Author: Vimal VijayanPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
Systematic Study of Binary Neutron Star Mergers with Neutrinos and Pions
Universal Relations for Binary Neutron Star Mergers with Long-lived Remnants
Author: Praveen ManoharanPublisher: Springer Nature
ISBN: 3658368411
Category : Science
Languages : en
Pages : 77
Book Description
In the last 25 years, an extensive body of work has developed various equation of state independent - or (approximately) universal - relations that allow for the inference of neutron star parameters from gravitational wave observations. These works, however, have mostly been focused on singular neutron stars, while our observational efforts at the present, and in the near future, will be focused on binary neutron star (BNS) mergers. In light of these circumstances, the last five years have also given rise to more attempts at developing universal relations that relate BNS pre-merger neutron stars to stellar parameters of the post-merger object, mostly driven by numerical relativity simulations. In this thesis a first attempt at perturbatively deriving universal relations for binary neutron star mergers with long-lived neutron star remnants is presented. The author succeeds in confirming previous results relating pre-merger binary tidal deformabilities to the f-mode frequency of the post-merger object. Combining this result with recent advances of computing the f-mode frequency of fast rotating neutron stars, he also derives a combined relation that relates the pre-merger binary tidal deformability of a BNS to the effective compactness of a long-lived neutron star remnant. Finally, he also proposes a direct relation between these quantities with improved accuracy.
Search for High-energy Neutrinos from Binary Neutron Star Merger GW170817 with ANTARES, IceCube, and the Pierre Auger Observatory
Author: Binary Neutron Star Mergers and Electromagnetic Counterparts
Author: Vsevolod NedoraPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
In August 2017, a merger of two neutron stars (NSs) was detected for the first time via several carriers. Observed in gravitational waves, as well as in the electromagnetic spectrum, the GW170817 marked the dawn of multi-messenger astronomy for compact object mergers, and shed light on numerous astrophysical aspects of binary neutron star (BNS) mergers and on the properties of matter at supranuclear densities. And yet many questions remain, starting with the outcome of the merger. Was it a massive NS temporarily supported against collapse, or a black hole? How important are BNS mergers in cosmic chemical evolution, i.e., the evolution of spatial and temporal distributions of heavy elements in galaxies? It is known that they enrich their surroundings with very heavy elements, but are they the dominant source of these elements? Modeling these events on the computer, do we understand them correctly, i.e., do our predictions regarding the properties of the ejected matter and its EM signatures agree with the newly gained data? This thesis is dedicated to addressing these questions by means of analyzing a large set of numerical simulations of BNS mergers, performed with state-of-the-art numerical tools, and targeted specifically to GW170817. Employing a suite of postprocessing tools we study the matter dynamics. Special attention is given to matter, ejected from the system during and after merger, so-called ejecta. With the help of a parameterized nucleosynthesis model, we study the final abundances of heavy elements in ejecta, comparing them to solar abundances. Furthermore, we investigate EM emission, powered by the decay of newly synthesized heavy elements, comparing it to the observations of GW170817. Finally, we study the long-term emission of the ejected material as it propagates through the interstellar medium (ISM), via our new numerical tools, comparing the results with a recently detected change in the emission from GW170817.
Numerical Evolution of Binary Neutron Star Mergers
Author: Peter Christopher HammondPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
Pions in Nuclear Matter
Author: Bengt Leopold FrimanPublisher:
ISBN:
Category : Mesons
Languages : en
Pages : 368
Book Description
Neutrino, Nucleosynthesis in Neutron Star Mergers and Multi-messenger Observation
Author: Yonglin ZhuNuclear Astrophysics in Our Time: Supernovae, Neutron Stars and Binary Neutron Star Mergers
Author: Debades BandyopadhyayThe Fate of the Compact Remnant in Neutron Star Mergers
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Neutron star (binary neutron star and neutron star - black hole) mergers are believed to produce short-duration gamma-ray bursts. They are also believed to be the dominant source of gravitational waves to be detected by the advanced LIGO and the dominant source of the heavy r-process elements in the universe. Whether or not these mergers produce short-duration GRBs depends sensitively on the fate of the core of the remnant (whether, and how quickly, it forms a black hole). In this paper, we combine the results of merger calculations and equation of state studies to determine the fate of the cores of neutron star mergers. Using population studies, we can determine the distribution of these fates to compare to observations. We find that black hole cores form quickly only for equations of state that predict maximum non-rotating neutron star masses below 2.3-2.4 solar masses. If quick black hole formation is essential in producing gamma-ray bursts, LIGO observed rates compared to GRB rates could be used to constrain the equation of state for dense nuclear matter.
The Threshold to Prompt Collapse of Binary Neutron Star Mergers
Author: Maximilian KölschPublisher:
ISBN:
Category :
Languages : de
Pages : 0
Book Description
The next observing runs of advanced gravitational-wave detectors will lead to a variety of binary neutron star detections and numerous possibilities for multi-messenger observations of binary neutron star systems. In this context a clear understanding of the merger process and the possibility of prompt black hole formation after merger is important, as the amount of ejected material strongly depends on the merger dynamics. These dynamics are primarily affected by the total mass of the binary, however, the mass ratio also influences the postmerger evolution. To determine the effect of the mass ratio, we investigate the parameter space around the prompt-collapse threshold with a new set of more than 300 fully relativistic simulations, considering 165 different binary configurations. The simulations cover three equations of state and seven mass ratios in the range of 1.0≤q≤1.75, with five to seven simulations of binary systems of different total mass in each case. The threshold mass is determined through an empirical relation based on the collapse-time, which allows us to investigate effects of the mass-ratio on the threshold mass and also on the properties of the remnant system. Furthermore, we model effects of mass ratio and equation of state on tidal parameters of threshold configurations.