abundance patterns. Below Galactic metallicities of [Fe/H] Ã −2, all of the very heavy elements were manufactured almost exclusively in r-process synthesis events. However, there is considerable star-to-star scatter in the overall level of very heavy element abundances, indicating the influence of local supernovas on element production in the very early, unmixed Galactic halo. The s-process appears to contribute substantially to stellar abundances only in stars more metal-rich than [Fe/H] Ã −2.

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