scholarly journals r-Process Nucleosynthesis in Black Hole - Neutron Star Mergers

2009 ◽  
Author(s):  
Rebecca Surman ◽  
Gail C. Mclaughlin ◽  
M. Ruffert ◽  
Hans-thomas Janka ◽  
William Raphael Hix
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
R Process

scholarly journals Merger and Mass Ejection of Neutron Star Binaries

2019 ◽  
Vol 69 (1) ◽  
pp. 41-64 ◽  
Author(s):  
Masaru Shibata ◽  
Kenta Hotokezaka
Keyword(s):  
Numerical Simulation ◽  
Black Hole ◽  
Neutron Star ◽  
Numerical Relativity ◽  
High Energy ◽  
Ejection Process ◽  
Merger Process ◽  
Unique Approach ◽  
R Process ◽  
Mass Ejection

Mergers of binary neutron stars and black hole–neutron star binaries are among the most promising sources for ground-based gravitational-wave (GW) detectors and are also high-energy astrophysical phenomena, as illustrated by the observations of GWs and electromagnetic (EM) waves in the event of GW170817. Mergers of these neutron star binaries are also the most promising sites for r-process nucleosynthesis. Numerical simulation in full general relativity (numerical relativity) is a unique approach to the theoretical prediction of the merger process, GWs emitted, mass ejection process, and resulting EM emission. We summarize the current understanding of the processes of neutron star mergers and subsequent mass ejection based on the results of the latest numerical-relativity simulations. We emphasize that the predictions of the numerical-relativity simulations agree broadly with the optical and IR observations of GW170817.

scholarly journals r -Process Nucleosynthesis in Hot Accretion Disk Flows from Black Hole-Neutron Star Mergers

2008 ◽  
Vol 679 (2) ◽  
pp. L117-L120 ◽  
Author(s):  
R. Surman ◽  
G. C. McLaughlin ◽  
M. Ruffert ◽  
H.-Th. Janka ◽  
W. R. Hix
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Accretion Disk ◽  
R Process

scholarly journals Imprints of r-process heating on fall-back accretion: distinguishing black hole–neutron star from double neutron star mergers

2019 ◽  
Vol 485 (3) ◽  
pp. 4404-4412 ◽  
Author(s):  
D Desai ◽  
B D Metzger ◽  
F Foucart
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Neutron Star ◽  
Gamma Ray ◽  
Late Time ◽  
X Ray ◽  
Power Law Decay ◽  
Process Heating ◽  
R Process ◽  
The Impact

ABSTRACT Mergers of compact binaries containing two neutron stars (NS–NS), or a neutron star and a stellar mass black hole (NS–BH), are likely progenitors of short-duration gamma-ray bursts (SGRBs). A fraction ${\gtrsim } 20{{\ \rm per\ cent}}$ of SGRBs is followed by temporally extended (≳minute-long), variable X-ray emission, attributed to ongoing activity of the central engine. One source of late-time engine activity is fall-back accretion of bound tidal ejecta; however, observed extended emission light curves do not track the naively anticipated, uninterrupted t−5/3 power-law decay, instead showing a lull or gap in emission typically lasting tens of seconds after the burst. Here, we re-examine the impact of heating due to rapid neutron capture (r-process) nucleosynthesis on the rate of the fall-back accretion, using ejecta properties extracted from numerical relativity simulations of NS–BH mergers. Heating by the r-process has its greatest impact on marginally bound matter, hence its relevance to late-time fall-back. Depending on the electron fraction of the ejecta and the mass of the remnant black hole, r-process heating can imprint a range of fall-back behaviour, ranging from temporal gaps of up to tens of seconds to complete late-time cut-off in the accretion rate. This behaviour is robust to realistic variations in the nuclear heating experienced by different parts of the ejecta. Central black holes with masses ${\lesssim } 3\, \mathrm{M}_{\odot }$ typically experience absolute cut-offs in the fall-back rate, while more massive ${\gtrsim } 6\!-\!8\, \mathrm{M}_{\odot }$ black holes instead show temporal gaps. We thus propose that SGRBs showing extended X-ray emission arise from NS–BH, rather than NS–NS, mergers. Our model implies an NS–BH merger detection rate by LIGO that, in steady state, is comparable to or greater than that of NS–NS mergers.

scholarly journals The r-process in black hole-neutron star mergers based on a fully general-relativistic simulation

2016 ◽  
Vol 665 ◽  
pp. 012059 ◽  
Author(s):  
N Nishimura ◽  
S Wanajo ◽  
Y Sekiguchi ◽  
K Kiuchi ◽  
K Kyutoku ◽  
...  
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
General Relativistic ◽  
R Process

scholarly journals Using failed supernovae to constrain the Galactic r-process element production

2019 ◽  
Vol 487 (2) ◽  
pp. 1745-1753 ◽  
Author(s):  
B Wehmeyer ◽  
C Fröhlich ◽  
B Côté ◽  
M Pignatari ◽  
F-K Thielemann
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Large Fraction ◽  
Capture Process ◽  
Compact Binary ◽  
Halo Stars ◽  
The Galaxy ◽  
Binary Mergers ◽  
R Process ◽  
Process Elements

ABSTRACT Rapid neutron capture process (r-process) elements have been detected in a large fraction of metal-poor halo stars, with abundances relative to iron (Fe) that vary by over two orders of magnitude. This scatter is reduced to less than a factor of 3 in younger Galactic disc stars. The large scatter of r-process elements in the early Galaxy suggests that the r-process is made by rare events, like compact binary mergers and rare sub-classes of supernovae. Although being rare, neutron star mergers alone have difficulties to explain the observed enhancement of r-process elements in the lowest metallicity stars compared to Fe. The supernovae producing the two neutron stars already provide a substantial Fe abundance where the r-process ejecta from the merger would be injected. In this work we investigate another complementary scenario, where the r-process occurs in neutron star-black hole mergers in addition to neutron star mergers. Neutron star-black hole mergers would eject similar amounts of r-process matter as neutron star mergers, but only the neutron star progenitor would have produced Fe. Furthermore, a reduced efficiency of Fe production from single stars significantly alters the age–metallicity relation, which shifts the onset of r-process production to lower metallicities. We use the high-resolution [(20 pc)3/cell] inhomogeneous chemical evolution tool ‘ICE’ to study the outcomes of these effects. In our simulations, an adequate combination of neutron star mergers and neutron star-black hole mergers qualitatively reproduces the observed r-process abundances in the Galaxy.

scholarly journals The influence of neutrinos on r-process nucleosynthesis in the ejecta of black hole–neutron star mergers

2016 ◽  
Vol 464 (4) ◽  
pp. 3907-3919 ◽  
Author(s):  
Luke F. Roberts ◽  
Jonas Lippuner ◽  
Matthew D. Duez ◽  
Joshua A. Faber ◽  
Francois Foucart ◽  
...  
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
R Process

scholarly journals Fission fragment distributions and their impact on the r -process nucleosynthesis in neutron star mergers

2021 ◽  
Vol 103 (2) ◽  
Author(s):  
J.-F. Lemaître ◽  
S. Goriely ◽  
A. Bauswein ◽  
H.-T. Janka
Keyword(s):  
Neutron Star ◽  
Fission Fragment ◽  
R Process

scholarly journals A minimal timescale for the continuum in 4U 1608-52 and Aql X-1

2021 ◽  
Vol 502 (1) ◽  
pp. L72-L78
Author(s):  
K Mohamed ◽  
E Sonbas ◽  
K S Dhuga ◽  
E Göğüş ◽  
A Tuncer ◽  
...  
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Power Spectra ◽  
Light Curves ◽  
State Transitions ◽  
Strong Positive Correlation ◽  
Present Evidence ◽  
X Ray ◽  
X Ray Binaries ◽  
The Continuum

ABSTRACT Similar to black hole X-ray binary transients, hysteresis-like state transitions are also seen in some neutron-star X-ray binaries. Using a method based on wavelets and light curves constructed from archival Rossi X-ray Timing Explorer observations, we extract a minimal timescale over the complete range of transitions for 4U 1608-52 during the 2002 and 2007 outbursts and the 1999 and 2000 outbursts for Aql X-1. We present evidence for a strong positive correlation between this minimal timescale and a similar timescale extracted from the corresponding power spectra of these sources.

scholarly journals High-accuracy waveforms for black hole-neutron star systems with spinning black holes

2021 ◽  
Vol 103 (6) ◽  
Author(s):  
Francois Foucart ◽  
Alexander Chernoglazov ◽  
Michael Boyle ◽  
Tanja Hinderer ◽  
Max Miller ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Neutron Star ◽  
High Accuracy
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